Picture of a cross section of the h

Picture of a cross section of the heart.
Left heart failure occurs when the left ventricle cannot pump blood to the body and fluid backs up and leaks into the lungs causing shortness of breath. Right heart failure occurs when the right ventricle cannot adequately pump blood to the lungs. Blood and fluid may back up in the veins that deliver blood to the heart. This can cause fluid to leak into tissues and organs.
It is important to know that both sides of the heart may fail to function adequately at the same time and this is called biventricular heart failure. This often occurs since the most common cause of right heart failure is left heart failure.