A 6-month-old with known large ventricular septal defect presents with increasing respiratory distress, failure to thrive, and frequent lower respiratory tract infections. On examination, there is a pansystolic murmur at the lower left sternal border, with a mid-diastolic rumble at the apex, and a hepatomegaly. The murmur intensity has recently decreased. What does the decreasing murmur intensity suggest in this context?

• A Spontaneous closure of the VSD
• B Development of Eisenmenger syndrome with reversed shunt
• C Right ventricular outflow tract obstruction developing
• D Increasing pulmonary hypertension equalizing ventricular pressures ✓

Explanation

In a large, unrepaired VSD, increasing pulmonary vascular resistance (pulmonary hypertension) progressively equalizes the pressure difference between the left and right ventricles. As the gradient across the VSD diminishes, the shunt volume decreases and the pansystolic murmur becomes softer or disappears — giving a false impression of 'improvement.' This actually heralds progressive Eisenmenger physiology. The mid-diastolic rumble from high-flow mitral valve is also lost as the shunt reverses. Once right-to-left shunting predominates (Eisenmenger syndrome), surgical repair is contraindicated. This child with congestive heart failure and decreasing murmur should be urgently evaluated for surgical repair before irreversible pulmonary vascular disease develops.

Reference: Ghai Essential Pediatrics, 10th ed.

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

Written and medically reviewed by the StethoPrep medical team.