Sildenafil Effects on Exercise, Neurohormonal Activation, and Erectile Dysfunction in Congestive Heart Failure: A Double-Blind, Placebo-Controlled, Randomized Study Followed by a Prospective Treatment for Erectile Dysfunction

Background—Erectile dysfunction (ED) is common in patients with congestive heart failure (CHF). ED reduces quality of life, and it may affect compliance, thereby impairing the success of CHF treatment. Methods and Results—In the first phase (fixed-dose double-blind, randomized, placebo-controlled, two-way crossover study), we studied in 23 men with CHF the effects of 50 mg sildenafil on exercise and neurohormonal activation. Patients underwent a treadmill 6-minute cardiopulmonary walking (6′WT) test followed by a maximal cardiopulmonary exercise test (ET). In the second phase, patients received sildenafil, taken as required for ED. Sildenafil reduced the heart rate (HR) (bpm) before the 6′WT (from 75±15 to 71±14, P =0.02) and ET (from 75±15 to 71±15, P =0.02); the systolic blood pressure (mm Hg) before the 6′WT (from 116±18 to 108±18, P =0.004) and ET (from 116±15 to 108±17, P =0.001); the diastolic blood pressure before the 6′WT (from 69±9 to 63±11, P =0.01) and ET (from 70±8 to 65±10, P =0.004); and the Ve/Vco2 slope during the 6′WT (from 32±7 to 31±6, P =0.04) and ET (from 33±8 to 31±5, P =0.03). Sildenafil attenuated the HR increment during the 6′WT (P =0.003) and ET (P =0.000). Sildenafil increased the peak ˙ o2 from 16.6±3.4 to 17.7±3.4 mL/kg per min (P =0.025) and the exercise time from 12.3±3.4 to 13.7±3.2 minutes (P =0.003). Sildenafil improved most scores of International Index of Erectile Function. Conclusions—Sildenafil was tolerated and effective for ED treatment in CHF, and improved the exercise capacity. The reduction of HR during exercise with sildenafil could theoretically decrease the myocardial oxygen consumption during sexual activity.