Type 5 phosphodiesterase inhibition in heart failure

The possibility that selective inhibition of type 5 phosphodiesterase (PDE5) might be helpful in heart failure (HF) is currently receiving attention. This approach consistently and significantly reduces pulmonary vascular resistance (PVR) by inhibiting the hydrolysis of cyclic guanosine monophosphate in the pulmonary vasculature (2). As a result, right ventricular (RV) function and exercise capacity improve in patients with pulmonary hypertension (3,4). Based on the efficacy and safety of these compounds in that setting, several investigators have begun to study this class of therapy in patients with HF caused by left ventricular (LV) systolic heart failure (SHF). The creative and well-conducted study by Guazzi et al. (5) in this issue of the journal represents the latest of these investigations. The purpose of this Editorial Comment is to review this study, place it in the context of current knowledge, and suggest a possible next step in the investigation of the therapeutic potential of these interesting compounds for SHF.