Effects of Viagra on Heart Function in Patients With Heart Failure
Status:
Completed
Trial end date:
2009-11-01
Target enrollment:
Participant gender:
Summary
Sildenafil (Viagra) is known to reduce pulmonary hypertension. Heart failure patients also
have pulmonary hypertension and several recent reports have shown that sildenafil leads to an
improvement in their exercise capacity. In these studies sildenafil caused a reduction in the
pulmonary and systemic vascular resistances, improved pulmonary gas diffusion and perhaps
increased cardiac output. It is uncertain if left ventricular filling pressures are reduced
and whether there is improvement in left ventricular relaxation. The investigators
hypothesize that in heart failure patients the improvement in exercise capacity associated
with sildenafil is related to a significant reduction in left ventricular filling pressures.
The investigators propose to study 20 patients with stable but moderately symptomatic heart
failure. The study design is a randomized cross-over trial of the administration of a single
dose of sildenafil 50 mg or a matching placebo. Exercise capacity will be determined before
and after the oral administration of sildenafil 50 mg or placebo. Left ventricular filling
pressures will be assessed by Doppler echocardiography and the serum level of B-type
natriuretic peptide (BNP is known to increase with higher left ventricular filling
pressures). After an initial echocardiogram and performing a 6 minute walk test, the patient
will then be given either sildenafil or a matching placebo in a randomized double-blind
fashion. One hr later a blood sample for serum BNP, the echocardiogram and the 6 minute walk
test will be repeated.