Suppression of Premature Ventricular Complexes with the PDE5 inhibitor Sildenafil: First clinical experience

The Phosphodiesterase-5 inhibitor, Sildenafil, suppresses ventricular arrhythmias in a sheep model of drug-induced long QT. In that study ventricular arrhythmias were abolished by reducing premature ventricular complexes (PVCs) and delaying PVC onset, thus preventing ‘R-on-T’ ventricular tachycardia. Evidence for effects in humans with arrhythmias is lacking. In this case study a 50 year-old female with a history of PVCs and systemic sclerosis was started on Sildenafil for Raynaud's phenomenon in line with current treatment recommendations. During initiation, the patient wore a 7-day cardiac monitor. Two subtypes of PVC were observed; one distinct morphology arising < 400 ms from the preceding sinus beat (‘early’), and a separate morphology >400 ms from the preceding sinus beat (‘late’). Sildenafil abolished late PVCs, and substantially reduced the frequency of early PVCs. Of those early PVCs remaining in Sildenafil, PVCs arose later in the cardiac cycle, 21 ms further from the preceding T wave apex. During washout, PVCs returned in frequency and timing towards baseline values. We report the first case suggesting an antiarrhythmic property of Sildenafil in a human.