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Myocardial Infarction

Myocardial infarction is ischemia Ischemia A hypoperfusion of the blood through an organ or tissue caused by a pathologic constriction or obstruction of its blood vessels, or an absence of blood circulation. Ischemic Cell Damage and death of an area of myocardial tissue due to insufficient blood flow Flow Blood flows through the heart, arteries, capillaries, and veins in a closed, continuous circuit. Flow is the movement of volume per unit of time. Flow is affected by the pressure gradient and the resistance fluid encounters between 2 points. Vascular resistance is the opposition to flow, which is caused primarily by blood friction against vessel walls. Vascular Resistance, Flow, and Mean Arterial Pressure and oxygenation, usually from thrombus formation on a ruptured atherosclerotic plaque Atherosclerotic plaque Lesions formed within the walls of arteries. Atherosclerosis in the epicardial arteries Arteries Arteries are tubular collections of cells that transport oxygenated blood and nutrients from the heart to the tissues of the body. The blood passes through the arteries in order of decreasing luminal diameter, starting in the largest artery (the aorta) and ending in the small arterioles. Arteries are classified into 3 types: large elastic arteries, medium muscular arteries, and small arteries and arterioles. Arteries: Histology. Clinical presentation Presentation The position or orientation of the fetus at near term or during obstetric labor, determined by its relation to the spine of the mother and the birth canal. The normal position is a vertical, cephalic presentation with the fetal vertex flexed on the neck. Normal and Abnormal Labor is most commonly with chest pain Chest Pain Chest pain is one of the most common and challenging complaints that may present in an inpatient and outpatient setting. The differential diagnosis of chest pain is large and includes cardiac, gastrointestinal, pulmonary, musculoskeletal, and psychiatric etiologies. Chest Pain, but women and patients Patients Individuals participating in the health care system for the purpose of receiving therapeutic, diagnostic, or preventive procedures. Clinician–Patient Relationship with diabetes Diabetes Diabetes mellitus (DM) is a metabolic disease characterized by hyperglycemia and dysfunction of the regulation of glucose metabolism by insulin. Type 1 DM is diagnosed mostly in children and young adults as the result of autoimmune destruction of β cells in the pancreas and the resulting lack of insulin. Type 2 DM has a significant association with obesity and is characterized by insulin resistance. Diabetes Mellitus may have atypical symptoms. Diagnosis is by clinical history, ECG ECG An electrocardiogram (ECG) is a graphic representation of the electrical activity of the heart plotted against time. Adhesive electrodes are affixed to the skin surface allowing measurement of cardiac impulses from many angles. The ECG provides 3-dimensional information about the conduction system of the heart, the myocardium, and other cardiac structures. Electrocardiogram (ECG) changes, an increase in cardiac Cardiac Total Anomalous Pulmonary Venous Return (TAPVR) enzymes Enzymes Enzymes are complex protein biocatalysts that accelerate chemical reactions without being consumed by them. Due to the body's constant metabolic needs, the absence of enzymes would make life unsustainable, as reactions would occur too slowly without these molecules. Basics of Enzymes, and evidence of wall motion abnormalities on imaging. Management depends on the timing of the presentation Presentation The position or orientation of the fetus at near term or during obstetric labor, determined by its relation to the spine of the mother and the birth canal. The normal position is a vertical, cephalic presentation with the fetal vertex flexed on the neck. Normal and Abnormal Labor and local resources with regard to thrombolytic therapy versus percutaneous intervention. All patients Patients Individuals participating in the health care system for the purpose of receiving therapeutic, diagnostic, or preventive procedures. Clinician–Patient Relationship receive nitrates Nitrates Nitrates are a class of medications that cause systemic vasodilation (veins > arteries) by smooth muscle relaxation. Nitrates are primarily indicated for the treatment of angina, where preferential venodilation causes pooling of blood, decreased preload, and ultimately decreased myocardial O2 demand. Nitrates, pain Pain An unpleasant sensation induced by noxious stimuli which are detected by nerve endings of nociceptive neurons. Pain: Types and Pathways control, aspirin Aspirin The prototypical analgesic used in the treatment of mild to moderate pain. It has anti-inflammatory and antipyretic properties and acts as an inhibitor of cyclooxygenase which results in the inhibition of the biosynthesis of prostaglandins. Aspirin also inhibits platelet aggregation and is used in the prevention of arterial and venous thrombosis. Nonsteroidal Antiinflammatory Drugs (NSAIDs), anticoagulation Anticoagulation Pulmonary Hypertension Drugs, and beta-blockers Beta-blockers Drugs that bind to but do not activate beta-adrenergic receptors thereby blocking the actions of beta-adrenergic agonists. Adrenergic beta-antagonists are used for treatment of hypertension, cardiac arrhythmias, angina pectoris, glaucoma, migraine headaches, and anxiety. Class 2 Antiarrhythmic Drugs (Beta Blockers) (unless contraindicated).

Last updated: 14 Mar, 2022

Editorial responsibility: Stanley Oiseth, Lindsay Jones, Evelin Maza

Overview

Definition

Myocardial infarction (MI), commonly known as a “heart attack,” is defined as acute myocardial injury and tissue death resulting from ischemia Ischemia A hypoperfusion of the blood through an organ or tissue caused by a pathologic constriction or obstruction of its blood vessels, or an absence of blood circulation. Ischemic Cell Damage.

Epidemiology

  • One of the leading causes of death in the United States
  • Prevalence Prevalence The total number of cases of a given disease in a specified population at a designated time. It is differentiated from incidence, which refers to the number of new cases in the population at a given time. Measures of Disease Frequency: 3% in Americans > 20 years of age
  • Incidence Incidence The number of new cases of a given disease during a given period in a specified population. It also is used for the rate at which new events occur in a defined population. It is differentiated from prevalence, which refers to all cases in the population at a given time. Measures of Disease Frequency in the United States:
    • 600 cases per 100,000 people
    • 1.5 million cases annually
  • More common in older patients Patients Individuals participating in the health care system for the purpose of receiving therapeutic, diagnostic, or preventive procedures. Clinician–Patient Relationship:
    • Approximately 60%–65% of MIs occur in patients Patients Individuals participating in the health care system for the purpose of receiving therapeutic, diagnostic, or preventive procedures. Clinician–Patient Relationship > 65 years of age.
    • Approximately 33% of MIs occur in patients Patients Individuals participating in the health care system for the purpose of receiving therapeutic, diagnostic, or preventive procedures. Clinician–Patient Relationship > 75 years of age.
    • 80% of all MI-related deaths occur in patients Patients Individuals participating in the health care system for the purpose of receiving therapeutic, diagnostic, or preventive procedures. Clinician–Patient Relationship > 65 years of age.
  • Men > women

Risk factors

The risks of MI increase proportionately with increases in risk factors for coronary atherosclerosis Atherosclerosis Atherosclerosis is a common form of arterial disease in which lipid deposition forms a plaque in the blood vessel walls. Atherosclerosis is an incurable disease, for which there are clearly defined risk factors that often can be reduced through a change in lifestyle and behavior of the patient. Atherosclerosis (also known as coronary artery Coronary Artery Truncus Arteriosus disease (CAD)).

  • Hypertension Hypertension Hypertension, or high blood pressure, is a common disease that manifests as elevated systemic arterial pressures. Hypertension is most often asymptomatic and is found incidentally as part of a routine physical examination or during triage for an unrelated medical encounter. Hypertension
  • Hyperlipidemia
  • Smoking Smoking Willful or deliberate act of inhaling and exhaling smoke from burning substances or agents held by hand. Interstitial Lung Diseases
  • Age: elderly individuals are more likely to:
    • Have STEMI than NSTEMI 
    • Have a silent or unrecognized MI
    • Present with atypical symptoms (e.g., weakness, confusion, syncope Syncope Syncope is a short-term loss of consciousness and loss of postural stability followed by spontaneous return of consciousness to the previous neurologic baseline without the need for resuscitation. The condition is caused by transient interruption of cerebral blood flow that may be benign or related to a underlying life-threatening condition. Syncope)
    • Have higher in-hospital mortality Mortality All deaths reported in a given population. Measures of Health Status
    • Have heart failure Heart Failure A heterogeneous condition in which the heart is unable to pump out sufficient blood to meet the metabolic need of the body. Heart failure can be caused by structural defects, functional abnormalities (ventricular dysfunction), or a sudden overload beyond its capacity. Chronic heart failure is more common than acute heart failure which results from sudden insult to cardiac function, such as myocardial infarction. Total Anomalous Pulmonary Venous Return (TAPVR) associated with an MI
  • Family history Family History Adult Health Maintenance of premature Premature Childbirth before 37 weeks of pregnancy (259 days from the first day of the mother’s last menstrual period, or 245 days after fertilization). Necrotizing Enterocolitis coronary heart disease Coronary heart disease Coronary heart disease (CHD), or ischemic heart disease, describes a situation in which an inadequate supply of blood to the myocardium exists due to a stenosis of the coronary arteries, typically from atherosclerosis. Coronary Heart Disease (CHD), defined as:
    • A 1st-degree male relative < 45 years of age
    • A 1st-degree female relative < 55 years of age

Classification

Classification of MI according to the assumed cause:

  • Type 1 Type 1 Spinal Muscular Atrophy: acute thrombus on a ruptured atherosclerotic plaque Atherosclerotic plaque Lesions formed within the walls of arteries. Atherosclerosis
  • Type 2 Type 2 Spinal Muscular Atrophy: ↑ oxygen demand in the myocardium Myocardium The muscle tissue of the heart. It is composed of striated, involuntary muscle cells connected to form the contractile pump to generate blood flow. Heart: Anatomy without adequate oxygen supply (whether or not there is underlying atherosclerotic CAD)
  • Type 3 Type 3 Spinal Muscular Atrophy: clinical symptoms of MI with ECG ECG An electrocardiogram (ECG) is a graphic representation of the electrical activity of the heart plotted against time. Adhesive electrodes are affixed to the skin surface allowing measurement of cardiac impulses from many angles. The ECG provides 3-dimensional information about the conduction system of the heart, the myocardium, and other cardiac structures. Electrocardiogram (ECG) changes, but with death of the patient occurring before lab tests are performed
  • Type 4a: MI associated with percutaneous coronary intervention Percutaneous coronary intervention A family of percutaneous techniques that are used to manage coronary occlusion, including standard balloon angioplasty (percutaneous transluminal coronary angioplasty), the placement of intracoronary stents, and atheroablative technologies (e.g., atherectomy; endarterectomy; thrombectomy; percutaneous transluminal laser angioplasty). Ptca was the dominant form of pci, before the widespread use of stenting. Cardiac Surgery ( PCI PCI Penetrating chest injuries (PCI) are caused by an object puncturing the chest wall. Penetrating chest injuries can be high velocity, such as with gunshot wounds (GSWs); medium velocity, such as with pellet gunshots; or low velocity, such as with stab wounds. Penetrating Chest Injury) or from procedure-related complications associated with ↓ coronary blood flow Flow Blood flows through the heart, arteries, capillaries, and veins in a closed, continuous circuit. Flow is the movement of volume per unit of time. Flow is affected by the pressure gradient and the resistance fluid encounters between 2 points. Vascular resistance is the opposition to flow, which is caused primarily by blood friction against vessel walls. Vascular Resistance, Flow, and Mean Arterial Pressure.
  • Type 4b: intervention-related MI with stent/scaffold thrombosis Thrombosis Formation and development of a thrombus or blood clot in the blood vessel. Epidemic Typhus
  • Type 5: MI related to coronary artery bypass graft Coronary Artery Bypass Graft Cardiac Surgery ( CABG CABG Surgical therapy of ischemic coronary artery disease achieved by grafting a section of saphenous vein, internal mammary artery, or other substitute between the aorta and the obstructed coronary artery distal to the obstructive lesion. Cardiac Surgery) surgery

Classification of MI based on ECG ECG An electrocardiogram (ECG) is a graphic representation of the electrical activity of the heart plotted against time. Adhesive electrodes are affixed to the skin surface allowing measurement of cardiac impulses from many angles. The ECG provides 3-dimensional information about the conduction system of the heart, the myocardium, and other cardiac structures. Electrocardiogram (ECG) findings and pathology:

  • STEMI: 
    • Due to a major occlusion of a coronary artery Coronary Artery Truncus Arteriosus, causing transmural infarction (through the heart muscle wall)
    • Produces ECG ECG An electrocardiogram (ECG) is a graphic representation of the electrical activity of the heart plotted against time. Adhesive electrodes are affixed to the skin surface allowing measurement of cardiac impulses from many angles. The ECG provides 3-dimensional information about the conduction system of the heart, the myocardium, and other cardiac structures. Electrocardiogram (ECG) changes with ST elevation and Q waves
  • NSTEMI:
    • Due to less severe occlusion of a coronary artery Coronary Artery Truncus Arteriosus, causing a subendocardial MI (not through the entire heart muscle wall)
    • ECG ECG An electrocardiogram (ECG) is a graphic representation of the electrical activity of the heart plotted against time. Adhesive electrodes are affixed to the skin surface allowing measurement of cardiac impulses from many angles. The ECG provides 3-dimensional information about the conduction system of the heart, the myocardium, and other cardiac structures. Electrocardiogram (ECG) does not show ST elevation

Pathophysiology

  • Characteristics of unstable versus stable plaque Plaque Primary Skin Lesions
  • Coronary artery Coronary Artery Truncus Arteriosus occlusion → ischemia Ischemia A hypoperfusion of the blood through an organ or tissue caused by a pathologic constriction or obstruction of its blood vessels, or an absence of blood circulation. Ischemic Cell Damage → death of the tissue (infarction) in the area of the heart supplied by that artery:
    • Partial occlusion of the coronary artery Coronary Artery Truncus Arteriosus → affects the inner myocardium Myocardium The muscle tissue of the heart. It is composed of striated, involuntary muscle cells connected to form the contractile pump to generate blood flow. Heart: Anatomy ( subendocardium Subendocardium Heart: Anatomy) → may cause: 
      • NSTEMI
      • Unstable angina Unstable angina Precordial pain at rest, which may precede a myocardial infarction. Stable and Unstable Angina (if the ischemia Ischemia A hypoperfusion of the blood through an organ or tissue caused by a pathologic constriction or obstruction of its blood vessels, or an absence of blood circulation. Ischemic Cell Damage does not result in cell death Cell death Injurious stimuli trigger the process of cellular adaptation, whereby cells respond to withstand the harmful changes in their environment. Overwhelmed adaptive mechanisms lead to cell injury. Mild stimuli produce reversible injury. If the stimulus is severe or persistent, injury becomes irreversible. Apoptosis is programmed cell death, a mechanism with both physiologic and pathologic effects. Cell Injury and Death)
    • Complete occlusion → transmural infarction → STEMI
Natural history of the vulnerable/unstable plaque

Natural history of the vulnerable/unstable plaque Plaque Primary Skin Lesions:
Unstable atherosclerotic plaques are thought to account for the majority of MIs. Characterization includes macrophage inflammation Inflammation Inflammation is a complex set of responses to infection and injury involving leukocytes as the principal cellular mediators in the body’s defense against pathogenic organisms. Inflammation is also seen as a response to tissue injury in the process of wound healing. The 5 cardinal signs of inflammation are pain, heat, redness, swelling, and loss of function. Inflammation, a thin fibrous Fibrous Fibrocystic Change cap, remodeling, microcalcification, and angiogenesis Angiogenesis Bartonella.

Image: “Natural history of the vulnerable plaque Plaque Primary Skin Lesions” by Ben Smith. License: CC BY 4.0

Clinical Presentation

The classic symptom of MI in most patients Patients Individuals participating in the health care system for the purpose of receiving therapeutic, diagnostic, or preventive procedures. Clinician–Patient Relationship is acute chest pain Chest Pain Chest pain is one of the most common and challenging complaints that may present in an inpatient and outpatient setting. The differential diagnosis of chest pain is large and includes cardiac, gastrointestinal, pulmonary, musculoskeletal, and psychiatric etiologies. Chest Pain. However, some patients Patients Individuals participating in the health care system for the purpose of receiving therapeutic, diagnostic, or preventive procedures. Clinician–Patient Relationship may present with more vague symptoms.

Symptoms

  • Typical: 
    • Chest pain Chest Pain Chest pain is one of the most common and challenging complaints that may present in an inpatient and outpatient setting. The differential diagnosis of chest pain is large and includes cardiac, gastrointestinal, pulmonary, musculoskeletal, and psychiatric etiologies. Chest Pain
      • Retrosternal
      • Dull, squeezing/pressure-like pain Pain An unpleasant sensation induced by noxious stimuli which are detected by nerve endings of nociceptive neurons. Pain: Types and Pathways
      • May radiate to the left arm Arm The arm, or “upper arm” in common usage, is the region of the upper limb that extends from the shoulder to the elbow joint and connects inferiorly to the forearm through the cubital fossa. It is divided into 2 fascial compartments (anterior and posterior). Arm: Anatomy, shoulder, or jaw Jaw The jaw is made up of the mandible, which comprises the lower jaw, and the maxilla, which comprises the upper jaw. The mandible articulates with the temporal bone via the temporomandibular joint (TMJ). The 4 muscles of mastication produce the movements of the TMJ to ensure the efficient chewing of food. Jaw and Temporomandibular Joint: Anatomy
      • Usually constant, lasting ≥ 20–30 minutes 
    • Diaphoresis
    • Dyspnea Dyspnea Dyspnea is the subjective sensation of breathing discomfort. Dyspnea is a normal manifestation of heavy physical or psychological exertion, but also may be caused by underlying conditions (both pulmonary and extrapulmonary). Dyspnea
    • Nausea Nausea An unpleasant sensation in the stomach usually accompanied by the urge to vomit. Common causes are early pregnancy, sea and motion sickness, emotional stress, intense pain, food poisoning, and various enteroviruses. Antiemetics
  • Associated symptoms:
  • Atypical presentation Presentation The position or orientation of the fetus at near term or during obstetric labor, determined by its relation to the spine of the mother and the birth canal. The normal position is a vertical, cephalic presentation with the fetal vertex flexed on the neck. Normal and Abnormal Labor more common in women, the elderly, or patients Patients Individuals participating in the health care system for the purpose of receiving therapeutic, diagnostic, or preventive procedures. Clinician–Patient Relationship with diabetes Diabetes Diabetes mellitus (DM) is a metabolic disease characterized by hyperglycemia and dysfunction of the regulation of glucose metabolism by insulin. Type 1 DM is diagnosed mostly in children and young adults as the result of autoimmune destruction of β cells in the pancreas and the resulting lack of insulin. Type 2 DM has a significant association with obesity and is characterized by insulin resistance. Diabetes Mellitus:
    • Absence of chest pain Chest Pain Chest pain is one of the most common and challenging complaints that may present in an inpatient and outpatient setting. The differential diagnosis of chest pain is large and includes cardiac, gastrointestinal, pulmonary, musculoskeletal, and psychiatric etiologies. Chest Pain or atypical locations/ quality Quality Activities and programs intended to assure or improve the quality of care in either a defined medical setting or a program. The concept includes the assessment or evaluation of the quality of care; identification of problems or shortcomings in the delivery of care; designing activities to overcome these deficiencies; and follow-up monitoring to ensure effectiveness of corrective steps. Quality Measurement and Improvement
    • May present with only the usual associated symptoms

Physical examination

  • Vitals: 
    • Tachycardia Tachycardia Abnormally rapid heartbeat, usually with a heart rate above 100 beats per minute for adults. Tachycardia accompanied by disturbance in the cardiac depolarization (cardiac arrhythmia) is called tachyarrhythmia. Sepsis in Children
    • Bradycardia Bradycardia Bradyarrhythmia is a rhythm in which the heart rate is less than 60/min. Bradyarrhythmia can be physiologic, without symptoms or hemodynamic change. Pathologic bradyarrhythmia results in reduced cardiac output and hemodynamic instability causing syncope, dizziness, or dyspnea. Bradyarrhythmias with right coronary artery Coronary Artery Truncus Arteriosus (RCA) occlusion (supplies the sinoatrial (SA) and atrioventricular (AV) nodes)
    • Hypotension Hypotension Hypotension is defined as low blood pressure, specifically < 90/60 mm Hg, and is most commonly a physiologic response. Hypotension may be mild, serious, or life threatening, depending on the cause. Hypotension
  • Cardiovascular:
    • S3 S3 Heart Sounds heart sound (early diastolic sound heard at the end of rapid ventricular filling Ventricular filling Cardiac Cycle)
    • S4 S4 Heart Sounds heart sound (late diastolic sound heard at the onset of atrial contraction)
    • Jugular venous distention: RCA occlusion → right-sided heart failure Heart Failure A heterogeneous condition in which the heart is unable to pump out sufficient blood to meet the metabolic need of the body. Heart failure can be caused by structural defects, functional abnormalities (ventricular dysfunction), or a sudden overload beyond its capacity. Chronic heart failure is more common than acute heart failure which results from sudden insult to cardiac function, such as myocardial infarction. Total Anomalous Pulmonary Venous Return (TAPVR) (HF)
    • Hepatic congestion: RCA occlusion → right-sided HF
  • Pulmonary edema Pulmonary edema Pulmonary edema is a condition caused by excess fluid within the lung parenchyma and alveoli as a consequence of a disease process. Based on etiology, pulmonary edema is classified as cardiogenic or noncardiogenic. Patients may present with progressive dyspnea, orthopnea, cough, or respiratory failure. Pulmonary Edema: left coronary artery Coronary Artery Truncus Arteriosus occlusion → left-sided HF:
    • Crackles/ rales Rales Respiratory Syncytial Virus
    • Wheezing Wheezing Wheezing is an abnormal breath sound characterized by a whistling noise that can be relatively high-pitched and shrill (more common) or coarse. Wheezing is produced by the movement of air through narrowed or compressed small (intrathoracic) airways. Wheezing
  • Skin Skin The skin, also referred to as the integumentary system, is the largest organ of the body. The skin is primarily composed of the epidermis (outer layer) and dermis (deep layer). The epidermis is primarily composed of keratinocytes that undergo rapid turnover, while the dermis contains dense layers of connective tissue. Skin: Structure and Functions:
    • Cool
    • Pale or cyanotic
    • Diaphoretic

Diagnosis

Patients Patients Individuals participating in the health care system for the purpose of receiving therapeutic, diagnostic, or preventive procedures. Clinician–Patient Relationship presenting with a history of acute chest pain Chest Pain Chest pain is one of the most common and challenging complaints that may present in an inpatient and outpatient setting. The differential diagnosis of chest pain is large and includes cardiac, gastrointestinal, pulmonary, musculoskeletal, and psychiatric etiologies. Chest Pain or suspicious atypical symptoms are evaluated with ECG ECG An electrocardiogram (ECG) is a graphic representation of the electrical activity of the heart plotted against time. Adhesive electrodes are affixed to the skin surface allowing measurement of cardiac impulses from many angles. The ECG provides 3-dimensional information about the conduction system of the heart, the myocardium, and other cardiac structures. Electrocardiogram (ECG). Cardiac Cardiac Total Anomalous Pulmonary Venous Return (TAPVR) troponin levels should be obtained within 10 minutes of the patient’s arrival in the ED. Abnormalities in both confirm the diagnosis of MI.

ECG ECG An electrocardiogram (ECG) is a graphic representation of the electrical activity of the heart plotted against time. Adhesive electrodes are affixed to the skin surface allowing measurement of cardiac impulses from many angles. The ECG provides 3-dimensional information about the conduction system of the heart, the myocardium, and other cardiac structures. Electrocardiogram (ECG)

  • Findings in STEMI and their evolution: 
    • Tall, peaked (hyperacute) T waves may be seen early in the course.
    • ≥ 1- mm MM Multiple myeloma (MM) is a malignant condition of plasma cells (activated B lymphocytes) primarily seen in the elderly. Monoclonal proliferation of plasma cells results in cytokine-driven osteoclastic activity and excessive secretion of IgG antibodies. Multiple Myeloma ST elevation in ≥ 2 contiguous leads
    • Reciprocal ST depression
    • New left bundle branch block Left bundle branch block Bundle Branch and Fascicular Blocks ( LBBB LBBB Bundle Branch and Fascicular Blocks) and symptoms → STEMI until proven otherwise
    • Pathologic Q waves typically emerge between 6 and 16 hours after symptom onset
    • T-wave inversion follows
    • ST-segment normalization
    • T-wave normalization over several hours to days
  • Findings in NSTEMI:
    • ST depression (not elevations)
    • Nonspecific changes
    • Inverted T waves
Table: Localization of STEMI on ECG ECG An electrocardiogram (ECG) is a graphic representation of the electrical activity of the heart plotted against time. Adhesive electrodes are affixed to the skin surface allowing measurement of cardiac impulses from many angles. The ECG provides 3-dimensional information about the conduction system of the heart, the myocardium, and other cardiac structures. Electrocardiogram (ECG)
Artery occluded Leads with ST elevation Location of MI
Proximal LAD V1–V2 Septal
LAD V3–V4 Anterior
Distal LAD V5–V6 Apical
LCX or LAD I, aVL Lateral
RCA (more common) or LCX II, III, aVF Inferior
RCA or LCX V7–V9 (ST depressions in V1–V3) Posterolateral
LAD: left anterior descending artery
LCX: left circumflex artery
RCA: right coronary artery Coronary Artery Truncus Arteriosus

Laboratory evaluation

Cardiac Cardiac Total Anomalous Pulmonary Venous Return (TAPVR) enzymes Enzymes Enzymes are complex protein biocatalysts that accelerate chemical reactions without being consumed by them. Due to the body’s constant metabolic needs, the absence of enzymes would make life unsustainable, as reactions would occur too slowly without these molecules. Basics of Enzymes

  • Structural proteins Structural proteins Proteins and Peptides in the heart that are released as a result of myocardial injury
  • Troponin I:
    • Serum levels:
      • Start to ↑ within 2–3 hours after the onset of chest pain Chest Pain Chest pain is one of the most common and challenging complaints that may present in an inpatient and outpatient setting. The differential diagnosis of chest pain is large and includes cardiac, gastrointestinal, pulmonary, musculoskeletal, and psychiatric etiologies. Chest Pain
      • Peak levels at 12–48 hours
      • Return to baseline over 4–10 days
    • Highest sensitivity Sensitivity Binary classification measures to assess test results. Sensitivity or recall rate is the proportion of true positives. Blotting Techniques and specificity Specificity Specificity is the probability of correctly determining the absence of a condition. Immunoassays (compared to other cardiac Cardiac Total Anomalous Pulmonary Venous Return (TAPVR) enzymes Enzymes Enzymes are complex protein biocatalysts that accelerate chemical reactions without being consumed by them. Due to the body’s constant metabolic needs, the absence of enzymes would make life unsustainable, as reactions would occur too slowly without these molecules. Basics of Enzymes)
    • Serial lab draws are used to assess for a rise and fall in levels (recheck in 1–3 hours).
    • The degree of ↑ correlates with the size of the infarct Infarct Area of necrotic cells in an organ, arising mainly from hypoxia and ischemia Ischemic Cell Damage.
    • Can be ↑ as the result of causes of coronary ischemia Ischemia A hypoperfusion of the blood through an organ or tissue caused by a pathologic constriction or obstruction of its blood vessels, or an absence of blood circulation. Ischemic Cell Damage other than acute MI:
      • Arrhythmia
      • Cocaine Cocaine An alkaloid ester extracted from the leaves of plants including coca. It is a local anesthetic and vasoconstrictor and is clinically used for that purpose, particularly in the eye, ear, nose, and throat. It also has powerful central nervous system effects similar to the amphetamines and is a drug of abuse. Cocaine, like amphetamines, acts by multiple mechanisms on brain catecholaminergic neurons; the mechanism of its reinforcing effects is thought to involve inhibition of dopamine uptake. Local Anesthetics
      • PCI PCI Penetrating chest injuries (PCI) are caused by an object puncturing the chest wall. Penetrating chest injuries can be high velocity, such as with gunshot wounds (GSWs); medium velocity, such as with pellet gunshots; or low velocity, such as with stab wounds. Penetrating Chest Injury
      • Coronary embolism
      • Aortic dissection Aortic dissection Aortic dissection occurs due to shearing stress from pulsatile pressure causing a tear in the tunica intima of the aortic wall. This tear allows blood to flow into the media, creating a “false lumen.” Aortic dissection is most commonly caused by uncontrolled hypertension. Aortic Dissection
    • Can be ↑ with noncoronary ischemia Ischemia A hypoperfusion of the blood through an organ or tissue caused by a pathologic constriction or obstruction of its blood vessels, or an absence of blood circulation. Ischemic Cell Damage or myocardial injury:
      • Electrical shock Shock Shock is a life-threatening condition associated with impaired circulation that results in tissue hypoxia. The different types of shock are based on the underlying cause: distributive (↑ cardiac output (CO), ↓ systemic vascular resistance (SVR)), cardiogenic (↓ CO, ↑ SVR), hypovolemic (↓ CO, ↑ SVR), obstructive (↓ CO), and mixed. Types of Shock
      • Hypoxia Hypoxia Sub-optimal oxygen levels in the ambient air of living organisms. Ischemic Cell Damage
      • Myocarditis Myocarditis Myocarditis is an inflammatory disease of the myocardium, which may occur alone or in association with a systemic process. There are numerous etiologies of myocarditis, but all lead to inflammation and myocyte injury, most often leading to signs and symptoms of heart failure. Myocarditis
      • Takotsubo cardiomyopathy Takotsubo Cardiomyopathy Takotsubo cardiomyopathy (also known as stress cardiomyopathy, or “broken heart syndrome”) is a type of non-ischemic cardiomyopathy in which there is transient regional systolic dysfunction of the left ventricle. Patients present with symptoms of acute coronary syndrome, including chest pressure and shortness of breath. Takotsubo Cardiomyopathy: sudden, temporary weakening of the heart muscle (usually related to a stressor)
    • Patients Patients Individuals participating in the health care system for the purpose of receiving therapeutic, diagnostic, or preventive procedures. Clinician–Patient Relationship with CKD CKD Chronic kidney disease (CKD) is kidney impairment that lasts for ≥ 3 months, implying that it is irreversible. Hypertension and diabetes are the most common causes; however, there are a multitude of other etiologies. In the early to moderate stages, CKD is usually asymptomatic and is primarily diagnosed by laboratory abnormalities. Chronic Kidney Disease:
      • May have stably ↑ levels in the absence of myocardial damage
      • A rise or fall in troponin I value > 20% over 6–9 hours is indicative of acute MI in patients Patients Individuals participating in the health care system for the purpose of receiving therapeutic, diagnostic, or preventive procedures. Clinician–Patient Relationship with end-stage CKD CKD Chronic kidney disease (CKD) is kidney impairment that lasts for ≥ 3 months, implying that it is irreversible. Hypertension and diabetes are the most common causes; however, there are a multitude of other etiologies. In the early to moderate stages, CKD is usually asymptomatic and is primarily diagnosed by laboratory abnormalities. Chronic Kidney Disease.
  • CK-MB isoenzyme: 
    • Less sensitive and specific than troponin
      • ↑ within 3–6 hours after chest pain Chest Pain Chest pain is one of the most common and challenging complaints that may present in an inpatient and outpatient setting. The differential diagnosis of chest pain is large and includes cardiac, gastrointestinal, pulmonary, musculoskeletal, and psychiatric etiologies. Chest Pain
      • Peaks within 12–24 hours
      • Normalizes 48–72 hours after MI
    • Continued ↑ after 72 hours is diagnostic of reinfarction.
    • The degree of ↑ in CK-MB correlates with the size of the infarct Infarct Area of necrotic cells in an organ, arising mainly from hypoxia and ischemia Ischemic Cell Damage.

Supporting labs: 

  • LDH LDH Osteosarcoma and AST AST Enzymes of the transferase class that catalyze the conversion of l-aspartate and 2-ketoglutarate to oxaloacetate and l-glutamate. Liver Function Tests → may be ↑, but no longer used in the diagnosis of MI.
  • BNP BNP A peptide that is secreted by the brain and the heart atria, stored mainly in cardiac ventricular myocardium. It can cause natriuresis; diuresis; vasodilation; and inhibits secretion of renin and aldosterone. It improves heart function. It contains 32 amino acids. Renal Sodium and Water Regulation → ↑ in heart failure Heart Failure A heterogeneous condition in which the heart is unable to pump out sufficient blood to meet the metabolic need of the body. Heart failure can be caused by structural defects, functional abnormalities (ventricular dysfunction), or a sudden overload beyond its capacity. Chronic heart failure is more common than acute heart failure which results from sudden insult to cardiac function, such as myocardial infarction. Total Anomalous Pulmonary Venous Return (TAPVR)
  • Potassium Potassium An element in the alkali group of metals with an atomic symbol k, atomic number 19, and atomic weight 39. 10. It is the chief cation in the intracellular fluid of muscle and other cells. Potassium ion is a strong electrolyte that plays a significant role in the regulation of fluid volume and maintenance of the water-electrolyte balance. Hyperkalemia and magnesium Magnesium A metallic element that has the atomic symbol mg, atomic number 12, and atomic weight 24. 31. It is important for the activity of many enzymes, especially those involved in oxidative phosphorylation. Electrolytes levels should be optimized during management.
  • Drug screen to evaluate for cocaine Cocaine An alkaloid ester extracted from the leaves of plants including coca. It is a local anesthetic and vasoconstrictor and is clinically used for that purpose, particularly in the eye, ear, nose, and throat. It also has powerful central nervous system effects similar to the amphetamines and is a drug of abuse. Cocaine, like amphetamines, acts by multiple mechanisms on brain catecholaminergic neurons; the mechanism of its reinforcing effects is thought to involve inhibition of dopamine uptake. Local Anesthetics or methamphetamine Methamphetamine A central nervous system stimulant and sympathomimetic with actions and uses similar to dextroamphetamine. The smokable form is a drug of abuse and is referred to as crank, crystal, crystal meth, ice, and speed. Stimulants use.

Comparison within acute coronary syndrome

The following table compares unstable angina Unstable angina Precordial pain at rest, which may precede a myocardial infarction. Stable and Unstable Angina, NSTEMI, and STEMI on the basis of clinical features, ECG ECG An electrocardiogram (ECG) is a graphic representation of the electrical activity of the heart plotted against time. Adhesive electrodes are affixed to the skin surface allowing measurement of cardiac impulses from many angles. The ECG provides 3-dimensional information about the conduction system of the heart, the myocardium, and other cardiac structures. Electrocardiogram (ECG), and laboratory findings.

Table: Comparison within acute coronary syndrome
Diagnosis Clinical features ECG ECG An electrocardiogram (ECG) is a graphic representation of the electrical activity of the heart plotted against time. Adhesive electrodes are affixed to the skin surface allowing measurement of cardiac impulses from many angles. The ECG provides 3-dimensional information about the conduction system of the heart, the myocardium, and other cardiac structures. Electrocardiogram (ECG) findings Laboratory findings
Unstable angina Unstable angina Precordial pain at rest, which may precede a myocardial infarction. Stable and Unstable Angina Ischemic chest pain Chest Pain Chest pain is one of the most common and challenging complaints that may present in an inpatient and outpatient setting. The differential diagnosis of chest pain is large and includes cardiac, gastrointestinal, pulmonary, musculoskeletal, and psychiatric etiologies. Chest Pain that occurs at rest or with previously tolerated levels of exertion
  • None
  • ST-segment depression
  • TWI
Normal troponin
NSTEMI Prolonged ischemic chest pain Chest Pain Chest pain is one of the most common and challenging complaints that may present in an inpatient and outpatient setting. The differential diagnosis of chest pain is large and includes cardiac, gastrointestinal, pulmonary, musculoskeletal, and psychiatric etiologies. Chest Pain in any setting
  • None
  • ST-segment depression
  • TWI
Elevated troponin
STEMI Prolonged ischemic chest pain Chest Pain Chest pain is one of the most common and challenging complaints that may present in an inpatient and outpatient setting. The differential diagnosis of chest pain is large and includes cardiac, gastrointestinal, pulmonary, musculoskeletal, and psychiatric etiologies. Chest Pain in any setting Elevated troponin
LBBB LBBB Bundle Branch and Fascicular Blocks: left bundle branch block Left bundle branch block Bundle Branch and Fascicular Blocks
TWI: T-wave inversion

Imaging

  • Chest X-ray X-ray Penetrating electromagnetic radiation emitted when the inner orbital electrons of an atom are excited and release radiant energy. X-ray wavelengths range from 1 pm to 10 nm. Hard x-rays are the higher energy, shorter wavelength x-rays. Soft x-rays or grenz rays are less energetic and longer in wavelength. The short wavelength end of the x-ray spectrum overlaps the gamma rays wavelength range. The distinction between gamma rays and x-rays is based on their radiation source. Pulmonary Function Tests
    • Should be done to evaluate for other causes of chest pain Chest Pain Chest pain is one of the most common and challenging complaints that may present in an inpatient and outpatient setting. The differential diagnosis of chest pain is large and includes cardiac, gastrointestinal, pulmonary, musculoskeletal, and psychiatric etiologies. Chest Pain, such as:
      • Pneumonia Pneumonia Pneumonia or pulmonary inflammation is an acute or chronic inflammation of lung tissue. Causes include infection with bacteria, viruses, or fungi. In more rare cases, pneumonia can also be caused through toxic triggers through inhalation of toxic substances, immunological processes, or in the course of radiotherapy. Pneumonia
      • Pneumothorax Pneumothorax A pneumothorax is a life-threatening condition in which air collects in the pleural space, causing partial or full collapse of the lung. A pneumothorax can be traumatic or spontaneous. Patients present with a sudden onset of sharp chest pain, dyspnea, and diminished breath sounds on exam. Pneumothorax
      • Mediastinal widening → aortic dissection Aortic dissection Aortic dissection occurs due to shearing stress from pulsatile pressure causing a tear in the tunica intima of the aortic wall. This tear allows blood to flow into the media, creating a “false lumen.” Aortic dissection is most commonly caused by uncontrolled hypertension. Aortic Dissection
    • May show pulmonary edema Pulmonary edema Pulmonary edema is a condition caused by excess fluid within the lung parenchyma and alveoli as a consequence of a disease process. Based on etiology, pulmonary edema is classified as cardiogenic or noncardiogenic. Patients may present with progressive dyspnea, orthopnea, cough, or respiratory failure. Pulmonary Edema heart failure Heart Failure A heterogeneous condition in which the heart is unable to pump out sufficient blood to meet the metabolic need of the body. Heart failure can be caused by structural defects, functional abnormalities (ventricular dysfunction), or a sudden overload beyond its capacity. Chronic heart failure is more common than acute heart failure which results from sudden insult to cardiac function, such as myocardial infarction. Total Anomalous Pulmonary Venous Return (TAPVR)
  • Coronary angiography Angiography Radiography of blood vessels after injection of a contrast medium. Cardiac Surgery:
    • Gold standard test
    • Findings:
      • Localizes narrowed or occluded coronary arteries Arteries Arteries are tubular collections of cells that transport oxygenated blood and nutrients from the heart to the tissues of the body. The blood passes through the arteries in order of decreasing luminal diameter, starting in the largest artery (the aorta) and ending in the small arterioles. Arteries are classified into 3 types: large elastic arteries, medium muscular arteries, and small arteries and arterioles. Arteries: Histology
      • New regional wall motion abnormalities consistent with an ischemic infarct Infarct Area of necrotic cells in an organ, arising mainly from hypoxia and ischemia Ischemic Cell Damage
      • Left ventriculography can assess left ventricular function.
  • Determines the need for intervention with stenting or surgery
  • Transthoracic echocardiography Echocardiography Ultrasonic recording of the size, motion, and composition of the heart and surrounding tissues. The standard approach is transthoracic. Tricuspid Valve Atresia (TVA):
    • Left ventricular ejection Ventricular ejection Cardiac Cycle fraction (LVEF) is the best predictor of survival in STEMI.
    • New regional wall motion abnormalities can be visualized
    • Can evaluate for complications of MI:
      • Free-wall rupture
      • Ventricular septal rupture
      • Mitral regurgitation Regurgitation Gastroesophageal Reflux Disease (GERD)
      • Aneurysm Aneurysm An aneurysm is a bulging, weakened area of a blood vessel that causes an abnormal widening of its diameter > 1.5 times the size of the native vessel. Aneurysms occur more often in arteries than in veins and are at risk of dissection and rupture, which can be life-threatening. Thoracic Aortic Aneurysms formation
      • Presence of a thrombus

Management

Initial therapy

Prompt recognition of the diagnosis of acute MI is imperative in order to realize the benefit from reperfusion therapy. 

  • Oxygen: previously used with every patient, currently used only if: 
    • O2 saturation < 90%
    • Respiratory distress present
    • Heart failure Heart Failure A heterogeneous condition in which the heart is unable to pump out sufficient blood to meet the metabolic need of the body. Heart failure can be caused by structural defects, functional abnormalities (ventricular dysfunction), or a sudden overload beyond its capacity. Chronic heart failure is more common than acute heart failure which results from sudden insult to cardiac function, such as myocardial infarction. Total Anomalous Pulmonary Venous Return (TAPVR) present
    • Other high-risk features of hypoxia Hypoxia Sub-optimal oxygen levels in the ambient air of living organisms. Ischemic Cell Damage
  • Treat ventricular arrhythmias (if present).
  • Aspirin Aspirin The prototypical analgesic used in the treatment of mild to moderate pain. It has anti-inflammatory and antipyretic properties and acts as an inhibitor of cyclooxygenase which results in the inhibition of the biosynthesis of prostaglandins. Aspirin also inhibits platelet aggregation and is used in the prevention of arterial and venous thrombosis. Nonsteroidal Antiinflammatory Drugs (NSAIDs):
  • Nitroglycerin Nitroglycerin A volatile vasodilator which relieves angina pectoris by stimulating guanylate cyclase and lowering cytosolic calcium. It is also sometimes used for tocolysis and explosives. Nitrates (sublingual):
    • Start if the patient still has chest pain Chest Pain Chest pain is one of the most common and challenging complaints that may present in an inpatient and outpatient setting. The differential diagnosis of chest pain is large and includes cardiac, gastrointestinal, pulmonary, musculoskeletal, and psychiatric etiologies. Chest Pain, hypertension Hypertension Hypertension, or high blood pressure, is a common disease that manifests as elevated systemic arterial pressures. Hypertension is most often asymptomatic and is found incidentally as part of a routine physical examination or during triage for an unrelated medical encounter. Hypertension, or heart failure Heart Failure A heterogeneous condition in which the heart is unable to pump out sufficient blood to meet the metabolic need of the body. Heart failure can be caused by structural defects, functional abnormalities (ventricular dysfunction), or a sudden overload beyond its capacity. Chronic heart failure is more common than acute heart failure which results from sudden insult to cardiac function, such as myocardial infarction. Total Anomalous Pulmonary Venous Return (TAPVR)
    • Vasodilation Vasodilation The physiological widening of blood vessels by relaxing the underlying vascular smooth muscle. Pulmonary Hypertension Drugs preload Preload Cardiac Mechanics → ↓ oxygen demand → ↓ symptoms
    • Add IV nitrates Nitrates Nitrates are a class of medications that cause systemic vasodilation (veins > arteries) by smooth muscle relaxation. Nitrates are primarily indicated for the treatment of angina, where preferential venodilation causes pooling of blood, decreased preload, and ultimately decreased myocardial O2 demand. Nitrates if symptoms persist after 3 sublingual doses
    • Avoid in patients Patients Individuals participating in the health care system for the purpose of receiving therapeutic, diagnostic, or preventive procedures. Clinician–Patient Relationship with:
  • Beta-blockers Beta-blockers Drugs that bind to but do not activate beta-adrenergic receptors thereby blocking the actions of beta-adrenergic agonists. Adrenergic beta-antagonists are used for treatment of hypertension, cardiac arrhythmias, angina pectoris, glaucoma, migraine headaches, and anxiety. Class 2 Antiarrhythmic Drugs (Beta Blockers):
    • Heart rate Heart rate The number of times the heart ventricles contract per unit of time, usually per minute. Cardiac Physiology and contractility → ↓ oxygen demand→ ↓ symptoms
    • Mortality Mortality All deaths reported in a given population. Measures of Health Status
    • Contraindicated if the patient has:
      • Heart failure Heart Failure A heterogeneous condition in which the heart is unable to pump out sufficient blood to meet the metabolic need of the body. Heart failure can be caused by structural defects, functional abnormalities (ventricular dysfunction), or a sudden overload beyond its capacity. Chronic heart failure is more common than acute heart failure which results from sudden insult to cardiac function, such as myocardial infarction. Total Anomalous Pulmonary Venous Return (TAPVR)
      • Bradycardia Bradycardia Bradyarrhythmia is a rhythm in which the heart rate is less than 60/min. Bradyarrhythmia can be physiologic, without symptoms or hemodynamic change. Pathologic bradyarrhythmia results in reduced cardiac output and hemodynamic instability causing syncope, dizziness, or dyspnea. Bradyarrhythmias
      • Severe reactive airway Airway ABCDE Assessment disease
      • Cocaine Cocaine An alkaloid ester extracted from the leaves of plants including coca. It is a local anesthetic and vasoconstrictor and is clinically used for that purpose, particularly in the eye, ear, nose, and throat. It also has powerful central nervous system effects similar to the amphetamines and is a drug of abuse. Cocaine, like amphetamines, acts by multiple mechanisms on brain catecholaminergic neurons; the mechanism of its reinforcing effects is thought to involve inhibition of dopamine uptake. Local Anesthetics-induced MI
  • Morphine Morphine The principal alkaloid in opium and the prototype opiate analgesic and narcotic. Morphine has widespread effects in the central nervous system and on smooth muscle. Opioid Analgesics:
  • Treat heart failure Heart Failure A heterogeneous condition in which the heart is unable to pump out sufficient blood to meet the metabolic need of the body. Heart failure can be caused by structural defects, functional abnormalities (ventricular dysfunction), or a sudden overload beyond its capacity. Chronic heart failure is more common than acute heart failure which results from sudden insult to cardiac function, such as myocardial infarction. Total Anomalous Pulmonary Venous Return (TAPVR) with diuretics Diuretics Agents that promote the excretion of urine through their effects on kidney function. Heart Failure and Angina Medication (if present).
  • Start high-dose statin therapy (e.g., atorvastatin Atorvastatin A pyrrole and heptanoic acid derivative, hydroxymethylglutaryl-CoA reductase inhibitor (statin), and anticholesteremic agent that is used to reduce serum levels of ldl-cholesterol; apolipoprotein b; and triglycerides. It is used to increase serum levels of hdl-cholesterol in the treatment of hyperlipidemias, and for the prevention of cardiovascular diseases in patients with multiple risk factors. Statins) as early as possible and before PCI PCI Penetrating chest injuries (PCI) are caused by an object puncturing the chest wall. Penetrating chest injuries can be high velocity, such as with gunshot wounds (GSWs); medium velocity, such as with pellet gunshots; or low velocity, such as with stab wounds. Penetrating Chest Injury.
  • IV saline to ↑ cardiac Cardiac Total Anomalous Pulmonary Venous Return (TAPVR) output and perfusion with right ventricular MI
  • Anticoagulation Anticoagulation Pulmonary Hypertension Drugs recommendations vary with the clinical situation and plan for PCI PCI Penetrating chest injuries (PCI) are caused by an object puncturing the chest wall. Penetrating chest injuries can be high velocity, such as with gunshot wounds (GSWs); medium velocity, such as with pellet gunshots; or low velocity, such as with stab wounds. Penetrating Chest Injury or thrombolytic therapy: 
    • Heparin
    • Low-molecular-weight heparin (LMWH)

Risk stratification

  • Important for prognosis Prognosis A prediction of the probable outcome of a disease based on a individual’s condition and the usual course of the disease as seen in similar situations. Non-Hodgkin Lymphomas
    • Patients Patients Individuals participating in the health care system for the purpose of receiving therapeutic, diagnostic, or preventive procedures. Clinician–Patient Relationship at the highest risk for further cardiac Cardiac Total Anomalous Pulmonary Venous Return (TAPVR) events may benefit from a more aggressive therapeutic approach:
      • Risk scores such as TIMI (Thrombolysis in Myocardial Infarction), Global Registry of Acute Coronary Events (GRACE), or Platelet Glycoprotein IIb/IIIa in  Unstable Angina Unstable angina Precordial pain at rest, which may precede a myocardial infarction. Stable and Unstable Angina: Receptor Receptor Receptors are proteins located either on the surface of or within a cell that can bind to signaling molecules known as ligands (e.g., hormones) and cause some type of response within the cell. Receptors Suppression Suppression Defense Mechanisms Using  Integrilin Integrilin Cyclic peptide that acts as a platelet glycoprotein iib-iiia antagonist, reversibly inhibiting the binding of fibrinogen; von Willebrand factor; and other adhesive molecules to the gpiib-iiia receptors of platelets. It is used in the management of unstable angina and in patients undergoing coronary angioplasty and stenting procedures. Antiplatelet Drugs Therapy (PURSUIT) have good predictive ability.
      • These scoring systems take into account markers of predictive outcome for prognosis Prognosis A prediction of the probable outcome of a disease based on a individual’s condition and the usual course of the disease as seen in similar situations. Non-Hodgkin Lymphomas.
    • End points for predictive outcome:
  • TIMI risk scores help in decision-making for urgent revascularization Revascularization Thromboangiitis Obliterans (Buerger’s Disease):
    • Based on:
      • ECG ECG An electrocardiogram (ECG) is a graphic representation of the electrical activity of the heart plotted against time. Adhesive electrodes are affixed to the skin surface allowing measurement of cardiac impulses from many angles. The ECG provides 3-dimensional information about the conduction system of the heart, the myocardium, and other cardiac structures. Electrocardiogram (ECG) features
      • Elevated cardiac Cardiac Total Anomalous Pulmonary Venous Return (TAPVR) enzymes Enzymes Enzymes are complex protein biocatalysts that accelerate chemical reactions without being consumed by them. Due to the body’s constant metabolic needs, the absence of enzymes would make life unsustainable, as reactions would occur too slowly without these molecules. Basics of Enzymes
      • Evidence of hemodynamic instability
      • Persistent chest pain Chest Pain Chest pain is one of the most common and challenging complaints that may present in an inpatient and outpatient setting. The differential diagnosis of chest pain is large and includes cardiac, gastrointestinal, pulmonary, musculoskeletal, and psychiatric etiologies. Chest Pain despite appropriate medical therapy
      • Age
      • Comorbidities Comorbidities The presence of co-existing or additional diseases with reference to an initial diagnosis or with reference to the index condition that is the subject of study. Comorbidity may affect the ability of affected individuals to function and also their survival; it may be used as a prognostic indicator for length of hospital stay, cost factors, and outcome or survival. St. Louis Encephalitis Virus (other CHD risk factors)
      • Recent aspirin Aspirin The prototypical analgesic used in the treatment of mild to moderate pain. It has anti-inflammatory and antipyretic properties and acts as an inhibitor of cyclooxygenase which results in the inhibition of the biosynthesis of prostaglandins. Aspirin also inhibits platelet aggregation and is used in the prevention of arterial and venous thrombosis. Nonsteroidal Antiinflammatory Drugs (NSAIDs) use
    • For TIMI score > 3 with NSTEMI or unstable angina Unstable angina Precordial pain at rest, which may precede a myocardial infarction. Stable and Unstable Angina, revascularization Revascularization Thromboangiitis Obliterans (Buerger’s Disease) with PCI PCI Penetrating chest injuries (PCI) are caused by an object puncturing the chest wall. Penetrating chest injuries can be high velocity, such as with gunshot wounds (GSWs); medium velocity, such as with pellet gunshots; or low velocity, such as with stab wounds. Penetrating Chest Injury is recommended:
      • Low risk: score of 0–2
      • Intermediate risk: score of 3–4
      • High risk: score of 5–7 

Reperfusion

  • PCI PCI Penetrating chest injuries (PCI) are caused by an object puncturing the chest wall. Penetrating chest injuries can be high velocity, such as with gunshot wounds (GSWs); medium velocity, such as with pellet gunshots; or low velocity, such as with stab wounds. Penetrating Chest Injury:
    • Indications:
      • STEMI
      • NSTEMI with TIMI score > 3
    • ↓ Amount of myocardial damage
    • Mortality Mortality All deaths reported in a given population. Measures of Health Status 
    • For patients Patients Individuals participating in the health care system for the purpose of receiving therapeutic, diagnostic, or preventive procedures. Clinician–Patient Relationship who present ≤ 2 hours after the onset of symptoms → PCI PCI Penetrating chest injuries (PCI) are caused by an object puncturing the chest wall. Penetrating chest injuries can be high velocity, such as with gunshot wounds (GSWs); medium velocity, such as with pellet gunshots; or low velocity, such as with stab wounds. Penetrating Chest Injury with drug-eluting stent to prevent restenosis, if available:
      • Improves survival
      • ↓ Rate of intracranial hemorrhage Intracranial hemorrhage Subarachnoid hemorrhage (SAH) is a type of cerebrovascular accident (stroke) resulting from intracranial hemorrhage into the subarachnoid space between the arachnoid and the pia mater layers of the meninges surrounding the brain. Most sahs originate from a saccular aneurysm in the circle of willis but may also occur as a result of trauma, uncontrolled hypertension, vasculitis, anticoagulant use, or stimulant use. Subarachnoid Hemorrhage and recurrent MI as compared with fibrinolysis
  • If PCI PCI Penetrating chest injuries (PCI) are caused by an object puncturing the chest wall. Penetrating chest injuries can be high velocity, such as with gunshot wounds (GSWs); medium velocity, such as with pellet gunshots; or low velocity, such as with stab wounds. Penetrating Chest Injury is not readily available, then thrombolytic agents are recommended for reperfusion:
    • Tenecteplase Tenecteplase A tissue plasminogen activator enzyme that acts as a fibrinolytic agent; it is used for the dissolution of blood clots, such as those that occur in acute myocardial infarction. Thrombolytics and reteplase Reteplase Thrombolytics ( fibrin Fibrin A protein derived from fibrinogen in the presence of thrombin, which forms part of the blood clot. Rapidly Progressive Glomerulonephritis-specific) are preferred.
    • Streptokinase Streptokinase Streptococcal fibrinolysin. An enzyme produced by hemolytic streptococci. It hydrolyzes amide linkages and serves as an activator of plasminogen. It is used in thrombolytic therapy and is used also in mixtures with streptodornase (streptodornase and streptokinase). Thrombolytics and alteplase Alteplase Thrombolytics are other options.
    • Consider fibrinolytic therapy in patients Patients Individuals participating in the health care system for the purpose of receiving therapeutic, diagnostic, or preventive procedures. Clinician–Patient Relationship with ≤ 12 hours of symptoms.
    • All are contraindicated with active bleeding, recent stroke, or suspected aortic dissection Aortic dissection Aortic dissection occurs due to shearing stress from pulsatile pressure causing a tear in the tunica intima of the aortic wall. This tear allows blood to flow into the media, creating a “false lumen.” Aortic dissection is most commonly caused by uncontrolled hypertension. Aortic Dissection.
  • For patients Patients Individuals participating in the health care system for the purpose of receiving therapeutic, diagnostic, or preventive procedures. Clinician–Patient Relationship with symptoms > 2–3 hours:
    • Transfer for primary PCI PCI Penetrating chest injuries (PCI) are caused by an object puncturing the chest wall. Penetrating chest injuries can be high velocity, such as with gunshot wounds (GSWs); medium velocity, such as with pellet gunshots; or low velocity, such as with stab wounds. Penetrating Chest Injury if available within 120 minutes (including transfer time).
    • Start dual antiplatelet therapy: aspirin Aspirin The prototypical analgesic used in the treatment of mild to moderate pain. It has anti-inflammatory and antipyretic properties and acts as an inhibitor of cyclooxygenase which results in the inhibition of the biosynthesis of prostaglandins. Aspirin also inhibits platelet aggregation and is used in the prevention of arterial and venous thrombosis. Nonsteroidal Antiinflammatory Drugs (NSAIDs) plus P2Y12 inhibitors ( clopidogrel Clopidogrel A ticlopidine analog and platelet purinergic p2y receptor antagonist that inhibits adenosine diphosphate-mediated platelet aggregation. It is used to prevent thromboembolism in patients with arterial occlusive diseases; myocardial infarction; stroke; or atrial fibrillation. Antiplatelet Drugs, prasugrel Prasugrel A piperazine derivative and platelet aggregation inhibitor that is used to prevent thrombosis in patients with acute coronary syndrome; unstable angina and myocardial infarction, as well as in those undergoing percutaneous coronary interventions. Antiplatelet Drugs, ticagrelor Ticagrelor An adenosine triphosphate analogue and reversible p2y12 purinoceptor antagonist that inhibits adp-mediated platelet aggregation. It is used for the prevention of thromboembolism by patients with acute coronary syndrome or a history of myocardial infarction. Antiplatelet Drugs).
    • Glycoprotein IIb/IIIa inhibitors (e.g., abciximab) 
  • Indications for CABG CABG Surgical therapy of ischemic coronary artery disease achieved by grafting a section of saphenous vein, internal mammary artery, or other substitute between the aorta and the obstructed coronary artery distal to the obstructive lesion. Cardiac Surgery surgery after MI:
    • Failure of thrombolytics Thrombolytics Thrombolytics, also known as fibrinolytics, include recombinant tissue plasminogen activator (TPa) (i.e., alteplase, reteplase, and tenecteplase), urokinase, and streptokinase. The agents promote the breakdown of a blood clot by converting plasminogen to plasmin, which then degrades fibrin. Thrombolytics or PCI PCI Penetrating chest injuries (PCI) are caused by an object puncturing the chest wall. Penetrating chest injuries can be high velocity, such as with gunshot wounds (GSWs); medium velocity, such as with pellet gunshots; or low velocity, such as with stab wounds. Penetrating Chest Injury to reperfuse damaged myocardium Myocardium The muscle tissue of the heart. It is composed of striated, involuntary muscle cells connected to form the contractile pump to generate blood flow. Heart: Anatomy
    • Hemodynamically important mechanical complications (e.g., rupture)
    • Anatomy not amenable to PCI PCI Penetrating chest injuries (PCI) are caused by an object puncturing the chest wall. Penetrating chest injuries can be high velocity, such as with gunshot wounds (GSWs); medium velocity, such as with pellet gunshots; or low velocity, such as with stab wounds. Penetrating Chest Injury

Post-MI care

Improved long-term prognosis Prognosis A prediction of the probable outcome of a disease based on a individual’s condition and the usual course of the disease as seen in similar situations. Non-Hodgkin Lymphomas is seen with:

  • Antiplatelet therapy to ↓ the risk of recurrent coronary artery Coronary Artery Truncus Arteriosus thrombosis Thrombosis Formation and development of a thrombus or blood clot in the blood vessel. Epidemic Typhus or, with PCI PCI Penetrating chest injuries (PCI) are caused by an object puncturing the chest wall. Penetrating chest injuries can be high velocity, such as with gunshot wounds (GSWs); medium velocity, such as with pellet gunshots; or low velocity, such as with stab wounds. Penetrating Chest Injury, coronary artery Coronary Artery Truncus Arteriosus stent thrombosis Thrombosis Formation and development of a thrombus or blood clot in the blood vessel. Epidemic Typhus
  • ACEi ACEi A class of drugs whose main indications are the treatment of hypertension and heart failure. They exert their hemodynamic effect mainly by inhibiting the renin-angiotensin system. They also modulate sympathetic nervous system activity and increase prostaglandin synthesis. They cause mainly vasodilation and mild natriuresis without affecting heart rate and contractility. Renin-Angiotensin-Aldosterone System Inhibitors therapy to prevent remodeling of the left ventricle
  • Statin therapy
  • Anticoagulation Anticoagulation Pulmonary Hypertension Drugs in the presence of left ventricular thrombus or chronic atrial fibrillation Atrial fibrillation Atrial fibrillation (AF or Afib) is a supraventricular tachyarrhythmia and the most common kind of arrhythmia. It is caused by rapid, uncontrolled atrial contractions and uncoordinated ventricular responses. Atrial Fibrillation to prevent embolization Embolization A method of hemostasis utilizing various agents such as gelfoam, silastic, metal, glass, or plastic pellets, autologous clot, fat, and muscle as emboli. It has been used in the treatment of spinal cord and intracranial arteriovenous malformations, renal arteriovenous fistulas, gastrointestinal bleeding, epistaxis, hypersplenism, certain highly vascular tumors, traumatic rupture of blood vessels, and control of operative hemorrhage. Gastrointestinal Bleeding

Complications

After MI, different risks develop as time passes after the acute event. Patients Patients Individuals participating in the health care system for the purpose of receiving therapeutic, diagnostic, or preventive procedures. Clinician–Patient Relationship with type 2 Type 2 Spinal Muscular Atrophy MI have a higher prevalence Prevalence The total number of cases of a given disease in a specified population at a designated time. It is differentiated from incidence, which refers to the number of new cases in the population at a given time. Measures of Disease Frequency of heart failure Heart Failure A heterogeneous condition in which the heart is unable to pump out sufficient blood to meet the metabolic need of the body. Heart failure can be caused by structural defects, functional abnormalities (ventricular dysfunction), or a sudden overload beyond its capacity. Chronic heart failure is more common than acute heart failure which results from sudden insult to cardiac function, such as myocardial infarction. Total Anomalous Pulmonary Venous Return (TAPVR), kidney disease as a complication of MI, and atrial fibrillation Atrial fibrillation Atrial fibrillation (AF or Afib) is a supraventricular tachyarrhythmia and the most common kind of arrhythmia. It is caused by rapid, uncontrolled atrial contractions and uncoordinated ventricular responses. Atrial Fibrillation.

  • Death: 1 of 3 patients Patients Individuals participating in the health care system for the purpose of receiving therapeutic, diagnostic, or preventive procedures. Clinician–Patient Relationship do not survive their initial MI.
  • Potential complications in the first 1–3 days post-MI:
    • Ventricular arrhythmia (most common cause of death)
    • Acute heart failure Heart Failure A heterogeneous condition in which the heart is unable to pump out sufficient blood to meet the metabolic need of the body. Heart failure can be caused by structural defects, functional abnormalities (ventricular dysfunction), or a sudden overload beyond its capacity. Chronic heart failure is more common than acute heart failure which results from sudden insult to cardiac function, such as myocardial infarction. Total Anomalous Pulmonary Venous Return (TAPVR)
    • Cardiogenic shock Cardiogenic shock Shock resulting from diminution of cardiac output in heart disease. Types of Shock
    • Pericarditis Pericarditis Pericarditis is an inflammation of the pericardium, often with fluid accumulation. It can be caused by infection (often viral), myocardial infarction, drugs, malignancies, metabolic disorders, autoimmune disorders, or trauma. Acute, subacute, and chronic forms exist. Pericarditis:
      • Pleuritic chest pain Chest Pain Chest pain is one of the most common and challenging complaints that may present in an inpatient and outpatient setting. The differential diagnosis of chest pain is large and includes cardiac, gastrointestinal, pulmonary, musculoskeletal, and psychiatric etiologies. Chest Pain that increases with lying supine
      • Pericardial rub on auscultation
      • Fever Fever Fever is defined as a measured body temperature of at least 38°C (100.4°F). Fever is caused by circulating endogenous and/or exogenous pyrogens that increase levels of prostaglandin E2 in the hypothalamus. Fever is commonly associated with chills, rigors, sweating, and flushing of the skin. Fever
      • Dry cough Dry Cough Strongyloidiasis
      • ECG ECG An electrocardiogram (ECG) is a graphic representation of the electrical activity of the heart plotted against time. Adhesive electrodes are affixed to the skin surface allowing measurement of cardiac impulses from many angles. The ECG provides 3-dimensional information about the conduction system of the heart, the myocardium, and other cardiac structures. Electrocardiogram (ECG) showing diffuse ST elevations
      • Pericardial effusion Pericardial effusion Fluid accumulation within the pericardium. Serous effusions are associated with pericardial diseases. Hemopericardium is associated with trauma. Lipid-containing effusion (chylopericardium) results from leakage of thoracic duct. Severe cases can lead to cardiac tamponade. Pericardial Effusion and Cardiac Tamponade seen on echocardiogram Echocardiogram Transposition of the Great Vessels
  • 3–14 days post-MI:
    • Free-wall rupture: 
      • Can result in cardiac Cardiac Total Anomalous Pulmonary Venous Return (TAPVR) tamponade Tamponade Pericardial effusion, usually of rapid onset, exceeding ventricular filling pressures and causing collapse of the heart with a markedly reduced cardiac output. Pericarditis or pseudoaneurysm Pseudoaneurysm Not an aneurysm but a well-defined collection of blood and connective tissue outside the wall of a blood vessel or the heart. It is the containment of a ruptured blood vessel or heart, such as sealing a rupture of the left ventricle. False aneurysm is formed by organized thrombus and hematoma in surrounding tissue. Thoracic Aortic Aneurysms formation
      • Incidence Incidence The number of new cases of a given disease during a given period in a specified population. It also is used for the rate at which new events occur in a defined population. It is differentiated from prevalence, which refers to all cases in the population at a given time. Measures of Disease Frequency is highest during macrophage-mediated removal of necrotic myocardium Myocardium The muscle tissue of the heart. It is composed of striated, involuntary muscle cells connected to form the contractile pump to generate blood flow. Heart: Anatomy.
    • Papillary muscle rupture:
      • Posteromedial papillary muscle rupture due to posterior descending artery occlusion
      • Posteromedial-wall rupture → acute mitral regurgitation Acute mitral regurgitation Mitral Regurgitation
      • Holosystolic murmur Holosystolic Murmur Tricuspid Valve Atresia (TVA) over the 5th intercostal space at the midclavicular line
      • May present with signs of left-sided heart failure Heart Failure A heterogeneous condition in which the heart is unable to pump out sufficient blood to meet the metabolic need of the body. Heart failure can be caused by structural defects, functional abnormalities (ventricular dysfunction), or a sudden overload beyond its capacity. Chronic heart failure is more common than acute heart failure which results from sudden insult to cardiac function, such as myocardial infarction. Total Anomalous Pulmonary Venous Return (TAPVR) ( pulmonary edema Pulmonary edema Pulmonary edema is a condition caused by excess fluid within the lung parenchyma and alveoli as a consequence of a disease process. Based on etiology, pulmonary edema is classified as cardiogenic or noncardiogenic. Patients may present with progressive dyspnea, orthopnea, cough, or respiratory failure. Pulmonary Edema, crackles, dyspnea Dyspnea Dyspnea is the subjective sensation of breathing discomfort. Dyspnea is a normal manifestation of heavy physical or psychological exertion, but also may be caused by underlying conditions (both pulmonary and extrapulmonary). Dyspnea)
    • Ventricular septal rupture:
      • Caused by left anterior descending artery occlusion
      • Coincides with macrophage infiltration of the wall
      • May present as a holosystolic murmur Holosystolic Murmur Tricuspid Valve Atresia (TVA) over the left sternal border 
      • May present with signs of right-sided heart failure Heart Failure A heterogeneous condition in which the heart is unable to pump out sufficient blood to meet the metabolic need of the body. Heart failure can be caused by structural defects, functional abnormalities (ventricular dysfunction), or a sudden overload beyond its capacity. Chronic heart failure is more common than acute heart failure which results from sudden insult to cardiac function, such as myocardial infarction. Total Anomalous Pulmonary Venous Return (TAPVR) (e.g., jugular venous distention, peripheral edema Peripheral edema Peripheral edema is the swelling of the lower extremities, namely, legs, feet, and ankles. Edema) or biventricular failure
      • May progress to cardiogenic shock Cardiogenic shock Shock resulting from diminution of cardiac output in heart disease. Types of Shock due to a ↓ in cardiac Cardiac Total Anomalous Pulmonary Venous Return (TAPVR) output
    • Mural thrombus formation with potential embolization Embolization A method of hemostasis utilizing various agents such as gelfoam, silastic, metal, glass, or plastic pellets, autologous clot, fat, and muscle as emboli. It has been used in the treatment of spinal cord and intracranial arteriovenous malformations, renal arteriovenous fistulas, gastrointestinal bleeding, epistaxis, hypersplenism, certain highly vascular tumors, traumatic rupture of blood vessels, and control of operative hemorrhage. Gastrointestinal Bleeding of the clot can lead to:
      • Limb ischemia Ischemia A hypoperfusion of the blood through an organ or tissue caused by a pathologic constriction or obstruction of its blood vessels, or an absence of blood circulation. Ischemic Cell Damage
      • Stroke
      • Mesenteric ischemia Mesenteric Ischemia Mesenteric ischemia is a rare, life-threatening condition caused by inadequate blood flow through the mesenteric vessels, which results in ischemia and necrosis of the intestinal wall. Mesenteric ischemia can be either acute or chronic. Mesenteric Ischemia
      • Renal infarction Renal Infarction Imaging of the Urinary System
  • > 14 days post-MI:
    • Dressler syndrome:
      • Autoimmune sensitization to antigens released during cardiomyocyte death 
      • Presents with signs of pericarditis Pericarditis Pericarditis is an inflammation of the pericardium, often with fluid accumulation. It can be caused by infection (often viral), myocardial infarction, drugs, malignancies, metabolic disorders, autoimmune disorders, or trauma. Acute, subacute, and chronic forms exist. Pericarditis (e.g., pleuritic pain Pleuritic Pain Pneumothorax, friction rub, fever Fever Fever is defined as a measured body temperature of at least 38°C (100.4°F). Fever is caused by circulating endogenous and/or exogenous pyrogens that increase levels of prostaglandin E2 in the hypothalamus. Fever is commonly associated with chills, rigors, sweating, and flushing of the skin. Fever
      • May result in elevation of troponins and leukocytosis Leukocytosis A transient increase in the number of leukocytes in a body fluid. West Nile Virus
      • ECG ECG An electrocardiogram (ECG) is a graphic representation of the electrical activity of the heart plotted against time. Adhesive electrodes are affixed to the skin surface allowing measurement of cardiac impulses from many angles. The ECG provides 3-dimensional information about the conduction system of the heart, the myocardium, and other cardiac structures. Electrocardiogram (ECG) shows diffuse ST elevations
      • Pericardial effusion Pericardial effusion Fluid accumulation within the pericardium. Serous effusions are associated with pericardial diseases. Hemopericardium is associated with trauma. Lipid-containing effusion (chylopericardium) results from leakage of thoracic duct. Severe cases can lead to cardiac tamponade. Pericardial Effusion and Cardiac Tamponade: abnormal amount of fluid in the pericardial cavity Pericardial cavity Heart: Anatomy of the heart 
      • Can be complicated by cardiac Cardiac Total Anomalous Pulmonary Venous Return (TAPVR) tamponade Tamponade Pericardial effusion, usually of rapid onset, exceeding ventricular filling pressures and causing collapse of the heart with a markedly reduced cardiac output. Pericarditis/hemopericardium
    • Ventricular aneurysm Aneurysm An aneurysm is a bulging, weakened area of a blood vessel that causes an abnormal widening of its diameter > 1.5 times the size of the native vessel. Aneurysms occur more often in arteries than in veins and are at risk of dissection and rupture, which can be life-threatening. Thoracic Aortic Aneurysms presenting with: 
      • Persistent ST elevations and T-wave inversions > 3 weeks post-MI
      • Signs of angina (e.g., dyspnea Dyspnea Dyspnea is the subjective sensation of breathing discomfort. Dyspnea is a normal manifestation of heavy physical or psychological exertion, but also may be caused by underlying conditions (both pulmonary and extrapulmonary). Dyspnea on exertion)
      • Systolic murmur and/or S3 S3 Heart Sounds/ S4 S4 Heart Sounds sounds

Differential Diagnosis

  • Unstable angina Unstable angina Precordial pain at rest, which may precede a myocardial infarction. Stable and Unstable Angina: presents with chest pain Chest Pain Chest pain is one of the most common and challenging complaints that may present in an inpatient and outpatient setting. The differential diagnosis of chest pain is large and includes cardiac, gastrointestinal, pulmonary, musculoskeletal, and psychiatric etiologies. Chest Pain due to transient myocardial ischemia Ischemia A hypoperfusion of the blood through an organ or tissue caused by a pathologic constriction or obstruction of its blood vessels, or an absence of blood circulation. Ischemic Cell Damage and may be a warning sign for the risk of heart attack (MI) in the future. Diagnosis is by history and examination, ECG ECG An electrocardiogram (ECG) is a graphic representation of the electrical activity of the heart plotted against time. Adhesive electrodes are affixed to the skin surface allowing measurement of cardiac impulses from many angles. The ECG provides 3-dimensional information about the conduction system of the heart, the myocardium, and other cardiac structures. Electrocardiogram (ECG), and stress testing, with possible additional nuclear medicine Nuclear medicine A specialty field of radiology concerned with diagnostic, therapeutic, and investigative use of radioactive compounds. Nuclear Imaging imaging, echocardiography Echocardiography Ultrasonic recording of the size, motion, and composition of the heart and surrounding tissues. The standard approach is transthoracic. Tricuspid Valve Atresia (TVA), or coronary angiography Angiography Radiography of blood vessels after injection of a contrast medium. Cardiac Surgery. Troponin will be normal. Treatment includes antiplatelet medications, nitrates Nitrates Nitrates are a class of medications that cause systemic vasodilation (veins > arteries) by smooth muscle relaxation. Nitrates are primarily indicated for the treatment of angina, where preferential venodilation causes pooling of blood, decreased preload, and ultimately decreased myocardial O2 demand. Nitrates, statins Statins Statins are competitive inhibitors of HMG-CoA reductase in the liver. HMG-CoA reductase is the rate-limiting step in cholesterol synthesis. Inhibition results in lowered intrahepatocytic cholesterol formation, resulting in up-regulation of LDL receptors and, ultimately, lowering levels of serum LDL and triglycerides. Statins, beta-blockers Beta-blockers Drugs that bind to but do not activate beta-adrenergic receptors thereby blocking the actions of beta-adrenergic agonists. Adrenergic beta-antagonists are used for treatment of hypertension, cardiac arrhythmias, angina pectoris, glaucoma, migraine headaches, and anxiety. Class 2 Antiarrhythmic Drugs (Beta Blockers), and PCI PCI Penetrating chest injuries (PCI) are caused by an object puncturing the chest wall. Penetrating chest injuries can be high velocity, such as with gunshot wounds (GSWs); medium velocity, such as with pellet gunshots; or low velocity, such as with stab wounds. Penetrating Chest Injury.
  • Vasospastic angina Vasospastic Angina Vasospastic angina, also known as Prinzmetal or variant angina, is an uncommon cause of chest pain due to transient coronary artery spasms. The pathophysiology is distinguished from stable or unstable angina secondary to atherosclerotic coronary artery disease (CAD). Vasospastic Angina: uncommon cause of chest pain Chest Pain Chest pain is one of the most common and challenging complaints that may present in an inpatient and outpatient setting. The differential diagnosis of chest pain is large and includes cardiac, gastrointestinal, pulmonary, musculoskeletal, and psychiatric etiologies. Chest Pain due to transient coronary artery Coronary Artery Truncus Arteriosus spasms Spasms An involuntary contraction of a muscle or group of muscles. Spasms may involve skeletal muscle or smooth muscle. Ion Channel Myopathy. The clinical presentation Presentation The position or orientation of the fetus at near term or during obstetric labor, determined by its relation to the spine of the mother and the birth canal. The normal position is a vertical, cephalic presentation with the fetal vertex flexed on the neck. Normal and Abnormal Labor of vasospastic angina Vasospastic Angina Vasospastic angina, also known as Prinzmetal or variant angina, is an uncommon cause of chest pain due to transient coronary artery spasms. The pathophysiology is distinguished from stable or unstable angina secondary to atherosclerotic coronary artery disease (CAD). Vasospastic Angina is characterized by spontaneous episodes of chest pain Chest Pain Chest pain is one of the most common and challenging complaints that may present in an inpatient and outpatient setting. The differential diagnosis of chest pain is large and includes cardiac, gastrointestinal, pulmonary, musculoskeletal, and psychiatric etiologies. Chest Pain due to a transient decrease in blood flow Flow Blood flows through the heart, arteries, capillaries, and veins in a closed, continuous circuit. Flow is the movement of volume per unit of time. Flow is affected by the pressure gradient and the resistance fluid encounters between 2 points. Vascular resistance is the opposition to flow, which is caused primarily by blood friction against vessel walls. Vascular Resistance, Flow, and Mean Arterial Pressure to the epicardial arteries Arteries Arteries are tubular collections of cells that transport oxygenated blood and nutrients from the heart to the tissues of the body. The blood passes through the arteries in order of decreasing luminal diameter, starting in the largest artery (the aorta) and ending in the small arterioles. Arteries are classified into 3 types: large elastic arteries, medium muscular arteries, and small arteries and arterioles. Arteries: Histology. Diagnosis is made by clinical history, normal exam, and ECG ECG An electrocardiogram (ECG) is a graphic representation of the electrical activity of the heart plotted against time. Adhesive electrodes are affixed to the skin surface allowing measurement of cardiac impulses from many angles. The ECG provides 3-dimensional information about the conduction system of the heart, the myocardium, and other cardiac structures. Electrocardiogram (ECG). Cardiac Cardiac Total Anomalous Pulmonary Venous Return (TAPVR) enzymes Enzymes Enzymes are complex protein biocatalysts that accelerate chemical reactions without being consumed by them. Due to the body’s constant metabolic needs, the absence of enzymes would make life unsustainable, as reactions would occur too slowly without these molecules. Basics of Enzymes and PCI PCI Penetrating chest injuries (PCI) are caused by an object puncturing the chest wall. Penetrating chest injuries can be high velocity, such as with gunshot wounds (GSWs); medium velocity, such as with pellet gunshots; or low velocity, such as with stab wounds. Penetrating Chest Injury are usually normal. Management includes the prevention of vasospasm with calcium channel blockers Calcium Channel Blockers Calcium channel blockers (CCBs) are a class of medications that inhibit voltage-dependent L-type calcium channels of cardiac and vascular smooth muscle cells. The inhibition of these channels produces vasodilation and myocardial depression. There are 2 major classes of CCBs: dihydropyridines and non-dihydropyridines. Class 4 Antiarrhythmic Drugs (Calcium Channel Blockers) and the relief of angina with nitrates Nitrates Nitrates are a class of medications that cause systemic vasodilation (veins > arteries) by smooth muscle relaxation. Nitrates are primarily indicated for the treatment of angina, where preferential venodilation causes pooling of blood, decreased preload, and ultimately decreased myocardial O2 demand. Nitrates
  • Aortic dissection Aortic dissection Aortic dissection occurs due to shearing stress from pulsatile pressure causing a tear in the tunica intima of the aortic wall. This tear allows blood to flow into the media, creating a “false lumen.” Aortic dissection is most commonly caused by uncontrolled hypertension. Aortic Dissection: due to shearing stress from pulsatile pressure causing a tear in the tunica intima Tunica intima The innermost layer of an artery or vein, made up of one layer of endothelial cells and supported by an internal elastic lamina. Arteries: Histology of the aortic wall, often associated with hypertension Hypertension Hypertension, or high blood pressure, is a common disease that manifests as elevated systemic arterial pressures. Hypertension is most often asymptomatic and is found incidentally as part of a routine physical examination or during triage for an unrelated medical encounter. Hypertension. Patients Patients Individuals participating in the health care system for the purpose of receiving therapeutic, diagnostic, or preventive procedures. Clinician–Patient Relationship with aortic dissection Aortic dissection Aortic dissection occurs due to shearing stress from pulsatile pressure causing a tear in the tunica intima of the aortic wall. This tear allows blood to flow into the media, creating a “false lumen.” Aortic dissection is most commonly caused by uncontrolled hypertension. Aortic Dissection often present with acute, tearing chest or back pain Back pain Back pain is a common complaint among the general population and is mostly self-limiting. Back pain can be classified as acute, subacute, or chronic depending on the duration of symptoms. The wide variety of potential etiologies include degenerative, mechanical, malignant, infectious, rheumatologic, and extraspinal causes. Back Pain. Diagnosis is made by CT imaging. Type A dissections (in the ascending aorta Ascending aorta Mediastinum and Great Vessels: Anatomy) are a surgical emergency Surgical Emergency Acute Abdomen because of the risk of imminent rupture. Type B dissections (in the descending aorta Descending aorta Mediastinum and Great Vessels: Anatomy) can often be managed medically with beta-blockers Beta-blockers Drugs that bind to but do not activate beta-adrenergic receptors thereby blocking the actions of beta-adrenergic agonists. Adrenergic beta-antagonists are used for treatment of hypertension, cardiac arrhythmias, angina pectoris, glaucoma, migraine headaches, and anxiety. Class 2 Antiarrhythmic Drugs (Beta Blockers) and calcium channel blockers Calcium Channel Blockers Calcium channel blockers (CCBs) are a class of medications that inhibit voltage-dependent L-type calcium channels of cardiac and vascular smooth muscle cells. The inhibition of these channels produces vasodilation and myocardial depression. There are 2 major classes of CCBs: dihydropyridines and non-dihydropyridines. Class 4 Antiarrhythmic Drugs (Calcium Channel Blockers)
  • Pulmonary embolism Pulmonary Embolism Pulmonary embolism (PE) is a potentially fatal condition that occurs as a result of intraluminal obstruction of the main pulmonary artery or its branches. The causative factors include thrombi, air, amniotic fluid, and fat. In PE, gas exchange is impaired due to the decreased return of deoxygenated blood to the lungs. Pulmonary Embolism: presents with pleuritic pain Pleuritic Pain Pneumothorax, dyspnea Dyspnea Dyspnea is the subjective sensation of breathing discomfort. Dyspnea is a normal manifestation of heavy physical or psychological exertion, but also may be caused by underlying conditions (both pulmonary and extrapulmonary). Dyspnea, tachycardia Tachycardia Abnormally rapid heartbeat, usually with a heart rate above 100 beats per minute for adults. Tachycardia accompanied by disturbance in the cardiac depolarization (cardiac arrhythmia) is called tachyarrhythmia. Sepsis in Children, and occasionally chest pain Chest Pain Chest pain is one of the most common and challenging complaints that may present in an inpatient and outpatient setting. The differential diagnosis of chest pain is large and includes cardiac, gastrointestinal, pulmonary, musculoskeletal, and psychiatric etiologies. Chest Pain. Risk factors for pulmonary embolism Pulmonary Embolism Pulmonary embolism (PE) is a potentially fatal condition that occurs as a result of intraluminal obstruction of the main pulmonary artery or its branches. The causative factors include thrombi, air, amniotic fluid, and fat. In PE, gas exchange is impaired due to the decreased return of deoxygenated blood to the lungs. Pulmonary Embolism are prolonged immobilization Immobilization Delirium, oral contraceptives or estrogen therapy Estrogen therapy The use of hormonal agents with estrogen-like activity in postmenopausal or other estrogen-deficient women to alleviate effects of hormone deficiency, such as vasomotor symptoms, dyspareunia, and progressive development of osteoporosis. This may also include the use of progestational agents in combination therapy. Menopause, smoking Smoking Willful or deliberate act of inhaling and exhaling smoke from burning substances or agents held by hand. Interstitial Lung Diseases, and obesity Obesity Obesity is a condition associated with excess body weight, specifically with the deposition of excessive adipose tissue. Obesity is considered a global epidemic. Major influences come from the western diet and sedentary lifestyles, but the exact mechanisms likely include a mixture of genetic and environmental factors. Obesity. Diagnosis of venous thromboembolism Thromboembolism Obstruction of a blood vessel (embolism) by a blood clot (thrombus) in the blood stream. Systemic Lupus Erythematosus is made by CT. ECG ECG An electrocardiogram (ECG) is a graphic representation of the electrical activity of the heart plotted against time. Adhesive electrodes are affixed to the skin surface allowing measurement of cardiac impulses from many angles. The ECG provides 3-dimensional information about the conduction system of the heart, the myocardium, and other cardiac structures. Electrocardiogram (ECG) may be normal or may show ST-segment changes. Management is urgent, with anticoagulation Anticoagulation Pulmonary Hypertension Drugs to prevent further propagation Propagation Propagation refers to how the electrical signal spreads to every myocyte in the heart. Cardiac Physiology of the clot.
  • Pericarditis Pericarditis Pericarditis is an inflammation of the pericardium, often with fluid accumulation. It can be caused by infection (often viral), myocardial infarction, drugs, malignancies, metabolic disorders, autoimmune disorders, or trauma. Acute, subacute, and chronic forms exist. Pericarditis: inflammatory disorder of the pericardium Pericardium A conical fibroserous sac surrounding the heart and the roots of the great vessels (aorta; venae cavae; pulmonary artery). Pericardium consists of two sacs: the outer fibrous pericardium and the inner serous pericardium. The latter consists of an outer parietal layer facing the fibrous pericardium, and an inner visceral layer (epicardium) resting next to the heart, and a pericardial cavity between these two layers. Heart: Anatomy resulting in chest pain Chest Pain Chest pain is one of the most common and challenging complaints that may present in an inpatient and outpatient setting. The differential diagnosis of chest pain is large and includes cardiac, gastrointestinal, pulmonary, musculoskeletal, and psychiatric etiologies. Chest Pain that is usually constant and may manifest with diffuse ST-segment elevation on ECG ECG An electrocardiogram (ECG) is a graphic representation of the electrical activity of the heart plotted against time. Adhesive electrodes are affixed to the skin surface allowing measurement of cardiac impulses from many angles. The ECG provides 3-dimensional information about the conduction system of the heart, the myocardium, and other cardiac structures. Electrocardiogram (ECG). Etiologies can be infectious Infectious Febrile Infant (usually viral), post-MI, due to medications, or due to malignancy Malignancy Hemothorax. Treatment is supportive if viral or with management of the underlying cause.
  • Costochondritis: due to inflammation Inflammation Inflammation is a complex set of responses to infection and injury involving leukocytes as the principal cellular mediators in the body’s defense against pathogenic organisms. Inflammation is also seen as a response to tissue injury in the process of wound healing. The 5 cardinal signs of inflammation are pain, heat, redness, swelling, and loss of function. Inflammation of the cartilage Cartilage Cartilage is a type of connective tissue derived from embryonic mesenchyme that is responsible for structural support, resilience, and the smoothness of physical actions. Perichondrium (connective tissue membrane surrounding cartilage) compensates for the absence of vasculature in cartilage by providing nutrition and support. Cartilage: Histology in the rib cage Rib cage The bony thoracic enclosure consisting of the vertebral column; the ribs; the sternum; and the costal cartilage. Chest Wall: Anatomy. Costochondritis presents with chest pain Chest Pain Chest pain is one of the most common and challenging complaints that may present in an inpatient and outpatient setting. The differential diagnosis of chest pain is large and includes cardiac, gastrointestinal, pulmonary, musculoskeletal, and psychiatric etiologies. Chest Pain that is reproducible on palpation Palpation Application of fingers with light pressure to the surface of the body to determine consistency of parts beneath in physical diagnosis; includes palpation for determining the outlines of organs. Dermatologic Examination. It may be due to trauma, strain, or viral infection. Diagnosis is made clinically and by the exclusion of coronary disease with appropriate testing. Treatment is with local measures and NSAIDs NSAIDS Primary vs Secondary Headaches.
  • Esophageal spasm: painful contraction of the esophagus Esophagus The esophagus is a muscular tube-shaped organ of around 25 centimeters in length that connects the pharynx to the stomach. The organ extends from approximately the 6th cervical vertebra to the 11th thoracic vertebra and can be divided grossly into 3 parts: the cervical part, the thoracic part, and the abdominal part. Esophagus: Anatomy that can present with severe, intermittent chest pain Chest Pain Chest pain is one of the most common and challenging complaints that may present in an inpatient and outpatient setting. The differential diagnosis of chest pain is large and includes cardiac, gastrointestinal, pulmonary, musculoskeletal, and psychiatric etiologies. Chest Pain. Diagnosis is by ruling out cardiac Cardiac Total Anomalous Pulmonary Venous Return (TAPVR) causes of chest pain Chest Pain Chest pain is one of the most common and challenging complaints that may present in an inpatient and outpatient setting. The differential diagnosis of chest pain is large and includes cardiac, gastrointestinal, pulmonary, musculoskeletal, and psychiatric etiologies. Chest Pain, esophageal manometry Manometry Measurement of the pressure or tension of liquids or gases with a manometer. Achalasia, and a barium swallow Barium Swallow Imaging of the Intestines study. Management may include antispasmodic Antispasmodic Antispasmodics are a group of medications used to reduce excessive GI smooth muscle contractility and spasm. These medications may be helpful in those with abdominal pain due to conditions such as irritable bowel syndrome, although their efficacy is controversial. Antispasmodics medications and, in some cases, surgery.
  • Takotsubo cardiomyopathy Takotsubo Cardiomyopathy Takotsubo cardiomyopathy (also known as stress cardiomyopathy, or “broken heart syndrome”) is a type of non-ischemic cardiomyopathy in which there is transient regional systolic dysfunction of the left ventricle. Patients present with symptoms of acute coronary syndrome, including chest pressure and shortness of breath. Takotsubo Cardiomyopathy: type of nonischemic cardiomyopathy Cardiomyopathy Cardiomyopathy refers to a group of myocardial diseases associated with structural changes of the heart muscles (myocardium) and impaired systolic and/or diastolic function in the absence of other heart disorders (coronary artery disease, hypertension, valvular disease, and congenital heart disease). Cardiomyopathy: Overview and Types in which there is transient regional systolic dysfunction Systolic dysfunction Dilated Cardiomyopathy of the left ventricle. Patients Patients Individuals participating in the health care system for the purpose of receiving therapeutic, diagnostic, or preventive procedures. Clinician–Patient Relationship present with symptoms of acute coronary syndrome, including chest pressure and shortness of breath Shortness of breath Dyspnea is the subjective sensation of breathing discomfort. Dyspnea is a normal manifestation of heavy physical or psychological exertion, but also may be caused by underlying conditions (both pulmonary and extrapulmonary). Dyspnea. ECG ECG An electrocardiogram (ECG) is a graphic representation of the electrical activity of the heart plotted against time. Adhesive electrodes are affixed to the skin surface allowing measurement of cardiac impulses from many angles. The ECG provides 3-dimensional information about the conduction system of the heart, the myocardium, and other cardiac structures. Electrocardiogram (ECG) may show ST-segment elevations. Coronary angiography Angiography Radiography of blood vessels after injection of a contrast medium. Cardiac Surgery will not show obstructed arteries Arteries Arteries are tubular collections of cells that transport oxygenated blood and nutrients from the heart to the tissues of the body. The blood passes through the arteries in order of decreasing luminal diameter, starting in the largest artery (the aorta) and ending in the small arterioles. Arteries are classified into 3 types: large elastic arteries, medium muscular arteries, and small arteries and arterioles. Arteries: Histology. Echocardiography Echocardiography Ultrasonic recording of the size, motion, and composition of the heart and surrounding tissues. The standard approach is transthoracic. Tricuspid Valve Atresia (TVA) will demonstrate characteristic apical wall motion abnormalities. Treatment includes beta-blockers Beta-blockers Drugs that bind to but do not activate beta-adrenergic receptors thereby blocking the actions of beta-adrenergic agonists. Adrenergic beta-antagonists are used for treatment of hypertension, cardiac arrhythmias, angina pectoris, glaucoma, migraine headaches, and anxiety. Class 2 Antiarrhythmic Drugs (Beta Blockers) and the removal of inciting stressors.
  • Myocarditis Myocarditis Myocarditis is an inflammatory disease of the myocardium, which may occur alone or in association with a systemic process. There are numerous etiologies of myocarditis, but all lead to inflammation and myocyte injury, most often leading to signs and symptoms of heart failure. Myocarditis: inflammatory disease of the myocardium Myocardium The muscle tissue of the heart. It is composed of striated, involuntary muscle cells connected to form the contractile pump to generate blood flow. Heart: Anatomy that can mimic an acute MI, especially in younger patients Patients Individuals participating in the health care system for the purpose of receiving therapeutic, diagnostic, or preventive procedures. Clinician–Patient Relationship (< 45 years). It may occur alone or in association with a systemic process. There are numerous etiologies, but all lead to inflammation Inflammation Inflammation is a complex set of responses to infection and injury involving leukocytes as the principal cellular mediators in the body’s defense against pathogenic organisms. Inflammation is also seen as a response to tissue injury in the process of wound healing. The 5 cardinal signs of inflammation are pain, heat, redness, swelling, and loss of function. Inflammation and myocyte injury. The diagnosis is supported by clinical findings, laboratory evaluation, and cardiac Cardiac Total Anomalous Pulmonary Venous Return (TAPVR) imaging. Management is supportive and aimed at addressing complications.

References

  1. Reeder, G.S., Kennedy, H.L. (2021). Diagnosis of acute myocardial infarction. UpToDate. Retrieved May 24, 2021, from https://www.uptodate.com/contents/diagnosis-of-acute-myocardial-infarction
  2. Thygesen, K., et al. (2018). Fourth universal definition of myocardial infarction (2018). Journal of the American College of Cardiology 72:2231–2264. https://doi.org/10.1016/j.jacc.2018.08.1038
  3. Simons, M., Breall, J.A. (2021). Overview of the acute management of non-ST-elevation acute coronary syndromes. UpToDate. Retrieved May 24, 2021, from https://www.uptodate.com/contents/overview-of-the-acute-management-of-non-st-elevation-acute-coronary-syndromes
  4. Reeder, G.S., Kennedy, H.L. (2021). Overview of the acute management of ST-elevation myocardial infarction. UpToDate. Retrieved May 24, 2021, from https://www.uptodate.com/contents/overview-of-the-acute-management-of-st-elevation-myocardial-infarction
  5. Rafla, S., Kamal, A. (2020). Localization of the occluded vessel in acute myocardial infarction. Journal of Cardiology and Cardiovascular Medicine 5:29–33. https://doi.org/10.29328/journal.jccm.1001082
  6. Sweis, R.N., Jivan, A. (2020). Acute myocardial infarction (MI). MSD Manual Professional Version. Retrieved June 12, 2021, from https://www.msdmanuals.com/professional/cardiovascular-disorders/coronary-artery-disease/acute-myocardial-infarction-mi
  7. Ojha, N., Dhamoon, A.S. (2020). Myocardial infarction. StatPearls. Retrieved June 12, 2021, from https://www.ncbi.nlm.nih.gov/books/NBK537076/
  8. Patibandla, S., Gupta, K., Alsayouri, K. (2020). Cardiac enzymes. StatPearls. Retrieved June 12, 2021, from https://www.ncbi.nlm.nih.gov/books/NBK545216/
  9. Stark, M., Kerndt, C.C., Sharma, S. (2021). Troponin. StatPearls. Retrieved June 12, 2021, from https://www.ncbi.nlm.nih.gov/books/NBK507805/
  10. Zafari, A.M., Abdou, M.H. (2019). Myocardial infarction. In Yang, E.H. (Ed.), Medscape. Retrieved June 12, 2021, from https://emedicine.medscape.com/article/155919-overview

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