The pathophysiology of heart failure with preserved ejection fraction.

Approximately half of all patients with heart failure have preserved ejection fraction (HFpEF) and, as life expectancies continue to increase in western societies, the prevalence of HFpEF will continue to grow. In contrast to heart failure with reduced ejection fraction (HFrEF), no treatment has been proven in pivotal clinical trials to be effective for HFpEF, largely because of the pathophysiological heterogeneity that exists within the broad spectrum of HFpEF. This syndrome was historically considered to be caused exclusively by left ventricular diastolic dysfunction, but research has identified several other contributory factors, including limitations in left ventricular systolic reserve, systemic and pulmonary vascular function, nitric oxide bioavailability, chronotropic reserve, right heart function, autonomic tone, left atrial function, and peripheral impairments. Multiple individual mechanisms frequently coexist within the same patient to cause symptomatic heart failure, but between patients with HFpEF the extent to which each component is operative can differ widely, confounding treatment approaches. This Review focuses on our current understanding of the pathophysiological mechanisms underlying HFpEF, and how they might be mechanistically related to typical risk factors for HFpEF, including ageing, obesity, and hypertension.