Atrial Fibrillation

Atrial Fibrillation

Atrial fibrillation (AF or Afib) is a supraventricular tachyarrhythmia Tachyarrhythmia A tachyarrhythmia is a rapid heart rhythm, regular or irregular, with a rate > 100 beats/min. Tachyarrhythmia may or may not be accompanied by symptoms of hemodynamic change. Tachyarrhythmias and the most common kind of arrhythmia. It is caused by rapid, uncontrolled atrial contractions and uncoordinated ventricular responses. There are many conditions that can cause AF, usually damage to the heart (e.g., coronary artery Coronary Artery Truncus Arteriosus disease, previous myocardial infarction Myocardial infarction MI is ischemia and death of an area of myocardial tissue due to insufficient blood flow and oxygenation, usually from thrombus formation on a ruptured atherosclerotic plaque in the epicardial arteries. Clinical presentation is most commonly with chest pain, but women and patients with diabetes may have atypical symptoms. Myocardial Infarction). Diagnosis is confirmed by an electrocardiogram Electrocardiogram 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) that will show an “irregularly irregular” heartbeat with no distinct P waves and narrow QRS complexes. AF increases the risk of thromboembolic events. Treatment is primarily based on ventricular rate and rhythm control, which can be achieved through drugs and/or cardioversion. Anticoagulation Anticoagulation Pulmonary Hypertension Drugs is administered if the patient is at significant risk for thromboembolic events.

Last updated: May 27, 2025

Editorial responsibility: Stanley Oiseth, Lindsay Jones, Evelin Maza

Contents

Epidemiology and Etiology

Pathophysiology and Classification

Clinical Presentation

Diagnosis

Management

Differential Diagnosis

Epidemiology and Etiology

Epidemiology

Most common form of cardiac arrhythmia
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 increases with age
70% of patients Patients Individuals participating in the health care system for the purpose of receiving therapeutic, diagnostic, or preventive procedures. Clinician–Patient Relationship with atrial fibrillation (AF) are > 65 years old
More common in men (but if affected, women are more likely to be symptomatic and develop complications)
More common in Caucasians than African Americans, Hispanics, and Asians

General risk factors for cardiovascular disease

Advanced age
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
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 mellitus
Smoking Smoking Willful or deliberate act of inhaling and exhaling smoke from burning substances or agents held by hand. Interstitial Lung Diseases
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
Sleep apnea Sleep apnea Repeated cessation of breathing for > 10 seconds during sleep and results in sleep interruption, fatigue, and daytime sleepiness. Obstructive Sleep Apnea

Risk factors for AF

Usually associated with some underlying heart disease
Most common chronic disease associations are hypertensive heart disease and 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
15%–30% of cases are idiopathic Idiopathic Dermatomyositis or not associated with any known risk factor

Cardiac risk factors	Non-cardiac risk factors
Myocardial infarction Myocardial infarction MI is ischemia and death of an area of myocardial tissue due to insufficient blood flow and oxygenation, usually from thrombus formation on a ruptured atherosclerotic plaque in the epicardial arteries. Clinical presentation is most commonly with chest pain, but women and patients with diabetes may have atypical symptoms. Myocardial Infarction Coronary artery Coronary Artery Truncus Arteriosus disease 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) 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 (specifically hypertrophic) Other arrhythmias Valvular heart disease Congenital heart disease 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 Wolff-Parkinson-White syndrome Wolff-Parkinson-White Syndrome A form of ventricular pre-excitation characterized by a short PR interval and a long QRS interval with a delta wave. In this syndrome, atrial impulses are abnormally conducted to the heart ventricles via an accessory conducting pathway that is located between the wall of the right or left atria and the ventricles, also known as a bundle of kent. The inherited form can be caused by mutation of prkag2 gene encoding a gamma-2 regulatory subunit of amp-activated protein kinase. Supraventricular Tachycardias (WPW)	Electrolyte disturbances (e.g., hypokalemia Hypokalemia Hypokalemia is defined as plasma potassium (K+) concentration < 3.5 mEq/L. Homeostatic mechanisms maintain plasma concentration between 3.5-5.2 mEq/L despite marked variation in dietary intake. Hypokalemia can be due to renal losses, GI losses, transcellular shifts, or poor dietary intake. Hypokalemia) 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 Drugs (e.g., theophylline Theophylline A methyl xanthine derivative from tea with diuretic, smooth muscle relaxant, bronchial dilation, cardiac and central nervous system stimulant activities. Theophylline inhibits the 3. Asthma Drugs, adenosine Adenosine A nucleoside that is composed of adenine and d-ribose. Adenosine or adenosine derivatives play many important biological roles in addition to being components of DNA and RNA. Adenosine itself is a neurotransmitter. Class 5 Antiarrhythmic Drugs, digoxin Digoxin A cardiotonic glycoside obtained mainly from digitalis lanata; it consists of three sugars and the aglycone digoxigenin. Digoxin has positive inotropic and negative chronotropic activity. It is used to control ventricular rate in atrial fibrillation and in the management of congestive heart failure with atrial fibrillation. Its use in congestive heart failure and sinus rhythm is less certain. The margin between toxic and therapeutic doses is small. Cardiac Glycosides) Surgery (e.g., coronary artery Coronary Artery Truncus Arteriosus bypass grafting, valvular repair) 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 Hyperthyroidism Hyperthyroidism Hypersecretion of thyroid hormones from the thyroid gland. Elevated levels of thyroid hormones increase basal metabolic rate. Thyrotoxicosis and Hyperthyroidism Hypothermia Hypothermia Hypothermia can be defined as a drop in the core body temperature below 35°C (95°F) and is classified into mild, moderate, severe, and profound forms based on the degree of temperature decrease. Hypothermia Pulmonary causes: chronic obstructive pulmonary disease Pulmonary disease Diseases involving the respiratory system. Blastomyces/Blastomycosis ( COPD COPD Chronic obstructive pulmonary disease (COPD) is a lung disease characterized by progressive, largely irreversible airflow obstruction. The condition usually presents in middle-aged or elderly persons with a history of cigarette smoking. Signs and symptoms include prolonged expiration, wheezing, diminished breath sounds, progressive dyspnea, and chronic cough. Chronic Obstructive Pulmonary Disease (COPD)), 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 Chronic kidney disease Chronic Kidney Disease 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 Excessive sympathetic stimulation: Pheochromocytoma Pheochromocytoma Pheochromocytoma is a catecholamine-secreting tumor derived from chromaffin cells. The majority of tumors originate in the adrenal medulla, but they may also arise from sympathetic ganglia (also referred to as paraganglioma). Symptoms are associated with excessive catecholamine production and commonly include hypertension, tachycardia, headache, and sweating. Pheochromocytoma 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 amphetamines Amphetamines Analogs or derivatives of amphetamine. Many are sympathomimetics and central nervous system stimulators causing excitation, vasopressin, bronchodilation, and to varying degrees, anorexia, analepsis, nasal decongestion, and some smooth muscle relaxation. Stimulants Sepsis Sepsis Systemic inflammatory response syndrome with a proven or suspected infectious etiology. When sepsis is associated with organ dysfunction distant from the site of infection, it is called severe sepsis. When sepsis is accompanied by hypotension despite adequate fluid infusion, it is called septic shock. Sepsis and Septic Shock Heavy alcohol use (e.g., holiday heart syndrome) Metabolic syndrome Metabolic syndrome Metabolic syndrome is a cluster of conditions that significantly increases the risk for several secondary diseases, notably cardiovascular disease, type 2 diabetes, and nonalcoholic fatty liver. In general, it is agreed that hypertension, insulin resistance/hyperglycemia, and hyperlipidemia, along with central obesity, are components of the metabolic syndrome. Metabolic Syndrome

Cardiac risk factors

Non-cardiac risk factors

Myocardial infarction Myocardial infarction MI is ischemia and death of an area of myocardial tissue due to insufficient blood flow and oxygenation, usually from thrombus formation on a ruptured atherosclerotic plaque in the epicardial arteries. Clinical presentation is most commonly with chest pain, but women and patients with diabetes may have atypical symptoms. Myocardial Infarction
Coronary artery Coronary Artery Truncus Arteriosus disease
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)
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 (specifically hypertrophic)
Other arrhythmias
Valvular heart disease
Congenital heart disease
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
Wolff-Parkinson-White syndrome Wolff-Parkinson-White Syndrome A form of ventricular pre-excitation characterized by a short PR interval and a long QRS interval with a delta wave. In this syndrome, atrial impulses are abnormally conducted to the heart ventricles via an accessory conducting pathway that is located between the wall of the right or left atria and the ventricles, also known as a bundle of kent. The inherited form can be caused by mutation of prkag2 gene encoding a gamma-2 regulatory subunit of amp-activated protein kinase. Supraventricular Tachycardias (WPW)

Electrolyte disturbances (e.g., hypokalemia Hypokalemia Hypokalemia is defined as plasma potassium (K+) concentration < 3.5 mEq/L. Homeostatic mechanisms maintain plasma concentration between 3.5-5.2 mEq/L despite marked variation in dietary intake. Hypokalemia can be due to renal losses, GI losses, transcellular shifts, or poor dietary intake. Hypokalemia)
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
Drugs (e.g., theophylline Theophylline A methyl xanthine derivative from tea with diuretic, smooth muscle relaxant, bronchial dilation, cardiac and central nervous system stimulant activities. Theophylline inhibits the 3. Asthma Drugs, adenosine Adenosine A nucleoside that is composed of adenine and d-ribose. Adenosine or adenosine derivatives play many important biological roles in addition to being components of DNA and RNA. Adenosine itself is a neurotransmitter. Class 5 Antiarrhythmic Drugs, digoxin Digoxin A cardiotonic glycoside obtained mainly from digitalis lanata; it consists of three sugars and the aglycone digoxigenin. Digoxin has positive inotropic and negative chronotropic activity. It is used to control ventricular rate in atrial fibrillation and in the management of congestive heart failure with atrial fibrillation. Its use in congestive heart failure and sinus rhythm is less certain. The margin between toxic and therapeutic doses is small. Cardiac Glycosides)
Surgery (e.g., coronary artery Coronary Artery Truncus Arteriosus bypass grafting, valvular repair)
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
Hyperthyroidism Hyperthyroidism Hypersecretion of thyroid hormones from the thyroid gland. Elevated levels of thyroid hormones increase basal metabolic rate. Thyrotoxicosis and Hyperthyroidism
Hypothermia Hypothermia Hypothermia can be defined as a drop in the core body temperature below 35°C (95°F) and is classified into mild, moderate, severe, and profound forms based on the degree of temperature decrease. Hypothermia
Pulmonary causes: chronic obstructive pulmonary disease Pulmonary disease Diseases involving the respiratory system. Blastomyces/Blastomycosis ( COPD COPD Chronic obstructive pulmonary disease (COPD) is a lung disease characterized by progressive, largely irreversible airflow obstruction. The condition usually presents in middle-aged or elderly persons with a history of cigarette smoking. Signs and symptoms include prolonged expiration, wheezing, diminished breath sounds, progressive dyspnea, and chronic cough. Chronic Obstructive Pulmonary Disease (COPD)), 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
Chronic kidney disease Chronic Kidney Disease 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
Excessive sympathetic stimulation:
- Pheochromocytoma Pheochromocytoma Pheochromocytoma is a catecholamine-secreting tumor derived from chromaffin cells. The majority of tumors originate in the adrenal medulla, but they may also arise from sympathetic ganglia (also referred to as paraganglioma). Symptoms are associated with excessive catecholamine production and commonly include hypertension, tachycardia, headache, and sweating. Pheochromocytoma
- 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 amphetamines Amphetamines Analogs or derivatives of amphetamine. Many are sympathomimetics and central nervous system stimulators causing excitation, vasopressin, bronchodilation, and to varying degrees, anorexia, analepsis, nasal decongestion, and some smooth muscle relaxation. Stimulants
- Sepsis Sepsis Systemic inflammatory response syndrome with a proven or suspected infectious etiology. When sepsis is associated with organ dysfunction distant from the site of infection, it is called severe sepsis. When sepsis is accompanied by hypotension despite adequate fluid infusion, it is called septic shock. Sepsis and Septic Shock
Heavy alcohol use (e.g., holiday heart syndrome)
Metabolic syndrome Metabolic syndrome Metabolic syndrome is a cluster of conditions that significantly increases the risk for several secondary diseases, notably cardiovascular disease, type 2 diabetes, and nonalcoholic fatty liver. In general, it is agreed that hypertension, insulin resistance/hyperglycemia, and hyperlipidemia, along with central obesity, are components of the metabolic syndrome. Metabolic Syndrome

**Mnemonic: Etiology of acute AF = PIRATES**
P	Pulmonary diseases: Obstructive sleep apnea Pulmonary embolism COPD Pneumonia
I	Ischemia (CAD) Infarction ( MI MI MI is ischemia and death of an area of myocardial tissue due to insufficient blood flow and oxygenation, usually from thrombus formation on a ruptured atherosclerotic plaque in the epicardial arteries. Clinical presentation is most commonly with chest pain, but women and patients with diabetes may have atypical symptoms. Myocardial Infarction)
R	Rheumatic heart disease Mitral regurgitation
A	Anemia Atrial myxoma Myxoma A benign neoplasm derived from connective tissue, consisting chiefly of polyhedral and stellate cells that are loosely embedded in a soft mucoid matrix, thereby resembling primitive mesenchymal tissue. It occurs frequently intramuscularly where it may be mistaken for a sarcoma. It appears also in the jaws and the skin. Cardiac Myxoma Alcohol
T	Thyrotoxicosis Toxins
E	Ethanol Electrolytes Endocarditis
S	Sepsis Sick sinus syndrome

Pathophysiology and Classification

Pathophysiology

AF is caused by re-entrant electric conduction.
Re-entrant pathways can be due to:
- Fibrosed tissue
- Atrial dilation (e.g., congenital defect, post-MI, valvular disease, hypertensive heart disease)
- Abnormal accessory pathways (e.g., WPW syndrome)
Most common site of the rapid atrial firing that triggers AF is the pulmonary veins Pulmonary veins The veins that return the oxygenated blood from the lungs to the left atrium of the heart. Lungs: Anatomy.

Re-entrant phenomena — The pathophysiology of re-entrant pathways

An ectopic focus initiates a cardiac action potential, which travels in the form of a unidirectional conduction wave. If a conduction barrier is present (e.g., cardiac tissue damaged by ischemia), the wave will travel around it.

In healthy tissue, the conductive wave will meet refractory tissue upon completing the circuit.

If the refractory period is shorter than the time it takes the wave to complete the circuit, re-entrant electric conduction may occur.

If the conduction barrier becomes large enough, the conduction wave will meet repolarized tissue and re-entry may occur.

If the conduction wave is slowed down by a damaged section of atrial tissue, re-entry may occur.

Image by Lecturio.

Heart rate Heart rate The number of times the heart ventricles contract per unit of time, usually per minute. Cardiac Physiology:
- Atrial rate > 300/min
- Some beats are irregularly modulated by the atrioventricular (AV) node
- Ventricular rate = 90–170/min
Effects:
- Atrial remodeling: irregular impulses and contractions lead to progressive dilation and fibrosis Fibrosis Any pathological condition where fibrous connective tissue invades any organ, usually as a consequence of inflammation or other injury. Bronchiolitis Obliterans of the atria → higher risk for AF → vicious cycle of pathology
- Asynchronous contractility → atria lose systolic function
- Rapid uncontrolled atrial contractions ( > 300/min) → slower pass through the AV node → uncoordinated ventricular contractions (90–170/min) → 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
- Decreased cardiac output Cardiac output The volume of blood passing through the heart per unit of time. It is usually expressed as liters (volume) per minute so as not to be confused with stroke volume (volume per beat). Cardiac Mechanics → stasis of blood → promotes thromboembolism Thromboembolism Obstruction of a blood vessel (embolism) by a blood clot (thrombus) in the blood stream. Systemic Lupus Erythematosus
- Decreased cardiac output Cardiac output The volume of blood passing through the heart per unit of time. It is usually expressed as liters (volume) per minute so as not to be confused with stroke volume (volume per beat). Cardiac Mechanics → 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)

Classification

Paroxysmal: AF that starts spontaneously and terminates spontaneously or with intervention within 7 days of onset; episodes may occur with variable Variable Variables represent information about something that can change. The design of the measurement scales, or of the methods for obtaining information, will determine the data gathered and the characteristics of that data. As a result, a variable can be qualitative or quantitative, and may be further classified into subgroups. Types of Variables frequency
Persistent: AF that fails to self-terminate within 7 days, requires pharmacologic or electrical cardioversion to terminate
Long-standing persistent: AF that has lasted for more than 12 months
Permanent: AF that is unresponsive to treatment, patient and doctor decide to no longer pursue a rhythm control strategy
Lone: Obsolete term; use of term is controversial and discouraged
- paroxysmal, persistent, or permanent AF with no structural heart disease, typically in persons < 60 years old, the lowest risk of complications → patients have a CHA₂DS₂-VASc score of “0”
Secondary: due to underlying condition, treatment focuses on the underlying condition to resolve AF
Subclinical: AF in asymptomatic individuals without a prior diagnosis of AF, often found in the context of implantable cardiac monitoring devices

Clinical Presentation

AF is often asymptomatic.
If patients Patients Individuals participating in the health care system for the purpose of receiving therapeutic, diagnostic, or preventive procedures. Clinician–Patient Relationship experience symptoms, these are often nonspecific and variable Variable Variables represent information about something that can change. The design of the measurement scales, or of the methods for obtaining information, will determine the data gathered and the characteristics of that data. As a result, a variable can be qualitative or quantitative, and may be further classified into subgroups. Types of Variables.
- Palpitations Palpitations Ebstein’s Anomaly
- 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
- Chest pain Pain An unpleasant sensation induced by noxious stimuli which are detected by nerve endings of nociceptive neurons. Pain: Types and Pathways
- Fatigue Fatigue The state of weariness following a period of exertion, mental or physical, characterized by a decreased capacity for work and reduced efficiency to respond to stimuli. Fibromyalgia
- 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
- 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
- Confusion
- Mild 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
- Embolic event
If symptoms are atypical → notice signs of the underlying disorder (e.g., exophthalmos in hyperthyroidism Hyperthyroidism Hypersecretion of thyroid hormones from the thyroid gland. Elevated levels of thyroid hormones increase basal metabolic rate. Thyrotoxicosis and Hyperthyroidism, murmur in the case of a valvular defect)
Complications of long-standing AF:
- Signs 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) ( 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, orthopnea Orthopnea Pulmonary Edema, paroxysmal nocturnal dyspnea Paroxysmal nocturnal dyspnea A disorder characterized by sudden attacks of respiratory distress in at rest patients with heart failure and pulmonary edema. It usually occurs at night after several hours of sleep in a reclining position. Patients awaken with a feeling of suffocation, coughing, a cold sweat, and tachycardia. When there is significant wheezing, it is called cardiac asthma. Pulmonary Edema, 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 at rest, pitting edema Pitting edema Edema caused by excess fluid without excess colloid. Leaves “pits” due to fluid displacement when pressure is applied to the area Edema, S3 S3 Heart Sounds, S4 S4 Heart Sounds)
- Signs of 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 (stroke/ transient ischemic attack Transient ischemic attack Transient ischemic attack (TIA) is a temporary episode of neurologic dysfunction caused by ischemia without infarction that resolves completely when blood supply is restored. Transient ischemic attack is a neurologic emergency that warrants urgent medical attention. Transient Ischemic Attack (TIA) [ TIA TIA Transient ischemic attack (TIA) is a temporary episode of neurologic dysfunction caused by ischemia without infarction that resolves completely when blood supply is restored. Transient ischemic attack is a neurologic emergency that warrants urgent medical attention. Transient Ischemic Attack (TIA)] presenting with focal neurologic deficits Neurologic Deficits High-Risk Headaches such as paresis Paresis A general term referring to a mild to moderate degree of muscular weakness, occasionally used as a synonym for paralysis (severe or complete loss of motor function). In the older literature, paresis often referred specifically to paretic neurosyphilis. ‘general paresis’ and ‘general paralysis’ may still carry that connotation. Bilateral lower extremity paresis is referred to as paraparesis. Spinal Disk Herniation, vision Vision Ophthalmic Exam loss, or renal, splenic, or intestinal infarct Infarct Area of necrotic cells in an organ, arising mainly from hypoxia and ischemia Ischemic Cell Damage)

Diagnosis

Electrocardiogram Electrocardiogram 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) ( 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)): confirms diagnosis

Irregularly irregular (pathognomonic)
RR RR Relative risk (RR) is the risk of a disease or condition occurring in a group or population with a particular exposure relative to a control (unexposed) group. Measures of Risk intervals follow no repetitive pattern
No distinct P waves
Narrow QRS complexes (< 0.12 seconds)

Echocardiogram Echocardiogram Transposition of the Great Arteries: used to identify etiology and complications, not for diagnosis

Transthoracic echocardiogram Transthoracic echocardiogram Endocarditis ( TTE TTE Imaging of the Heart and Great Vessels):
- Used to assess cardiac function
- Rules out or confirms structural cardiac disease (e.g., valve stenosis Stenosis Hypoplastic Left Heart Syndrome (HLHS))
Transesophageal echocardiogram Echocardiogram Transposition of the Great Arteries ( TEE TEE Ultrasonic recording of the size, motion, and composition of the heart and surrounding tissues using a transducer placed in the esophagus. Imaging of the Heart and Great Vessels):
- Rules out or confirms the structural cardiac disease
- Indicated if AF lasted for > 48 hrs HRS Hepatorenal syndrome (HRS) is a potentially reversible cause of acute kidney injury that develops secondary to liver disease. The main cause of hrs is hypovolemia, often as a result of forced diuresis or drainage of ascites. This leads to renal vasoconstriction resulting in hypoperfusion of the kidneys. Hepatorenal Syndrome or if the duration is unknown
- Indicated if planning cardioversion on patients Patients Individuals participating in the health care system for the purpose of receiving therapeutic, diagnostic, or preventive procedures. Clinician–Patient Relationship who haven’t received anticoagulation Anticoagulation Pulmonary Hypertension Drugs therapy for at least 3 weeks
- Used to detect thrombi within the left atrium or left atrial appendage

Other tests to rule out underlying conditions:

Cardiac 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 → myocardial infarction Myocardial infarction MI is ischemia and death of an area of myocardial tissue due to insufficient blood flow and oxygenation, usually from thrombus formation on a ruptured atherosclerotic plaque in the epicardial arteries. Clinical presentation is most commonly with chest pain, but women and patients with diabetes may have atypical symptoms. Myocardial Infarction
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 → 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)
TSH/fT4 → hyperthyroidism Hyperthyroidism Hypersecretion of thyroid hormones from the thyroid gland. Elevated levels of thyroid hormones increase basal metabolic rate. Thyrotoxicosis and Hyperthyroidism
CBC → infection/ sepsis Sepsis Systemic inflammatory response syndrome with a proven or suspected infectious etiology. When sepsis is associated with organ dysfunction distant from the site of infection, it is called severe sepsis. When sepsis is accompanied by hypotension despite adequate fluid infusion, it is called septic shock. Sepsis and Septic Shock
BUN, creatinine → kidney function
HbA_1c → 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
D-dimer D-dimer Deep Vein Thrombosis → venous thromboembolism Thromboembolism Obstruction of a blood vessel (embolism) by a blood clot (thrombus) in the blood stream. Systemic Lupus Erythematosus
Electrolytes Electrolytes Electrolytes are mineral salts that dissolve in water and dissociate into charged particles called ions, which can be either be positively (cations) or negatively (anions) charged. Electrolytes are distributed in the extracellular and intracellular compartments in different concentrations. Electrolytes are essential for various basic life-sustaining functions. Electrolytes ( 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, calcium Calcium A basic element found in nearly all tissues. It is a member of the alkaline earth family of metals with the atomic symbol ca, atomic number 20, and atomic weight 40. Calcium is the most abundant mineral in the body and combines with phosphorus to form calcium phosphate in the bones and teeth. It is essential for the normal functioning of nerves and muscles and plays a role in blood coagulation (as factor IV) and in many enzymatic processes. Electrolytes, or 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) → electrolyte imbalances
Urine drug screen → 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, amphetamines Amphetamines Analogs or derivatives of amphetamine. Many are sympathomimetics and central nervous system stimulators causing excitation, vasopressin, bronchodilation, and to varying degrees, anorexia, analepsis, nasal decongestion, and some smooth muscle relaxation. Stimulants, digoxin Digoxin A cardiotonic glycoside obtained mainly from digitalis lanata; it consists of three sugars and the aglycone digoxigenin. Digoxin has positive inotropic and negative chronotropic activity. It is used to control ventricular rate in atrial fibrillation and in the management of congestive heart failure with atrial fibrillation. Its use in congestive heart failure and sinus rhythm is less certain. The margin between toxic and therapeutic doses is small. Cardiac Glycosides, or alcohol
CT pulmonary angiography Angiography Radiography of blood vessels after injection of a contrast medium. Cardiac Surgery → 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
Exercise testing → ischemic heart disease Ischemic 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, also guides pharmacotherapy
Sleep Sleep A readily reversible suspension of sensorimotor interaction with the environment, usually associated with recumbency and immobility. Physiology of Sleep study → obstructive sleep apnea Sleep apnea Repeated cessation of breathing for > 10 seconds during sleep and results in sleep interruption, fatigue, and daytime sleepiness. Obstructive Sleep Apnea
Cardiac catheterization Cardiac Catheterization Procedures in which placement of cardiac catheters is performed for therapeutic or diagnostic procedures. Cardiac Surgery → coronary artery Coronary Artery Truncus Arteriosus disease, 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

Ecg atrial fribrillation — ECG shows an irregularly irregular rhythm of atrial fibrillation in a thyrotoxic patient
Image: “Initial electrocardiogram (ECG) at presentation to the emergency room” by ST4 Diabetes and Endocrinology Princess of Wales Hospital Bridgend, CF31 1RQ UK. License: CC BY 3.0

Rapid ventricular rate — ECG shows an irregularly irregular rhythm of atrial fibrillation in a thyrotoxic patient
Image: “Initial electrocardiogram (ECG) at presentation to the emergency room” by ST4 Diabetes and Endocrinology Princess of Wales Hospital Bridgend, CF31 1RQ UK. License: CC BY 3.0

Management

AF management consists of the following:

Determination of hemodynamic status
Rate control OR rhythm control
Anticoagulation Anticoagulation Pulmonary Hypertension Drugs therapy
Treatment of the underlying cause

Special considerations:

Newly discovered AF < 24–48 hours → electrical cardioversion (can be performed without AC) provided there are no high thromboembolic risk factors (e.g., CHA₂DS₂-VASc ≥ 2 or prior stroke/ TIA TIA Transient ischemic attack (TIA) is a temporary episode of neurologic dysfunction caused by ischemia without infarction that resolves completely when blood supply is restored. Transient ischemic attack is a neurologic emergency that warrants urgent medical attention. Transient Ischemic Attack (TIA))
All patients Patients Individuals participating in the health care system for the purpose of receiving therapeutic, diagnostic, or preventive procedures. Clinician–Patient Relationship should have an assessment of their thromboembolic risk.
When ventricular rate is already controlled and hemodynamic stability is achieved, long term management should be decided (rhythm vs rate control).
Early rhythm control is increasingly considered in patients Patients Individuals participating in the health care system for the purpose of receiving therapeutic, diagnostic, or preventive procedures. Clinician–Patient Relationship with new-onset AF and cardiovascular risk factors.
- Recent guidelines also support early rhythm control in a broader range of patients Patients Individuals participating in the health care system for the purpose of receiving therapeutic, diagnostic, or preventive procedures. Clinician–Patient Relationship → has been shown to improve survival in those > 75 years of age with CV CV Vasculitides risks (e.g., DM DM 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, 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), CAD), if performed within 12 months
- For treatment-naive AF, first-line options include antiarrhythmic drug therapy or catheter ablation.

**Table: AF Management principles**
	Management principles	Treatment options
Hemodynamic status	Hemodynamically unstable AF → immediate cardioversion Hemodynamically stable AF → rate control 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) or calcium Calcium A basic element found in nearly all tissues. It is a member of the alkaline earth family of metals with the atomic symbol ca, atomic number 20, and atomic weight 40. Calcium is the most abundant mineral in the body and combines with phosphorus to form calcium phosphate in the bones and teeth. It is essential for the normal functioning of nerves and muscles and plays a role in blood coagulation (as factor IV) and in many enzymatic processes. Electrolytes channel blockers (CCB)
Rate control vs. rhythm control	Rate control Indication: Elderly patient Long-standing AF without aberrant pathways	1st: 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) or non-dihydropyridine Non-Dihydropyridine Pulmonary Hypertension Drugs CCB ( diltiazem Diltiazem A benzothiazepine derivative with vasodilating action due to its antagonism of the actions of calcium ion on membrane functions. Class 4 Antiarrhythmic Drugs (Calcium Channel Blockers), verapamil Verapamil A calcium channel blocker that is a class IV anti-arrhythmia agent. Pulmonary Hypertension Drugs) 2nd: digoxin Digoxin A cardiotonic glycoside obtained mainly from digitalis lanata; it consists of three sugars and the aglycone digoxigenin. Digoxin has positive inotropic and negative chronotropic activity. It is used to control ventricular rate in atrial fibrillation and in the management of congestive heart failure with atrial fibrillation. Its use in congestive heart failure and sinus rhythm is less certain. The margin between toxic and therapeutic doses is small. Cardiac Glycosides/ amiodarone Amiodarone An antianginal and class III antiarrhythmic drug. It increases the duration of ventricular and atrial muscle action by inhibiting potassium channels and voltage-gated sodium channels. There is a resulting decrease in heart rate and in vascular resistance. Pulmonary Fibrosis (refractory to 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) or CCB or with 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))
Rate control vs. rhythm control	Rhythm control Indication: Recent onset Young patient Symptomatic	Electrical cardioversion (with appropriate anticoagulation Anticoagulation Pulmonary Hypertension Drugs protocol) Pharmacological cardioversion (e.g., flecainide Flecainide A potent anti-arrhythmia agent, effective in a wide range of ventricular and atrial arrhythmias and tachycardias. Class 1 Antiarrhythmic Drugs (Sodium Channel Blockers), propafenone Propafenone An antiarrhythmic agent that is particularly effective in ventricular arrhythmias. It also has weak beta-blocking activity. Class 1 Antiarrhythmic Drugs (Sodium Channel Blockers)) Surgical or catheter ablation
Anticoagulation Anticoagulation Pulmonary Hypertension Drugs	Warfarin Warfarin An anticoagulant that acts by inhibiting the synthesis of vitamin K-dependent coagulation factors. Warfarin is indicated for the prophylaxis and/or treatment of venous thrombosis and its extension, pulmonary embolism, and atrial fibrillation with embolization. It is also used as an adjunct in the prophylaxis of systemic embolism after myocardial infarction. Warfarin is also used as a rodenticide. Anticoagulants, novel oral anticoagulants Anticoagulants Anticoagulants are drugs that retard or interrupt the coagulation cascade. The primary classes of available anticoagulants include heparins, vitamin K-dependent antagonists (e.g., warfarin), direct thrombin inhibitors, and factor Xa inhibitors. Anticoagulants (NOAC)	Indication: Non-valvular AF (CHA₂DS₂-VA ≥ 1) In all valvular causes
	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) (antiplatelet therapy)	Indication: CHA₂DS₂-VA < 1 With coronary artery Coronary Artery Truncus Arteriosus disease
	Cardioversion protocol (electrical or pharmacological)	3 weeks prior and 4 weeks post-cardioversion
Treat underlying cause	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, coronary artery Coronary Artery Truncus Arteriosus disease, valvular heart disease, chronic obstructive pulmonary disease Pulmonary disease Diseases involving the respiratory system. Blastomyces/Blastomycosis, thyrotoxicosis Thyrotoxicosis A hypermetabolic syndrome caused by excess thyroid hormones which may come from endogenous or exogenous sources. The endogenous source of hormone may be thyroid hyperplasia; thyroid neoplasms; or hormone-producing extrathyroidal tissue. Thyrotoxicosis is characterized by nervousness; tachycardia; fatigue; weight loss; heat intolerance; and excessive sweating. Thyrotoxicosis and Hyperthyroidism, sick sinus syndrome Sick Sinus Syndrome Sick sinus syndrome (SSS), also known as sinus node dysfunction, is characterized by degeneration of the sinoatrial (SA) node, the heart’s primary pacemaker. Patients with SSS may be asymptomatic or may present with tachycardia or bradycardia. Sick Sinus Syndrome, etc ETC The electron transport chain (ETC) sends electrons through a series of proteins, which generate an electrochemical proton gradient that produces energy in the form of adenosine triphosphate (ATP). Electron Transport Chain (ETC).

**CHA₂DS₂-VA Score:** assesses thromboembolic risk and the risk for stroke in patients Patients Individuals participating in the health care system for the purpose of receiving therapeutic, diagnostic, or preventive procedures. Clinician–Patient Relationship with AF
C	Congestive 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)	1
H	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	1
A	Age (≥ 75 years)	2
D	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 mellitus	1
S	Stroke, TIA TIA Transient ischemic attack (TIA) is a temporary episode of neurologic dysfunction caused by ischemia without infarction that resolves completely when blood supply is restored. Transient ischemic attack is a neurologic emergency that warrants urgent medical attention. Transient Ischemic Attack (TIA), or thromboembolism Thromboembolism Obstruction of a blood vessel (embolism) by a blood clot (thrombus) in the blood stream. Systemic Lupus Erythematosus	2
V	Vascular disease	1
A	Age 65–74 years	1

Scores of 1, 3, 5, and ≥ 6 carry an annual stroke risk of approximately 1%, 3%, 7%, and > 9%, respectively.

Differential Diagnosis

The following conditions are differential diagnoses for AF:

Atrial flutter Atrial flutter Atrial flutter is a regular supraventricular tachycardia characterized by an atrial heart rate between 240/min and 340/min (typically 300/min), atrioventricular (AV) node conduction block, and a “sawtooth” pattern on an electrocardiogram (ECG). Atrial Flutter: an irregular heart rhythm of the atria. It is classified as supraventricular 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. Symptoms include palpitations Palpitations Ebstein’s Anomaly. Complications include increased risk of stroke and 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).
- Key difference: Flutter is a regular Regular Insulin rhythm whereas fibrillation is irregular.
Paroxysmal supraventricular 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: a type of supraventricular 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 characterized by narrow QRS complexes and a fast heart rhythm, typically between 150 and 240 beats per minute
Multifocal atrial tachycardia Multifocal atrial tachycardia Tachyarrhythmias: a type of atrial arrhythmia characterized by rapid heart rate Heart rate The number of times the heart ventricles contract per unit of time, usually per minute. Cardiac Physiology with at least 3 or more P wave P wave Electrocardiogram (ECG) morphologies. It is called multifocal Multifocal Retinoblastoma since the signals arise from various zones within the atria other than the sinus node.
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 atrial contractions: common ectopic beats generated from foci in atria, triggering 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 heartbeats

References

Holder, S., & Amin, P. (2024). Atrial Fibrillation: Common Questions and Answers About Diagnosis and Treatment. American family physician, 109(5), 398–404.
Nayak, S., Natarajan, B., Pai, R. G. (2020). Etiology, pathology, and classification of atrial fibrillation. International Journal of Angiology, 29(2), 65–71. https://doi.org/10.1055/s-0040-1705153
Joglar, J. A., Chung, M. K., Armbruster, A. L., Benjamin, E. J., Chyou, J. Y., Cronin, E. M., Deswal, A., Eckhardt, L. L., Goldberger, Z. D., Gopinathannair, R., Gorenek, B., Hess, P. L., Hlatky, M., Hogan, G., Ibeh, C., Indik, J. H., Kido, K., Kusumoto, F., Link, M. S., Linta, K. T., … Peer Review Committee Members (2024). 2023 ACC/AHA/ACCP/ HRS HRS Hepatorenal syndrome (HRS) is a potentially reversible cause of acute kidney injury that develops secondary to liver disease. The main cause of hrs is hypovolemia, often as a result of forced diuresis or drainage of ascites. This leads to renal vasoconstriction resulting in hypoperfusion of the kidneys. Hepatorenal Syndrome Guideline for the Diagnosis and Management of Atrial Fibrillation: A Report of the American College of Cardiology/ American Heart Association American Heart Association A voluntary organization concerned with the prevention and treatment of heart and vascular diseases. Heart Failure Joint Committee on Clinical Practice Guidelines. Circulation Circulation The movement of the blood as it is pumped through the cardiovascular system. ABCDE Assessment, 149(1), e1 E1 An aromatized C18 steroid with a 3-hydroxyl group and a 17-ketone, a major mammalian estrogen. It is converted from androstenedione directly, or from testosterone via estradiol. In humans, it is produced primarily by the cyclic ovaries, placenta, and the adipose tissue of men and postmenopausal women. Noncontraceptive Estrogen and Progestins–e156. https://doi.org/10.1161/CIR.0000000000001193
Kumar, K. (2023). Overview and management of new-onset atrial fibrillation. UpToDate. Retrieved May 26, 2025, from https://www.uptodate.com/contents/atrial-fibrillation-overview-and-management-of-new-onset-atrial-fibrillation
Spragg, D., Kumar, K. (2023) Paroxysmal atrial fibrillation. UpToDate. Retrieved May 26, 2025, from https://www.uptodate.com/contents/paroxysmal-atrial-fibrillation
Rosenthal, L. (2025) Atrial fibrillation. Medscape. Retrieved May 26, 2025, from https://emedicine.medscape.com/article/151066-overview#a2
Manning, W. (2024). Role of 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) in atrial fibrillation. UpToDate. Retrieved May 8, 2025, from https://www.uptodate.com/contents/role-of-echocardiography-in-atrial-fibrillation
Pham, H. N., Ibrahim, R., Truong, H. H., Sainbayar, E., Tran, V. N., Abdelnabi, M., Kanaan, C., & Sridharan, A. (2024). Advances in Atrial Fibrillation Management: A Guide for General Internists. Journal of clinical medicine, 13(24), 7846. https://doi.org/10.3390/jcm13247846
Naccarelli, G., Manning, W. (2025) Atrial fibrillation: cardioversion. UpToDate. Retrieved May 26, 2025, from https://www.uptodate.com/contents/atrial-fibrillation-cardioversion
Bonfanti, L., Annovi, A., Sanchis-Gomar, F., Saccenti, C., Meschi, T., Ticinesi, A., Cervellin, G. (2019). Effectiveness and safety of electrical cardioversion for acute-onset atrial fibrillation in the emergency department: a real-world 10-year single center experience. Clinical and Experimental Emergency Medicine, 6(1), 64–69. https://doi.org/10.15441/ceem.17.286
Kumar, K., Manning, W. (2023) Rhythm control vs rate control in atrial fibrillation. UpToDate. Retrieved May 26, 2025, from https://www.uptodate.com/contents/rhythm-control-versus-rate-control-in-atrial-fibrillation
January, C., Wann, L. S., Calkins, H., Chen, L., Cigarroa, J., Cleveland, J., Jr., Ellinor, P., Ezekowitz, M., Field, M., Furie, K., Heidenreich, P., Murray, K., Shea, J., Tracy, C., Yancy, C. (2019). 2019 AHA/ACC/ HRS HRS Hepatorenal syndrome (HRS) is a potentially reversible cause of acute kidney injury that develops secondary to liver disease. The main cause of hrs is hypovolemia, often as a result of forced diuresis or drainage of ascites. This leads to renal vasoconstriction resulting in hypoperfusion of the kidneys. Hepatorenal Syndrome Focused Update of the 2014 AHA/ACC/ HRS HRS Hepatorenal syndrome (HRS) is a potentially reversible cause of acute kidney injury that develops secondary to liver disease. The main cause of hrs is hypovolemia, often as a result of forced diuresis or drainage of ascites. This leads to renal vasoconstriction resulting in hypoperfusion of the kidneys. Hepatorenal Syndrome guideline for the management of patients Patients Individuals participating in the health care system for the purpose of receiving therapeutic, diagnostic, or preventive procedures. Clinician–Patient Relationship with atrial fibrillation: a report of the American College of Cardiology/ American Heart Association American Heart Association A voluntary organization concerned with the prevention and treatment of heart and vascular diseases. Heart Failure Task Force on Clinical Practice Guidelines and the Heart Rhythm Society in collaboration with the Society of Thoracic Surgeons. Circulation Circulation The movement of the blood as it is pumped through the cardiovascular system. ABCDE Assessment,140, e125–e151. https://www.ahajournals.org/doi/10.1161/CIR.0000000000000665#d3e1148
Phang, R., Manning, W. (2023). Prevention of 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 prior to and after restoration of sinus rhythm Sinus rhythm A heart rate and rhythm driven by the regular firing of the SA node (60–100 beats per minute) Cardiac Physiology in atrial fibrillation. UpToDate. Retrieved May 26, 2025 from https://www.uptodate.com/contents/prevention-of-embolization-prior-to-and-after-restoration-of-sinus-rhythm-in-atrial-fibrillation
Kaplan, R. (2023). Control of ventricular rate in atrial fibrillation: pharmacologic therapy. UpToDate. Retrieved May 26, 2025, from https://www.uptodate.com/contents/control-of-ventricular-rate-in-atrial-fibrillation-pharmacologic-therapy
Kumar, K. (2023). Antiarrhythmic drugs to maintain sinus rhythm Sinus rhythm A heart rate and rhythm driven by the regular firing of the SA node (60–100 beats per minute) Cardiac Physiology in patients Patients Individuals participating in the health care system for the purpose of receiving therapeutic, diagnostic, or preventive procedures. Clinician–Patient Relationship with atrial fibrillation: recommendations. UpToDate. Retrieved May 26, 2025, from https://www.uptodate.com/contents/antiarrhythmic-drugs-to-maintain-sinus-rhythm-in-patients-with-atrial-fibrillation-recommendations
Passman, R. (2024) Atrial fibrillation: catheter ablation. UpToDate. Retrieved May 26, 2025 from https://www.uptodate.com/contents/atrial-fibrillation-catheter-ablation
Manning, W., Singer, D., Lip, G. (2024) Atrial fibrillation in adults: use of oral anticoagulants Anticoagulants Anticoagulants are drugs that retard or interrupt the coagulation cascade. The primary classes of available anticoagulants include heparins, vitamin K-dependent antagonists (e.g., warfarin), direct thrombin inhibitors, and factor Xa inhibitors. Anticoagulants. UpToDate. Retrieved May 26, 2025 from https://www.uptodate.com/contents/atrial-fibrillation-in-adults-use-of-oral-anticoagulants
Hijazi, Z., Saw., J. (2025) Atrial fibrillation: left atrial appendage occlusion. UpToDate. Retrieved May 26, 2025, from https://www.uptodate.com/contents/atrial-fibrillation-left-atrial-appendage-occlusion
Tomaselli, G. F., Mahaffey, K. W., Cuker, A., Dobesh, P. P., Doherty, J. U., Eikelboom, J. W., Florido, R., Gluckman, T. J., Hucker, W. J., Mehran, R., Messé, S. R., Perino, A. C., Rodriguez, F., Sarode, R., Siegal, D. M., Wiggins, B. S. (2020). 2020 ACC expert consensus decision pathway on management of bleeding in patients Patients Individuals participating in the health care system for the purpose of receiving therapeutic, diagnostic, or preventive procedures. Clinician–Patient Relationship on oral anticoagulants Anticoagulants Anticoagulants are drugs that retard or interrupt the coagulation cascade. The primary classes of available anticoagulants include heparins, vitamin K-dependent antagonists (e.g., warfarin), direct thrombin inhibitors, and factor Xa inhibitors. Anticoagulants: a report of the American College of Cardiology Solution Set Oversight Committee. Journal of the American College of Cardiology, 76(5), 594–622. https://doi.org/10.1016/j.jacc.2020.04.053
Wolfes, J., Ellermann, C., Frommeyer, G., Eckardt, L. (2022). Evidence-based treatment of atrial fibrillation around the globe: comparison of the latest ESC, AHA/ACC/ HRS HRS Hepatorenal syndrome (HRS) is a potentially reversible cause of acute kidney injury that develops secondary to liver disease. The main cause of hrs is hypovolemia, often as a result of forced diuresis or drainage of ascites. This leads to renal vasoconstriction resulting in hypoperfusion of the kidneys. Hepatorenal Syndrome, and CCS CCS Central cord syndrome (CCS) is a neurological syndrome caused by an injury to the center of the spinal cord, affecting the spinothalamic tracts ((STTs) sensory) and medial aspect of the corticospinal tracts ((CSTs) motor), most often due to trauma in patients with cervical spondylosis. Central Cord Syndrome guidelines on the management of atrial fibrillation. Reviews in Cardiovascular Medicine, 23(2), 56. https://www.imrpress.com/journal/RCM/23/2/10.31083/j.rcm2302056
Manning, W., Singer, D., Lip, G. (2024). Atrial fibrillation in adults: selection Selection Lymphocyte activation by a specific antigen thus triggering clonal expansion of lymphocytes already capable of mounting an immune response to the antigen. B cells: Types and Functions of candidates for anticoagulation Anticoagulation Pulmonary Hypertension Drugs. UpToDate. Retrieved May 26, 2025, from https://www.uptodate.com/contents/atrial-fibrillation-in-adults-selection-of-candidates-for-anticoagulation
Heidenreich, P. A., et al AL Amyloidosis. (2021). 2020 update to the 2016 ACC/AHA clinical performance and quality measures Quality Measures Quality Measurement and Improvement for adults with atrial fibrillation or atrial flutter Atrial flutter Atrial flutter is a regular supraventricular tachycardia characterized by an atrial heart rate between 240/min and 340/min (typically 300/min), atrioventricular (AV) node conduction block, and a “sawtooth” pattern on an electrocardiogram (ECG). Atrial Flutter: a report of the American College of Cardiology/ American Heart Association American Heart Association A voluntary organization concerned with the prevention and treatment of heart and vascular diseases. Heart Failure task force on performance measures. Circulation Circulation The movement of the blood as it is pumped through the cardiovascular system. ABCDE Assessment: Cardiovascular 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 and Outcomes, 14, e000100. https://www.ahajournals.org/doi/10.1161/HCQ.0000000000000100
Otto, C.M., et al AL Amyloidosis. (2020). 2020 ACC/AHA guideline for the management of patients Patients Individuals participating in the health care system for the purpose of receiving therapeutic, diagnostic, or preventive procedures. Clinician–Patient Relationship with valvular heart disease: a report of the American College of Cardiology/ American Heart Association American Heart Association A voluntary organization concerned with the prevention and treatment of heart and vascular diseases. Heart Failure joint committee on clinical practice guidelines. Circulation Circulation The movement of the blood as it is pumped through the cardiovascular system. ABCDE Assessment, 143, e72–e227. https://www.ahajournals.org/doi/10.1161/CIR.0000000000000923
Gopinathannair, R., et al AL Amyloidosis. (2021). Managing atrial fibrillation in patients Patients Individuals participating in the health care system for the purpose of receiving therapeutic, diagnostic, or preventive procedures. Clinician–Patient Relationship with 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) and reduced ejection fraction Ejection fraction Cardiac Cycle: a scientific statement from the American Heart Association American Heart Association A voluntary organization concerned with the prevention and treatment of heart and vascular diseases. Heart Failure. Circulation Circulation The movement of the blood as it is pumped through the cardiovascular system. ABCDE Assessment: Arrhythmia and Electrophysiology, 14. https://www.ahajournals.org/doi/10.1161/HAE.0000000000000078
Andrade J. G. (2023). Ablation as First-line Therapy for Atrial Fibrillation. European cardiology, 18, e46. https://doi.org/10.15420/ecr.2023.04
Ullah, W., Johnson, D., Nair, A. S., Dikdan, S. J., Frankel, E., Humayun, W., Pavri, B. B., & Frisch, D. (2024). Ablation Versus Antiarrhythmic Drugs as First-Line Therapy for Treatment-Naive Atrial Fibrillation: A Systematic Review and Meta-Analysis. The American journal of cardiology, 213, 63–68. https://doi.org/10.1016/j.amjcard.2023.11.052

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