What are the different types of congenital heart disease (CHD)?

Types of Congenital Heart Disease

Congenital heart disease is classified into three anatomic complexity categories—simple, moderate, and great complexity—based on the 2018 AHA/ACC guidelines, which stratify lesions according to their impact on prognosis, management requirements, and quality of life. 1

Classification Framework

The most clinically useful approach divides CHD by anatomic complexity rather than simply acyanotic versus cyanotic, as this better predicts long-term outcomes and guides management intensity. 1, 2

Type I: Simple CHD

Simple lesions typically require minimal intervention and have excellent prognosis. 2

Native disease includes: 1

• Isolated small atrial septal defect (ASD)
• Isolated small ventricular septal defect (VSD)
• Mild isolated pulmonic stenosis

Repaired conditions include: 1

• Previously ligated or occluded ductus arteriosus
• Repaired secundum ASD without significant residual shunt or chamber enlargement
• Repaired VSD without significant residual shunt or chamber enlargement

Type II: Moderate Complexity CHD

This category encompasses the broadest spectrum of lesions requiring ongoing surveillance and often intervention. 2

Key lesions include: 1

• Atrioventricular septal defect (AVSD), partial or complete
• Coarctation of the aorta
• Ebstein anomaly (spans mild to severe variations)
• Repaired tetralogy of Fallot
• Anomalous pulmonary venous connection (partial or total)
• Anomalous coronary artery arising from the pulmonary artery
• Congenital aortic or mitral valve disease
• Moderate and large unrepaired secundum ASD
• Moderate and large patent ductus arteriosus
• Moderate or greater pulmonary valve regurgitation or stenosis
• Sinus of Valsalva fistula/aneurysm
• Subvalvar or supravalvar aortic stenosis
• VSD with associated abnormality and/or moderate or greater shunt

Type III: Great Complexity (Complex) CHD

These represent the most challenging lesions requiring specialized multidisciplinary care throughout life. 2

Critical lesions include: 1

• All cyanotic congenital heart defects (unrepaired or palliated)
• Single ventricle physiology (including double inlet left ventricle, tricuspid atresia, hypoplastic left heart)
• Fontan procedure patients
• Transposition of the great arteries (d-TGA or l-TGA/CCTGA)
• Truncus arteriosus
• Pulmonary atresia (all forms)
• Double-outlet ventricle
• Interrupted aortic arch
• Mitral atresia
• Other abnormalities of atrioventricular and ventriculoarterial connection (crisscross heart, isomerism, heterotaxy syndromes, ventricular inversion)

Alternative Classification: Acyanotic vs. Cyanotic

While less prognostically useful, the traditional physiologic classification remains clinically relevant for initial assessment. 3

Most common acyanotic lesions: 3

• Ventricular septal defect (most common at birth, 3.0-3.5 per 1000 live births) 4
• Atrial septal defect
• Atrioventricular canal
• Pulmonary stenosis
• Patent ductus arteriosus
• Aortic stenosis
• Coarctation of the aorta

Most common cyanotic lesions: 3

• Tetralogy of Fallot (most common complex defect with longest surgical history) 4
• Transposition of the great arteries

Critical Clinical Distinctions

VSD is the most common CHD at birth (30-40% of all CHD), but many close spontaneously during childhood. 4 In adults, bicuspid aortic valve becomes the most prevalent congenital anomaly, followed by ASD, as approximately 10% of patients with common CHD survive undetected until adulthood. 4

Perimembranous VSDs represent approximately 80% of all VSDs, making them the most common subtype. 4

Physiologic Staging

The AHA/ACC classification combines anatomic complexity with physiologic stage (A through D) to guide treatment intensity, ranging from asymptomatic patients (Stage A) requiring only surveillance to end-stage patients (Stage D) requiring advanced heart failure therapies or transplantation consideration. 2

Management Implications

Patients with moderate and great complexity CHD require care within specialized ACHD programs that provide integrated services including CHD-specific imaging, interventional catheterization, electrophysiology, and cardiac anesthesiology with CHD experience. 2 Complex CHD patients achieve better outcomes when managed in these multidisciplinary programs rather than general cardiology settings. 2

Common pitfall: Approximately one-third of fetal CHD cases are associated with chromosome anomalies, and two-thirds have additional cardiac or extracardiac malformations, necessitating comprehensive evaluation beyond the cardiac defect alone. 5