Congenital heart disease: an overview
Congenital heart disease (CHD) is a structural cardiac malformation present at birth, classified as acyanotic (left-to-right shunt or obstruction) or cyanotic (right-to-left shunt). Diagnosis is established by echocardiography, and ductal-dependent lesions are stabilized with intravenous alprostadil before lesion-specific surgical or catheter-based repair.
- Topic reviewThe full article, organized the way the exam asks it.
- ABIM-format MCQsVignettes with an explanation for every wrong answer.
- Key factsThe numbers and thresholds worth memorizing, up front.
- AI tutorMedBrain answers the question you're stuck on.
What this article covers
- Overview
Definition: congenital heart disease (CHD) is a structural malformation of the heart or great vessels present at birth, from abnormal cardiac septation, looping, or outflow-tract development.
- Epidemiology
Frequency: CHD affects roughly 8 per 1,000 live births, the most common category of major birth defect.
- Risk factors
Maternal illness and infection: pregestational diabetes (VSD, TGA), phenylketonuria, and congenital rubella (PDA, pulmonary stenosis) each raise CHD risk.
- Pathophysiology
Left-to-right shunts: in VSD, ASD, and PDA, higher left-sided pressure drives oxygenated blood back into the pulmonary circulation; the infant is acyanotic but overcirculates the lungs.
- Clinical features
Small acyanotic shunts: asymptomatic, incidental murmur; VSD gives a harsh holosystolic murmur at the lower left sternal border, ASD a fixed, widely split second heart sound (S2), PDA a continuous "machinery" murmur.
- Differential diagnosis
Persistent pulmonary hypertension of the newborn: cyanosis unresponsive to oxygen, similar to cyanotic CHD, but echocardiography shows a structurally normal heart with elevated pulmonary pressures rather than a shunt.
- Diagnosis
What establishes the diagnosis: bedside vitals and a complete blood count accompany transthoracic echocardiography (TTE) with color Doppler, which establishes the diagnosis by defining shunt…
- Management
First, stabilize and determine ductal dependency: in a cyanotic or shocked neonate with absent femoral pulses or a suspected ductal-dependent lesion, start alprostadil (prostaglandin E1) 0.05-0.1…
- Complications
Eisenmenger syndrome: long-standing, uncorrected shunting causes fixed pulmonary hypertension and shunt reversal, with erythrocytosis, clubbing, and central cyanosis.
- Prognosis
Spontaneous resolution: roughly half of VSDs close by 6 months and most secundum ASDs close by around 4 years.
- Prevention
Preconception counseling: optimize glycemic control in pregestational diabetes, confirm rubella immunity, and avoid teratogens (alcohol, lithium, phenytoin, retinoic acid derivatives).
Read the whole article
Subscribing to Internal Medicine opens every article, the full question bank and MedBrain, on the web, iPhone and Android.
Related articles
- Atrial septal defect
Atrial septal defect is a communication in the interatrial septum causing a left-to-right shunt, often silent until adulthood. It classically produces a fixed split second heart sound and, over time, right heart volume overload, atrial arrhythmias, and pulmonary hypertension; hemodynamically significant defects are closed by device or surgery.
- Ventricular septal defect
Ventricular septal defect is a hole in the interventricular septum causing a left-to-right shunt, the most common congenital heart defect. Small defects produce a loud murmur but close spontaneously, while large defects cause heart failure and pulmonary hypertension and require closure before irreversible pulmonary vascular disease (Eisenmenger physiology) develops.
- Patent ductus arteriosus
Patent ductus arteriosus is persistence of the fetal ductus connecting the aorta and pulmonary artery, causing a continuous machinery murmur and a left-to-right shunt. In preterm infants it is treated with prostaglandin inhibitors; in others it is closed by transcatheter device or surgery, before pulmonary vascular disease develops.
- Coarctation of the aorta
Coarctation of the aorta is a congenital narrowing of the aorta, usually just distal to the left subclavian artery, causing upper-limb hypertension with reduced, delayed lower-limb pulses. Critical neonatal coarctation is duct-dependent, while older children and adults present with hypertension; treatment is surgical or catheter-based repair.
- Eisenmenger syndrome
Eisenmenger syndrome is the end stage of a large uncorrected left-to-right cardiac shunt, in which chronic pulmonary overcirculation causes irreversible pulmonary vascular disease and shunt reversal to right-to-left with cyanosis. The defect can no longer be closed; management is specialized supportive care, pulmonary vasodilators, and avoidance of destabilizing insults.
- Infective endocarditis
Infective endocarditis is microbial infection of the endocardium, usually a heart valve, producing vegetations that cause valve destruction, embolism, and systemic infection. Diagnosis uses the modified Duke criteria combining blood cultures and echocardiography, and treatment is prolonged targeted intravenous antibiotics with surgery for complications.