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Key Features

Essentials of Diagnosis

  • Holosystolic murmur at lower left sternal border with right ventricular (RV) heave

  • Presentation and course depend on size of defect and the pulmonary vascular resistance (PVR)

  • Failure to thrive, tachypnea, and diaphoresis with eating

  • Left-to-right shunt with normal PVR

  • Large defects may cause Eisenmenger syndrome if not repaired early

General Considerations

  • Accounts for about 30% of all congenital heart disease

  • Defects in the ventricular septum occur both in the membranous portion of the septum (most common) and the muscular portion.

  • VSDs follow one of four courses

    • Small, hemodynamically insignificant VSDs (< 3 mm in diameter)

      • Between 80% and 85% of VSDs are small at birth and will close spontaneously

      • In general, small defects in the muscular interventricular septum close sooner than those in the membranous septum

      • In most cases, a small VSD never requires surgical closure

      • Fifty percent of small VSDs will close by age 2 years, and 90% by age 6 years, with most of the remaining closing during the school years

    • Moderate VSDs (3–5 mm in diameter)

      • Asymptomatic patients with moderate-sized VSDs account for 3–5% of children with VSDs

      • If the patient is asymptomatic and without evidence of pulmonary hypertension, these defects can be monitored serially as some close spontaneously over time

    • Large VSDs with normal PVR (usually 6–10 mm in diameter)

      • Often require surgery; timing depends on the clinical situation

      • Surgery before age 2 years in patients with large VSDs essentially eliminates the risk of pulmonary vascular disease

    • Large VSDs with pulmonary vascular obstructive disease

      • Most patients with inoperable pulmonary hypertension the condition develops progressively

      • The combined data of the multicenter National History Study indicate that almost all cases of irreversible pulmonary hypertension can be prevented by surgical repair of a large VSD before age 2 years

Clinical Findings

  • Patients with small or moderate left-to-right shunts usually have no cardiovascular symptoms

  • Patients with large left-to-right shunts are usually ill early in infancy

  • These infants have frequent respiratory infections and gain weight slowly

  • Dyspnea, diaphoresis, and fatigue can develop as early as 1–6 months of age

  • Older children may experience exercise intolerance

  • In children and adolescents with persistent large left-to-right shunt, the pulmonary vascular bed undergoes structural changes, leading to increased PVR and reversal of the shunt from left-to-right to right-to-left (Eisenmenger syndrome)

  • Cyanosis will then be present

Small left-to-right shunt

  • No lifts, heaves, or thrills

  • The first sound at the apex is normal, and the second sound at the pulmonary area is split physiologically

  • A grade II–IV/VI, medium- to high-pitched, harsh pansystolic murmur is heard best at the left sternal border in the third and fourth intercostal spaces

  • Murmur radiates over the entire precordium

  • No diastolic murmurs are heard

Moderate left-to-right shunt

  • Slight prominence of the precordium ...

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