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Hypoplastic Left Heart Syndrome (HLHS)

Hypoplastic left heart syndrome (HLHS) is a congenital Congenital Chorioretinitis heart defect that consists of the underdevelopment, or hypoplasia, of the left side of the heart in various degrees. The most notable feature of HLHS is the reduced size and functionality of the left ventricle (LV). Also, HLHS is associated with stenosis, hypoplasia, or atresia of the vessels or atrioventricular valves on the left side of the heart. A mixture of genetic factors and altered fetal 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 causes HLHS. Hypoplastic left heart syndrome presents once the ductus arteriosus Ductus arteriosus A fetal blood vessel connecting the pulmonary artery with the descending aorta. Patent Ductus Arteriosus (PDA) closes physiologically as tachypnea Tachypnea Increased respiratory rate. Pulmonary Examination, cyanosis Cyanosis A bluish or purplish discoloration of the skin and mucous membranes due to an increase in the amount of deoxygenated hemoglobin in the blood or a structural defect in the hemoglobin molecule. Pulmonary Examination, 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 cardiogenic shock Cardiogenic shock Shock resulting from diminution of cardiac output in heart disease. Types of Shock. Diagnosis can be made pre- or postnatally via echocardiogram Echocardiogram Transposition of the Great Vessels. Once detected, surgical treatment is the 1st-line therapy, done in 3 stages.

Last updated: 13 Sep, 2021

Editorial responsibility: Stanley Oiseth, Lindsay Jones, Evelin Maza

Overview

Definition

Hypoplastic left heart syndrome (HLHS) is characterized by the underdevelopment of the left side of the heart. The components of HLHS include:

  • Left ventricle (LV) with moderate hypoplasia, non-functional hypoplasia, or complete atresia
  • Mitral valve Mitral valve The valve between the left atrium and left ventricle of the heart. Heart: Anatomy (MV) with stenosis or atresia
  • Aortic valve Aortic valve The valve between the left ventricle and the ascending aorta which prevents backflow into the left ventricle. Heart: Anatomy (AoV) with stenosis or atresia
  • Ascending aorta Ascending aorta Mediastinum and Great Vessels: Anatomy (Ao) with hypoplasia
  • Atrial septal defect Atrial Septal Defect Atrial septal defects (ASDs) are benign acyanotic congenital heart defects characterized by an opening in the interatrial septum that causes blood to flow from the left atrium (LA) to the right atrium (RA) (left-to-right shunt). Atrial Septal Defect (ASD) ( ASD ASD Autism spectrum disorder (ASD) is a neurodevelopmental disorder marked by poor social skills, restricted interests/social interactions, and repetitive/stereotyped behaviors. The condition is termed a “spectrum” because of the wide variability in the severity of symptoms exhibited. Autism Spectrum Disorder) and patent foramen ovale Patent Foramen Ovale A patent foramen ovale (PFO) is an abnormal communication between the atria that persists after birth. The condition results from incomplete closure of the foramen ovale. Small, isolated, and asymptomatic PFOs are a common incidental finding on echocardiography and require no treatment. Patent Foramen Ovale ( PFO PFO A patent foramen ovale (PFO) is an abnormal communication between the atria that persists after birth. The condition results from incomplete closure of the foramen ovale. Small, isolated, and asymptomatic pfos are a common incidental finding on echocardiography and require no treatment. Patent Foramen Ovale)
Hypoplastic left heart syndrome

Hypoplastic left heart syndrome (HLHS) featuring the direction of 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 (arrows) and the oxygenation of blood:
Red represents oxygenated blood, blue shows deoxygenated blood, and purple shows mixed blood.
RA: right atrium
RV: right ventricle
LA: left atrium
LV: left ventricle
SVC: superior vena cava Superior vena cava The venous trunk which returns blood from the head, neck, upper extremities and chest. Mediastinum and Great Vessels: Anatomy
IVC IVC The venous trunk which receives blood from the lower extremities and from the pelvic and abdominal organs. Mediastinum and Great Vessels: Anatomy: inferior vena cava Inferior vena cava The venous trunk which receives blood from the lower extremities and from the pelvic and abdominal organs. Mediastinum and Great Vessels: Anatomy
MPA MPA A primary systemic vasculitis of small- and some medium-sized vessels. It is characterized by a tropism for kidneys and lungs, positive association with anti-neutrophil cytoplasmic antibodies (ANCA), and a paucity of immunoglobulin deposits in vessel walls. Vasculitides: main pulmonary artery Pulmonary artery The short wide vessel arising from the conus arteriosus of the right ventricle and conveying unaerated blood to the lungs. Lungs: Anatomy
Ao: aorta Aorta The main trunk of the systemic arteries. Mediastinum and Great Vessels: Anatomy
PDA PDA The ductus arteriosus (DA) allows blood to bypass pulmonary circulation. After birth, the DA remains open for up to 72 hours and then constricts and involutes, becoming the ligamentum arteriosum. Failure of this process to occur results in patent ductus arteriosus (PDA), a condition that causes up to 10% of congenital heart defects. Patent Ductus Arteriosus (PDA): patent ductus arteriosus Patent ductus arteriosus The ductus arteriosus (DA) allows blood to bypass pulmonary circulation. After birth, the DA remains open for up to 72 hours and then constricts and involutes, becoming the ligamentum arteriosum. Failure of this process to occur results in patent ductus arteriosus (PDA), a condition that causes up to 10% of congenital heart defects. Patent Ductus Arteriosus (PDA)
TV: tricuspid valve Tricuspid valve The valve consisting of three cusps situated between the right atrium and right ventricle of the heart. Heart: Anatomy
MV: mitral valve Mitral valve The valve between the left atrium and left ventricle of the heart. Heart: Anatomy
PV PV Polycythemia vera (PV) is a chronic myeloproliferative neoplasm characterized by the overproduction of rbcs. In addition, the wbc and platelet counts are also increased, which differentiate pv from erythrocytosis seen with chronic hypoxia and other chronic conditions. Polycythemia Vera: pulmonary valve Pulmonary valve A valve situated at the entrance to the pulmonary trunk from the right ventricle. Heart: Anatomy
AoV: aortic valve Aortic valve The valve between the left ventricle and the ascending aorta which prevents backflow into the left ventricle. Heart: Anatomy

Image: “Hypoplastic left heart syndrome” by Centers for Disease Control and Prevention. License: CC0, cropped by Lecturio.

Epidemiology

  • 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: 2–3 out of every 10,000 live births 
  • Accounts for 2%–3% of all congenital Congenital Chorioretinitis heart diseases
  • Accounts for 25%–40% of neonatal deaths due to cardiac Cardiac Total Anomalous Pulmonary Venous Return (TAPVR) causes 
  • 1.5:1 male-to-female ratio

Variants

There are 3 types of HLHS based on the morphology of the cardiac Cardiac Total Anomalous Pulmonary Venous Return (TAPVR) valves:

  1. Aortic and mitral atresia (interchangeable with HLHS):
    • The most severe form
    • LV is absent or “slit-like” and has no output.
    • Short ascending Ao
    • Dependent on the persistence of a ductus arteriosus Ductus arteriosus A fetal blood vessel connecting the pulmonary artery with the descending aorta. Patent Ductus Arteriosus (PDA) for any chance of survival
  2. Aortic atresia plus mitral stenosis Mitral stenosis Mitral stenosis (MS) is the narrowing of the mitral valve (MV) orifice, leading to obstructed blood flow from the left atrium (LA) to the left ventricle (LV). Mitral stenosis is most commonly due to rheumatic heart disease. Mitral stenosis leads to impaired LV diastolic filling, increased LA pressure, and LA dilation. Mitral Stenosis:
    • Hypoplastic ascending Ao
    • LV remodeling and hypertrophy Hypertrophy General increase in bulk of a part or organ due to cell enlargement and accumulation of fluids and secretions, not due to tumor formation, nor to an increase in the number of cells (hyperplasia). Cellular Adaptation related to the degree of stenosis
    • Minimal LV output
  3. Aortic and mitral stenosis Mitral stenosis Mitral stenosis (MS) is the narrowing of the mitral valve (MV) orifice, leading to obstructed blood flow from the left atrium (LA) to the left ventricle (LV). Mitral stenosis is most commonly due to rheumatic heart disease. Mitral stenosis leads to impaired LV diastolic filling, increased LA pressure, and LA dilation. Mitral Stenosis:

Etiology

  • There is a component of genetic predisposition as noted in the 2.5%–5% recurrence rate in siblings: associated with poorer morbidity Morbidity The proportion of patients with a particular disease during a given year per given unit of population. Measures of Health Status (severe neurodevelopmental delay) and higher mortality Mortality All deaths reported in a given population. Measures of Health Status.
  • Associated with chromosomal anomalies, such as:
    • Turner syndrome Turner syndrome Turner syndrome is a genetic condition affecting women, in which 1 X chromosome is partly or completely missing. The classic result is the karyotype 45,XO with a female phenotype. Turner syndrome is associated with decreased sex hormone levels and is the most common cause of primary amenorrhea. Turner Syndrome
    • Trisomy Trisomy The possession of a third chromosome of any one type in an otherwise diploid cell. Types of Mutations 13
    • Trisomy Trisomy The possession of a third chromosome of any one type in an otherwise diploid cell. Types of Mutations 18
    • DiGeorge syndrome DiGeorge syndrome DiGeorge syndrome (DGS) is a condition caused by a microdeletion at location q11.2 of chromosome 22 (thus also called 22q11.2 syndrome). There is a defective development of the third and fourth pharyngeal pouches, leading to thymic and parathyroid hypoplasia (causing T-cell immunodeficiency and hypocalcemia, respectively). DiGeorge Syndrome
  • Postulated to be secondary to reduced 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 in utero through stenosed or atretic AoVs, which leads to the underdevelopment of the LV and ascending Ao
  • May also be linked to intrauterine infarction and/or infection

Pathophysiology

Normal cardiac Cardiac Total Anomalous Pulmonary Venous Return (TAPVR) physiology and development

  • Systemic circulation Circulation The movement of the blood as it is pumped through the cardiovascular system. ABCDE Assessment is maintained in utero via the ductus arteriosus Ductus arteriosus A fetal blood vessel connecting the pulmonary artery with the descending aorta. Patent Ductus Arteriosus (PDA) and foramen ovale Foramen ovale An opening in the wall between the right and the left upper chambers (heart atria) of a fetal heart. Oval foramen normally closes soon after birth; when it fails to close the condition is called patent oval foramen. Patent Foramen Ovale:
    • Fetal body → vena cavae → right atrium (RA) →  foramen ovale Foramen ovale An opening in the wall between the right and the left upper chambers (heart atria) of a fetal heart. Oval foramen normally closes soon after birth; when it fails to close the condition is called patent oval foramen. Patent Foramen Ovale → left atrium (LA) → LV → Ao
    • Also, RA → right ventricle (RV) → ductus arteriosus Ductus arteriosus A fetal blood vessel connecting the pulmonary artery with the descending aorta. Patent Ductus Arteriosus (PDA) → Ao 
  • At birth, physiologic changes occur:
    • Ductus arteriosus Ductus arteriosus A fetal blood vessel connecting the pulmonary artery with the descending aorta. Patent Ductus Arteriosus (PDA) closes → cessation of 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 from the RV to the Ao → systemic perfusion is reduced
    • Pulmonary arterial pressure Pulmonary Arterial Pressure Pulmonary Hypertension Drugs decreases → blood begins to 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 from the RV to the pulmonary circulation Circulation The movement of the blood as it is pumped through the cardiovascular system. ABCDE Assessment

In HLHS

  • Survival depends on the patency of the ductus arteriosus Ductus arteriosus A fetal blood vessel connecting the pulmonary artery with the descending aorta. Patent Ductus Arteriosus (PDA) and foramen ovale Foramen ovale An opening in the wall between the right and the left upper chambers (heart atria) of a fetal heart. Oval foramen normally closes soon after birth; when it fails to close the condition is called patent oval foramen. Patent Foramen Ovale or the presence of an ASD ASD Autism spectrum disorder (ASD) is a neurodevelopmental disorder marked by poor social skills, restricted interests/social interactions, and repetitive/stereotyped behaviors. The condition is termed a “spectrum” because of the wide variability in the severity of symptoms exhibited. Autism Spectrum Disorder to maintain the following circuit:
    • Pulmonary circulation Circulation The movement of the blood as it is pumped through the cardiovascular system. ABCDE Assessment → LA  → ASD ASD Autism spectrum disorder (ASD) is a neurodevelopmental disorder marked by poor social skills, restricted interests/social interactions, and repetitive/stereotyped behaviors. The condition is termed a “spectrum” because of the wide variability in the severity of symptoms exhibited. Autism Spectrum Disorder/ PFO PFO A patent foramen ovale (PFO) is an abnormal communication between the atria that persists after birth. The condition results from incomplete closure of the foramen ovale. Small, isolated, and asymptomatic pfos are a common incidental finding on echocardiography and require no treatment. Patent Foramen Ovale → RA (mixing of oxygenated and deoxygenated blood) → RV → PDA PDA The ductus arteriosus (DA) allows blood to bypass pulmonary circulation. After birth, the DA remains open for up to 72 hours and then constricts and involutes, becoming the ligamentum arteriosum. Failure of this process to occur results in patent ductus arteriosus (PDA), a condition that causes up to 10% of congenital heart defects. Patent Ductus Arteriosus (PDA) → systemic circulation Circulation The movement of the blood as it is pumped through the cardiovascular system. ABCDE Assessment
    • The blood that is flowing through the Ao has a mix of deoxygenated and oxygenated blood, resulting in hypoxemia Hypoxemia Neonatal Respiratory Distress Syndrome.
  • An absence of PDA PDA The ductus arteriosus (DA) allows blood to bypass pulmonary circulation. After birth, the DA remains open for up to 72 hours and then constricts and involutes, becoming the ligamentum arteriosum. Failure of this process to occur results in patent ductus arteriosus (PDA), a condition that causes up to 10% of congenital heart defects. Patent Ductus Arteriosus (PDA), PFO PFO A patent foramen ovale (PFO) is an abnormal communication between the atria that persists after birth. The condition results from incomplete closure of the foramen ovale. Small, isolated, and asymptomatic pfos are a common incidental finding on echocardiography and require no treatment. Patent Foramen Ovale, or ASD ASD Autism spectrum disorder (ASD) is a neurodevelopmental disorder marked by poor social skills, restricted interests/social interactions, and repetitive/stereotyped behaviors. The condition is termed a “spectrum” because of the wide variability in the severity of symptoms exhibited. Autism Spectrum Disorder results in severe cyanosis Cyanosis A bluish or purplish discoloration of the skin and mucous membranes due to an increase in the amount of deoxygenated hemoglobin in the blood or a structural defect in the hemoglobin molecule. Pulmonary Examination, acidosis Acidosis A pathologic condition of acid accumulation or depletion of base in the body. The two main types are respiratory acidosis and metabolic acidosis, due to metabolic acid build up. Respiratory Acidosis, cardiogenic failure, and 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 after delivery. 
  • Progressive, severe hypoxemia Hypoxemia Neonatal Respiratory Distress Syndrome and reduced systemic perfusion results 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) and end-organ damage.
Hlhs vs. Normal heart

The components of HLHS vs. a normal heart

Image: “Hypoplastic left heart syndrome” by Mariana Ruiz. License: Public Domain

Clinical Presentation

  • Infants may be symptomatic or asymptomatic at birth depending on the presence and size of an ASD ASD Autism spectrum disorder (ASD) is a neurodevelopmental disorder marked by poor social skills, restricted interests/social interactions, and repetitive/stereotyped behaviors. The condition is termed a “spectrum” because of the wide variability in the severity of symptoms exhibited. Autism Spectrum Disorder and PDA PDA The ductus arteriosus (DA) allows blood to bypass pulmonary circulation. After birth, the DA remains open for up to 72 hours and then constricts and involutes, becoming the ligamentum arteriosum. Failure of this process to occur results in patent ductus arteriosus (PDA), a condition that causes up to 10% of congenital heart defects. Patent Ductus Arteriosus (PDA). Small or intact atrial septa are associated with severe and rapidly progressive symptoms.
  • At birth: pale or gray-tinted 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 (“dusky appearance”)
  • 24–48 hours after birth:
    • The physiologic closure of the ductus arteriosus Ductus arteriosus A fetal blood vessel connecting the pulmonary artery with the descending aorta. Patent Ductus Arteriosus (PDA) results in the development or aggravation of symptoms.
    • Poor feeding
    • Lethargy Lethargy A general state of sluggishness, listless, or uninterested, with being tired, and having difficulty concentrating and doing simple tasks. It may be related to depression or drug addiction. Hyponatremia
    • Signs of respiratory distress ( 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, tachypnea Tachypnea Increased respiratory rate. Pulmonary Examination, nasal flaring)
    • Signs of cardiogenic shock Cardiogenic shock Shock resulting from diminution of cardiac output in heart disease. Types of Shock ( 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, weak peripheral pulses, cyanosis Cyanosis A bluish or purplish discoloration of the skin and mucous membranes due to an increase in the amount of deoxygenated hemoglobin in the blood or a structural defect in the hemoglobin molecule. Pulmonary Examination, cool extremities, metabolic acidosis Metabolic acidosis The renal system is responsible for eliminating the daily load of non-volatile acids, which is approximately 70 millimoles per day. Metabolic acidosis occurs when there is an increase in the levels of new non-volatile acids (e.g., lactic acid), renal loss of HCO3-, or ingestion of toxic alcohols. Metabolic Acidosis, oliguria Oliguria Decreased urine output that is below the normal range. Oliguria can be defined as urine output of less than or equal to 0. 5 or 1 ml/kg/hr depending on the age. Renal Potassium Regulation, or anuria Anuria Absence of urine formation. It is usually associated with complete bilateral ureteral (ureter) obstruction, complete lower urinary tract obstruction, or unilateral ureteral obstruction when a solitary kidney is present. Acute Kidney Injury)
  • Physical exam:
    • Single S2 S2 Heart Sounds (only the pulmonary valve Pulmonary valve A valve situated at the entrance to the pulmonary trunk from the right ventricle. Heart: Anatomy ( PV PV Polycythemia vera (PV) is a chronic myeloproliferative neoplasm characterized by the overproduction of rbcs. In addition, the wbc and platelet counts are also increased, which differentiate pv from erythrocytosis seen with chronic hypoxia and other chronic conditions. Polycythemia Vera) can be heard closing)
    • Hyperactive precordium
    • No murmurs are heard.
    • Hepatomegaly 
    • Dysmorphic features of associated chromosomal anomalies

Diagnosis

  • Most cases are detected during a prenatal anatomic scan.
  • Confirmed by an echocardiogram Echocardiogram Transposition of the Great Vessels showing:
  • Supportive tests include:
    • Pulse oximetry < 95% 
    • 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)): non-specific
      • Hard to distinguish P waves
      • Signs of RV hypertrophy Hypertrophy General increase in bulk of a part or organ due to cell enlargement and accumulation of fluids and secretions, not due to tumor formation, nor to an increase in the number of cells (hyperplasia). Cellular Adaptation
    • 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: non-specific
      • Cardiomegaly Cardiomegaly Enlargement of the heart, usually indicated by a cardiothoracic ratio above 0. 50. Heart enlargement may involve the right, the left, or both heart ventricles or heart atria. Cardiomegaly is a nonspecific symptom seen in patients with chronic systolic heart failure (heart failure) or several forms of cardiomyopathies. Ebstein’s Anomaly
      • Prominent pulmonary vasculature
  • For patients Patients Individuals participating in the health care system for the purpose of receiving therapeutic, diagnostic, or preventive procedures. Clinician–Patient Relationship in cardiogenic shock Cardiogenic shock Shock resulting from diminution of cardiac output in heart disease. Types of Shock, blood work and arterial blood gas Arterial blood gas Respiratory Alkalosis (ABG) are needed to assess acidosis Acidosis A pathologic condition of acid accumulation or depletion of base in the body. The two main types are respiratory acidosis and metabolic acidosis, due to metabolic acid build up. Respiratory Acidosis secondary to lactic acid buildup.
Hypoplastic left heart syndrome - fetal echocardiography

Postnatal 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) (4-chamber view):
Severe hypoplasia of the LV with hypoplasia of the LA are seen.
LA: left atrium
LV: left ventricle
RA: right atrium
RV: right ventricle

Image: “Hypoplastic left heart syndrome” by Director of Pediatric 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), Department of Congenital Congenital Chorioretinitis Heart Disease, Evelina Children’s Hospital, Guy’s and St Thomas’ NHS Foundation Trust Trust Confidence in or reliance on a person or thing. Conflict of Interest, London, UK. License: CC BY 2.0

Management

Emergent management of 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

  • Prostaglandin E1 Prostaglandin E1 Coarctation of the Aorta infusion to keep the ductus arteriosus Ductus arteriosus A fetal blood vessel connecting the pulmonary artery with the descending aorta. Patent Ductus Arteriosus (PDA) patent
  • Inotropes for 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
  • Bicarbonate Bicarbonate Inorganic salts that contain the -HCO3 radical. They are an important factor in determining the ph of the blood and the concentration of bicarbonate ions is regulated by the kidney. Levels in the blood are an index of the alkali reserve or buffering capacity. Electrolytes infusion for metabolic acidosis Metabolic acidosis The renal system is responsible for eliminating the daily load of non-volatile acids, which is approximately 70 millimoles per day. Metabolic acidosis occurs when there is an increase in the levels of new non-volatile acids (e.g., lactic acid), renal loss of HCO3-, or ingestion of toxic alcohols. Metabolic Acidosis
  • Balloon septoplasty to enlarge a small or deficient foramen ovale Foramen ovale An opening in the wall between the right and the left upper chambers (heart atria) of a fetal heart. Oval foramen normally closes soon after birth; when it fails to close the condition is called patent oval foramen. Patent Foramen Ovale

Surgical management

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

  • Left untreated, HLHS is fatal within the 1st few weeks of life.
  • Good tolerance Tolerance Pharmacokinetics and Pharmacodynamics to exercise after surgery
  • Children who complete all 3 stages of surgery have a survival rate of 90% into adulthood.

Clinical Relevance

The following genetic syndromes are associated with the development of HLHS:

  • Turner syndrome Turner syndrome Turner syndrome is a genetic condition affecting women, in which 1 X chromosome is partly or completely missing. The classic result is the karyotype 45,XO with a female phenotype. Turner syndrome is associated with decreased sex hormone levels and is the most common cause of primary amenorrhea. Turner Syndrome: a chromosomal aberration that produces a 45-chromosome karyotype Karyotype The full set of chromosomes presented as a systematized array of metaphase chromosomes from a photomicrograph of a single cell nucleus arranged in pairs in descending order of size and according to the position of the centromere. Congenital Malformations of the Female Reproductive System with an X0 female phenotype Phenotype The complete genetic complement contained in the DNA of a set of chromosomes in a human. The length of the human genome is about 3 billion base pairs. Basic Terms of Genetics. Presents with decreased sex Sex The totality of characteristics of reproductive structure, functions, phenotype, and genotype, differentiating the male from the female organism. Gender Dysphoria hormone levels; primary amenorrhea Amenorrhea Absence of menstruation. Congenital Malformations of the Female Reproductive System; cardiac Cardiac Total Anomalous Pulmonary Venous Return (TAPVR), renal, reproductive, skeletal, and lymphatic anomalies; short stature; webbed neck Neck The part of a human or animal body connecting the head to the rest of the body. Peritonsillar Abscess; broad chest; low posterior hairline; and peripheral edema Peripheral edema Peripheral edema is the swelling of the lower extremities, namely, legs, feet, and ankles. Edema of the hands and feet. 
  • Holt-Oram syndrome: an autosomal dominant Autosomal dominant Autosomal inheritance, both dominant and recessive, refers to the transmission of genes from the 22 autosomal chromosomes. Autosomal dominant diseases are expressed when only 1 copy of the dominant allele is inherited. Autosomal Recessive and Autosomal Dominant Inheritance condition characterized by the concurrence of congenital Congenital Chorioretinitis cardiopathy, and hypoplastic or aplastic radii and thumbs. 
  • Jacobsen syndrome: a genetic syndrome characterized by the deletion of the long 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 of the 11th chromosome Chromosome In a prokaryotic cell or in the nucleus of a eukaryotic cell, a structure consisting of or containing DNA which carries the genetic information essential to the cell. Basic Terms of Genetics. Ventricular septal defect Ventricular Septal Defect Tetralogy of Fallot and left heart obstructive malformations, including HLHS, are the most commonly associated cardiopathies in Jacobsen syndrome.

The following conditions are differential diagnoses of HLHS:

  • Atrioventricular septal defect: a rare congenital Congenital Chorioretinitis heart defect characterized by the abnormal development of the atrial and ventricular septa and valves. Infants usually present with cyanosis Cyanosis A bluish or purplish discoloration of the skin and mucous membranes due to an increase in the amount of deoxygenated hemoglobin in the blood or a structural defect in the hemoglobin molecule. Pulmonary Examination, 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, 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, tachypnea Tachypnea Increased respiratory rate. Pulmonary Examination, 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 eventually develop 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).
  • ASD ASD Autism spectrum disorder (ASD) is a neurodevelopmental disorder marked by poor social skills, restricted interests/social interactions, and repetitive/stereotyped behaviors. The condition is termed a “spectrum” because of the wide variability in the severity of symptoms exhibited. Autism Spectrum Disorder: a common congenital Congenital Chorioretinitis heart defect characterized by the presence of an opening between the 2 atria of the heart. Patients Patients Individuals participating in the health care system for the purpose of receiving therapeutic, diagnostic, or preventive procedures. Clinician–Patient Relationship present with 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, increased susceptibility to respiratory infections Infections Invasion of the host organism by microorganisms or their toxins or by parasites that can cause pathological conditions or diseases. Chronic Granulomatous Disease, cyanosis Cyanosis A bluish or purplish discoloration of the skin and mucous membranes due to an increase in the amount of deoxygenated hemoglobin in the blood or a structural defect in the hemoglobin molecule. Pulmonary Examination, and embolism, but the appearance and severity of symptoms will depend on the size of the defect.
  • Ventricular septal defect Ventricular Septal Defect Tetralogy of Fallot (VSD): a common congenital Congenital Chorioretinitis heart defect characterized by abnormal communication Communication The exchange or transmission of ideas, attitudes, or beliefs between individuals or groups. Decision-making Capacity and Legal Competence between the LV and RV that results in the left-to-right shunting of 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. Presents as an holosystolic murmur Holosystolic Murmur Tricuspid Valve Atresia (TVA), with progressive 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) and cardiogenic shock Cardiogenic shock Shock resulting from diminution of cardiac output in heart disease. Types of Shock
  • MV stenosis: a rare heart defect characterized by the reduced size of the valve communicating the LA and LV. Symptoms vary greatly depending on the size of the valve and whether the malformation is congenital Congenital Chorioretinitis or acquired. Presents as coughing, 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, palpitations Palpitations Ebstein’s Anomaly, frequent respiratory infections Infections Invasion of the host organism by microorganisms or their toxins or by parasites that can cause pathological conditions or diseases. Chronic Granulomatous Disease, weakness, and 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.

References

  1. Bardo, D. M. E., Frankel, D. G., Applegate, K. E., Murphy, D. J., & Saneto, R. P. (2001). Hypoplastic left heart syndrome. RadioGraphics, 21(3), 705-717. DOI:10.1148/radiographics.21.3.g01ma09705
  2. Kliegman, R. M., M.D., St Geme, Joseph W., MD, Blum, N. J., M.D., Shah, Samir S., M.D., M.S.C.E., Tasker, Robert C., M.B.B.S., M.D., & Wilson, Karen M., M.D., M.P.H. (2020). Cyanotic congenital heart disease: Lesions associated with decreased pulmonary blood flow. In R. M. Kliegman MD, J. W. St Geme MD, N. J. Blum MD, Shah, Samir S., MD, MSCE, Tasker, Robert C., MBBS, MD & Wilson, Karen M., MD, MPH (Eds.), Nelson textbook of pediatrics (pp. 239-2407.e1). https://www.clinicalkey.es/#!/content/3-s2.0-B9780323529501004570
  3. Ohye, R. G., Sleeper, L. A., Mahony, L., Newburger, J. W., Pearson, G. D., Lu, M., . . . Gaynor, J. W. (2010). Comparison of shunt types in the Norwood procedure for single-ventricle lesions. N Engl J Med, 362(21), 1980-1992. DOI:10.1056/NEJMoa0912461
  4. Lara, D. A., Ethen, M. K., Canfield, M. A., Nembhard, W. N., & Morris, S. A. (2017). A population-based analysis of mortality in patients with Turner syndrome and hypoplastic left heart syndrome using the Texas Birth Defects Registry. Congenital heart disease, 12(1), 105–112.
  5. Glauser, T. A., Zackai, E., Weinberg, P., & Clancy, R. (1989). Holt-Oram syndrome associated with the hypoplastic left heart syndrome. Clinical genetics, 36(1), 69–72. DOI:10.1111/j.1399-0004.1989.tb03369.x
  6. Mattina, T., Perrotta, C. S., & Grossfeld, P. (2009). Jacobsen syndrome. Orphanet journal of rare diseases, 4, 9. DOI:10.1186/1750-1172-4-9
  7. Mäkikallio, K., McElhinney, D. B., Levine, J. C., Marx, G. R., Colan, S. D., Marshall, A. C., Lock, J. E., Marcus, E. N., & Tworetzky, W. (2006). Fetal aortic valve stenosis and the evolution of hypoplastic left heart syndrome: patient selection for fetal intervention. Circulation, 113(11), 1401–1405. https://doi.org/10.1161/CIRCULATIONAHA.105.588194

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