Physiology of left ventricular diastolic function

Abstract

Left ventricular diastolic function in vivo is still incompletely understood. Extrapolations from in vitro studies are limited mainly owing to the simultaneous occurrence of relaxation and filling in vitro and the presence of haemodynamic loading conditions. The limited understanding of physiological mechanisms is contrasted by a vast number of ‘indices of diastolic function’, many of which originate from ad hoc empirical descriptions of data. At present, no absolute value of any index can discriminate between healthy patients and patients with severe cardiac disease. Moreover, the possibility of load-dependence is commonly ignored in the interpretation of alterations in indices of diastolic function. Future research should focus on the unveiling of physiological principles. It is hoped that an improved insight into the underlying mechanisms of diastolic function in vivo will ultimately lead to the development of meaningful indices that allow assessment and guidance of therapy in patients with cardiac disease.