Ventricular septal defects are L → R shunt lesions, with symptoms depending on the size of the shunt. Small defects are usually asymptomatic, large or long-standing shunts can cause heart failure, pulmonary hypertension and shunt reversal (Eisenmenger’s syndrome, resulting in a R → L shunt with cyanosis). As with all L → R shunts, a decrease in pulmonary vascular resistance should be avoided with air and mild hypoventilation. An increase in systemic vascular resistance should be avoided as well. Inotropes might be needed in heart failure.