Illustration of a cross-sectioned heart to demonstrate a heart failure. Visible are: the aorta (big, red), vene cava (big, blue), pulmonary arteries and veins (grey), atrium, ventricles, heart valves, myocardium and pericardium. In case of a failure, the heart muscles are not normally active anymore, so that rests of the blood remains inside the ventricles (not yet visible in this picture), which causes expansion of the ventricles. That can cause recesses or a heart enlargement. A heart failure is a non-sufficient function of the heart that is caused by a reduced pumping efficiency of the myocardium.
Heart failures are classified, according to their clinical severity, into 4 NYHA (New York Heart Association) stages. A rougher classification is made into: Compensated heart failure: Only causes discomfort under pressure. Decompensated heart failure: Causes discomfort in rest.
A further differentiation is made according to which part of the heart is affected: Right-sided failure: The right ventricle is affected. Left-sided failure: The left ventricle is affected. Biventricular failure: Both ventricles are affected.
A classificiation into acute or chronic heart failure is made according to the course of disease. Pathogenesis: The chronic heart failure is in most cases caused by a reduction of the contractile heart muscle tissue.