Heart failure. A proposed definition and classification.

Heart failure exists when either the systolic or diastolic operation of the ventricle is impaired to a degree that, despite compensatory mechanisms, the demands of the peripheral organs are not satisfied, the peripheral muscle shortens inadequately, and/or the pulmonary or systemic venous system becomes congested from high filling pressures. Since every pumping system has finite limits and can fail if excessive and prolonged demands are made on it, any definition of failure must take into consideration the degree of stress imposed and whether or not the cardiac response is appropriate or subnormal. When failure is present, it becomes essential to discern whether it involves the intrinsic pumping structures of the heart, the myocardial cells, or, rather, whether failure of one of the other components of the integrated cardiovascular system (for example, valvular dysfunction, ruptured ventricular septum) has occurred.