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BASICS

  • VSD: defect in interventricular septum causing left-to-right shunt.
  • Second most common congenital heart defect in infants/children.
  • Can be acquired post-myocardial infarction (MI).
  • Severity depends on size of defect and pulmonary vascular resistance.

EPIDEMIOLOGY

  • Congenital VSD incidence: ~2 per 1,000 live births; 30% of congenital cardiac malformations.
  • No gender predilection.
  • Adult prevalence low (~0.3 per 1,000) due to spontaneous closure.
  • Post-MI VSD occurs in 0.2-3% of MI cases.

ETIOLOGY AND PATHOPHYSIOLOGY

  • Congenital origin predominant; post-MI and iatrogenic causes reported.
  • Multifactorial genetics with autosomal dominant and recessive patterns.
  • Left-to-right shunt causes volume overload to lungs and left heart.
  • Prolonged shunt leads to pulmonary hypertension, potential shunt reversal (Eisenmenger complex).

RISK FACTORS

  • Congenital: family history, prematurity.
  • Post-MI: advanced age, arterial hypertension, anterior MI, first MI, usually within first week post-MI.

GENERAL PREVENTION

  • Avoid prenatal exposures to teratogens (e.g., COX inhibitors, marijuana, organic solvents).
  • Adults: manage MI risk factors and evaluate before pregnancy.

COMMONLY ASSOCIATED CONDITIONS

  • Congenital: Tetralogy of Fallot, Down syndrome, other septal defects, valvular deformities.
  • Adult: coronary artery disease.

DIAGNOSIS

History

  • Depends on shunt size: may be asymptomatic if small.
  • Symptoms: respiratory distress, tachypnea, tachycardia, diaphoresis with feeding, poor weight gain in infants.

Physical Exam

  • Small VSD: harsh holosystolic murmur at left lower sternal border (after PVR drops at 4-8 weeks).
  • Moderate VSD: murmur with thrill, forceful displaced apical impulse, loud P2, diastolic rumble at apex.
  • Large VSD: holosystolic murmur with diastolic rumble, precordial bulge; signs of CHF and pulmonary hypertension.
  • Eisenmenger complex: cyanosis, clubbing, syncope, arrhythmias, polycythemia.

DIFFERENTIAL DIAGNOSIS

  • Patent ductus arteriosus.
  • Atrial septal defect.
  • Tetralogy of Fallot (children).
  • Mitral regurgitation (adults).

DIAGNOSTIC TESTS & INTERPRETATION

  • ECG: LV hypertrophy, LA enlargement; later RV hypertrophy and RA enlargement with pulmonary hypertension.
  • Chest X-ray: increased pulmonary vascular markings, cardiomegaly.
  • Echocardiography with color Doppler: defines location, size, shunt direction.
  • Cardiac catheterization: quantifies shunt, pulmonary vascular resistance, perioperative planning.

TREATMENT

Medical

  • Small VSDs often close spontaneously.
  • Manage CHF signs with diuretics (furosemide, spironolactone), ACE inhibitors (captopril), digoxin.
  • Nutritional support including nasogastric feeding and iron supplementation.
  • Post-MI VSD: stabilize with afterload reduction, inotropes, mechanical support (IABP, LV assist device).

Surgical

  • Indicated for large defects with pulmonary overcirculation or failure to thrive.
  • Early surgery recommended if persistent pulmonary hypertension.
  • Surgical repair involves patch closure; good outcomes with rare complications.
  • Percutaneous device closure is an option for selected small to moderate defects.

ISSUES FOR REFERRAL

  • Close cardiology follow-up until surgical repair.
  • Referral for surgery or interventional cardiology for closure.

ONGOING CARE

  • Frequent follow-up based on defect size and symptoms.
  • Monitor growth, hematocrit.
  • RSV prophylaxis for infants with hemodynamically significant defects.
  • Dietary sodium restriction if CHF present.
  • High-calorie diet for failure to thrive.

PATIENT EDUCATION

  • No activity restriction if no pulmonary hypertension.
  • Educate parents about signs of complications.
  • Importance of follow-up and timely surgery.

PROGNOSIS

  • Small VSD: spontaneous closure common by age 3 years.
  • Large VSD: requires surgery; risk of pulmonary hypertension, Eisenmenger syndrome if untreated.
  • Post-MI VSD: high mortality (80-90%) without surgery.
  • Long-term survival excellent after repair (20-year survival ~87%).

COMPLICATIONS

  • Congestive heart failure.
  • Aortic insufficiency.
  • Sudden death.
  • Hemoptysis.
  • Cerebral abscess.
  • Paradoxical embolism.
  • Cardiogenic shock.
  • Postoperative heart block.

REFERENCES

  1. Scully BB, Morales DLS, Zafar F, et al. Current expectations for surgical repair of isolated ventricular septal defects. Ann Thorac Surg. 2010;89(2):544-549.
  2. Yang L, Tai B-C, Khin LW, et al. A systematic review on the efficacy and safety of closure of ventricular septal defects (VSD). J Interv Cardiol. 2014;27(3):260-272.
  3. Yin S, Zhu D, Lin K, et al. Perventricular device closure of congenital ventricular septal defects. J Card Surg. 2014;29(3):390-400.
  4. Penny DJ, Vick GW III. Ventricular septal defect. Lancet. 2011;377(9771):1103-1112.

ICD10

  • Q21.0 Ventricular septal defect
  • I23.2 Ventricular septal defect as current complication following AMI
  • Q21.3 Tetralogy of Fallot

Clinical Pearls

  • Typical murmur: low-pitched, harsh holosystolic murmur at left lower sternal border (2/6 to 3/6 intensity).
  • Diastolic rumble at apex indicates moderate to large shunt.
  • Murmur may disappear with development of pulmonary hypertension or spontaneous closure.
  • Early diagnosis and treatment essential to prevent irreversible pulmonary vascular disease.