This study evaluates the efficacy and safety of sildenafil in patients with Eisenmenger's syndrome with special emphasis on haemodynamic parameters and its comparative efficacy in atrial septal defect versus ventricular septal defect patients.

Oral sildenafil was given to 22 patients with Eisenmenger's syndrome – eight with atrial septal defect and 14 with ventricular septal defect – after detailed baseline evaluation including a six-minute walk test, echocardiography, and cardiac catheterisation. Patients were followed up for a period of 6 months for functional class assessment and six-minute walk distance. Cardiac catheterisation was repeated in all patients.

A significant improvement in the World Health Organization functional class, six-minute walk distance, mean pulmonary arterial pressure, and pulmonary vascular resistance was noticed. Systemic arterial and mixed venous oxygen saturations were also significantly improved along with improvement in pulmonary blood flow. None showed any significant side effects or worsening of systemic arterial saturation. At baseline, mean pulmonary arterial pressure, pulmonary vascular resistance, and pulmonary/systemic vascular resistance ratios were significantly higher in ventricular septal defect patients than in atrial septal defect patients. Atrial septal defect patients showed better response in clinical as well as haemodynamic parameters.

Sildenafil is an effective and safe agent for patients with Eisenmenger's syndrome. It improves their functional capacity as well as haemodynamic parameters. The beneficial effects are greater in patients with Eisenmenger's syndrome secondary to atrial septal defect than ventricular septal defect.