Diastolic heart failure: a separate disease or selection bias?

Chronic heart failure (CHF) is often subdivided based on left ventricular ejection fraction (LVEF) in 2 distinct forms, usually specified as "diastolic heart failure" and "systolic heart failure." In this review, arguments are provided against an LVEF-based bimodal view, and CHF is presented as one pathophysiological identity encompassing a continuous spectrum of closely related phenotypes. Most importantly, there is currently no pathophysiological basis to support a bimodal view. As a result, conceptual presentations of CHF, such as the vicious circle paradigm of CHF, become obsolete. Furthermore, the binary view of CHF is the unfortunate result of selection biases that has confounded practically all clinical trials of CHF. Unfortunately, current investigations still introduce selection bias when studying heart failure at preserved or reduced LVEF. Future investigations should analyze CHF as one disease and focus on the mechanisms through which disease modifiers such as sex, diabetes, and hypertension induce phenotypic diversity.