Heart failure occurs when the heart can't pump blood as well as it should. It can affect either the left side of the heart (left-sided heart failure) or the right side (right-sided heart failure).

The heart’s right and left sides perform different jobs to keep blood moving through the body. When either side becomes too weak or stiff to function effectively, the result may be heart failure.

Heart failure happens when the heart is unable to pump blood around the body efficiently. The most common symptoms of heart failure are shortness of breath, fatigue, cough, and general weakness.