Ventricular Septal Defect

Description

• Congenital (usually) or acquired defect in the interventricular septum that allows communication of blood between the left and the right ventricles
• Second most common congenital heart malformation reported in infants and children. It can also occur as a late complication of acute myocardial infarction (MI).
• Severity of the defect is correlated with its size, with large defects being the most severe.
• Blood flow across the defect typically is left to right, depending on defect size and pulmonary vascular resistance (PVR).
• Prolonged left-to-right shunting of blood can lead to pulmonary hypertension (HTN). This may eventually lead to a reversal of flow across the defect and cyanosis (Eisenmenger complex)

Geriatric Considerations
Almost entirely associated with late complication of MI

Pediatric Considerations
Congenital defect

Epidemiology

Incidence

• Congenital defect: no gender predilection, occurs in ~2/1,000 live births and accounts for 30% of all congenital cardiac malformations
• Post-MI: Some studies suggest that gender may play a role.

Prevalence
In the United States:

• Occurs in ~50% of all children with congenital heart disease
• Low prevalence in adults (~0.3 per 1,000) due to spontaneous closure
• Post-MI complication in ~0.2–3% of cases

Etiology and Pathophysiology

• Congenital
• In adults, late complication of MI
• Some reports of iatrogenic causes

Genetics
Multifactorial etiology; autosomal dominant and recessive transmissions have been reported.

Risk Factors

• Congenital VSD:
  • Risk of sibling being affected: 4.2%
  • Risk of offspring being affected: 4%
  • Prematurity
• Post-MI VSD:
  • Advanced age
  • Arterial HTN
  • First MI
  • Most frequent within 1st week after MI
  • Most commonly after anterior wall acute MI

General Prevention

Avoid prenatal exposure to known risk factors (ibuprofen cyclooxygenase [COX] inhibitors, marijuana, organic solvents, febrile illness). For adults, avoid risk factors for MI and obtain evaluation before pregnancy.

Commonly Associated Conditions

• Congenital:
  • Tetralogy of Fallot
  • Aortic valvular deformities, especially aortic insufficiency and bicuspid aortic valve
  • Down syndrome (trisomy 21), endocardial cushion defect
  • Transposition of great arteries
  • Coarctation of aorta
  • Tricuspid atresia
  • Truncus arteriosus
  • Patent ductus arteriosus
  • Atrial septal defect
  • Pulmonic stenosis
  • Subaortic stenosis
• Adult: coronary artery disease