Clinical features of ventricular septal defect

The patient may be asymptomatic with a small shunt. Large shunts may cause:

• dyspnoea
• recurrent chest infections
• in infancy, failure to thrive, depending on the size of the defect.

On examination there may be:

• bulging sternum - enlarged right ventricle
• cyanosis - if pulmonary vascular resistance is intermittently reversing the direction of the shunt.
• pulse and jugular venous pressure are normal.
• praecordial impulse - if there is a significant shunt then there may be a left parasternal heave and a forceful apical impulse - biventricular hypertrophy.
• rarely there may be a groove in the ribs corresponding to the insertion of the diaphragm, if the lungs have been chronically stiff because of pulmonary plethora.

Auscultation:

• Heart sounds - the loudness of P2 is an indicator of pulmonary vascular resistance. If there is an increase in pulmonary resistance then the pulmonary diastolic pressure increases and P2 becomes louder.
• Murmur of the defect:
  • a very small defect may close in late systole so that the murmur is only heard during early systole.
  • pansystolic murmur and thrill, maximal at the lower left sternal edge in a moderate or large defect
  • if a large defect is not surgically rectified then there is a gradual increase in pulmonary vascular resistance and the murmur diminishes.
• flow murmurs mid-diastolic, through the mitral valve, but usually hidden by the pansystolic murmur
• aortic incompetence may develop in a small percentage of sub-arterial VSDs.