Echocardiographic Evaluation of Left Ventricular Contractility

Abstract

The systolic performance of the left ventricle (LV) is determined by the interaction between preload, afterload, the contractile state of the myocardium, synergy of contraction and heart rate. Studies in isolated cardiac muscle have shown a direct dependency of fiber shortening (or contractile element shortening) on preload and contractile state and an inverse dependency on afterload [1]. Studies in the intact heart have shown a similar dependency of cardiac performance on loading so that, at present, no single measurement of myocardial performance is capable of reflecting contractile state completely independent of preload and afterload [2–5]. An index of cardiac inotropism would have important clinical and research applications since it would allow comparison among individual patients, early detection of myocardial dysfunction (prior to pump dysfunction) in a wide range of cardiac diseases, and evaluation of pharmacologic and surgical interventions on myocardial contractility.