Myocardial function in heart failure.

Overt cardiac failure usually presents with constant clinical features as consequences of the reduced pump action, associated with an increased adrenergic drive, independent of the underlying disease. However, the study of left ventricular function, before and during the phase of cardiac insufficiency, shows that different pathophysiological mechanisms are responsible for the symptoms and signs of reduced cardiac action. It is possible to recognize that cardiac failure is caused primarily by: (1) early severe depression of the inotropic state, i.e. dilated cardiomyopathies; (2) late inadequate level of ventricular hypertrophy, with normal contractility, i.e. aortic stenosis; (3) early inadequate level of hypertrophy and slightly reduced inotropic state, i.e. mitral insufficiency, and (4) late inadequate level of hypertrophy and severe progressive reduction in contractility, i.e. aortic insufficiency. The possibility of an 'in vivo' assessment of the different determinant parameters of left ventricular function (contractility, afterload, preload, fiber and chamber compliance) through echocardiography enables a better understanding of the mechanisms leading to the cardiac failure and a more efficient therapeutic approach.