Six months of Sildenafil therapy improves heart rate recovery in patients with heart failure

Previous research has demonstrated an increase in large vessel stiffness in patients with heart failure (HF). Furthermore, heart rate recovery (HRR) may be negatively impacted by increased arterial stiffness secondary to altered baroreceptor discharge. The purpose of the present study was to determine if chronic phosphodiesterase 5 (PDE5) inhibition with Sildenafil, previously shown to improve arterial stiffness, favorably impacts HRR in patients with HF. Forty male subjects (age: 65.3 ± 7.3 years, baseline ejection fraction: 37.1 ± 7.4%, 15 non-ischemic HF/25 ischemic HF) participated in this study. Subjects received Sildenafil (25 mg, 3 times/day) for six months. Symptom-limited exercise testing was performed at baseline and six months with a lower extremity ergometer. Heart rate recovery was defined as HR at maximal exercise minus HR at 1 min recovery. No adverse effects were reported throughout the study period. Paired t-testing revealed that HRR was significantly improved following six months of Sildenafil therapy (baseline: 17.5 ± 3.5 bpm vs. Post: 20.6 ± 3.2 bpm). The results of the present study indicate that chronic Sildenafil therapy significantly increases HRR, an important prognostic marker, in patients with HF. A plausible mechanism for the improvement of HRR is the previously demonstrated impact Sildenafil has on arterial stiffness and therefore baroreceptor function.