What is the most common congenital cardiac defect?

The Most Common Congenital Cardiac Defect

The most common congenital cardiac defect is ventricular septal defect (VSD), which corresponds to option (b). 1, 2, 3

Epidemiology of VSDs

• Ventricular septal defects occur in approximately 3.0 to 3.5 infants per 1000 live births, making them the most prevalent congenital heart defect at birth 1
• VSDs account for approximately 37% of all congenital heart disease in children 3
• Recent population-based data from the Copenhagen Baby Heart Study found a prevalence of 3.3% in newborns, which decreases to 0.5% by one year of age due to spontaneous closure 4
• VSDs are more frequent than atrial septal defects, transposition of the great arteries, tetralogy of Fallot, and aortic coarctation 1

Types of VSDs

• VSDs are classified into four anatomic types 1:
  • Type 1 (Subarterial/Outlet): Located in the outflow portion of the right ventricle, accounting for approximately 6% of defects in non-Asian populations and up to 33% in Asian patients 1
  • Type 2 (Perimembranous): The most common type, representing approximately 80% of all VSDs 1
  • Type 3 (Inlet): Commonly associated with Down syndrome 1
  • Type 4 (Muscular): Often multiple and have a high rate of spontaneous closure 1

Natural History and Clinical Significance

• The majority of VSDs (83.5%) close spontaneously within the first year of life 4
• Muscular VSDs show significantly higher rates of spontaneous closure (86.9%) compared to perimembranous VSDs (46.9%) 4
• Factors associated with spontaneous closure include smaller size of the VSD and the absence of multiple VSDs 4
• VSDs that don't close spontaneously may require surgical or transcatheter-based intervention depending on their size and hemodynamic significance 3

Comparison with Other Common Congenital Heart Defects

• While ventricular septal defects are the most common, other significant congenital heart defects include:
  • Atrial septal defects (option a): Less common than VSDs 1
  • Transposition of great vessels (option c): The second most common cyanotic congenital cardiac defect, affecting approximately 4.7 in 10,000 live births 5
  • Aortic coarctation (option d): Less common than VSDs 1

Diagnostic Considerations

• Echocardiography with Doppler and color flow mapping is the primary diagnostic tool for VSDs, providing accurate anatomic and hemodynamic evaluation 3
• MRI can be valuable in detecting VSDs that are difficult to visualize with other imaging modalities, particularly in complex cases 6