HEART

The heart has four chambers: two on one side, making up one pump, which is divided by a wall of muscular tissue (known as the septum) from two chambers on the other side which make up the second pump.

The upper chamber on each side is called the atrium (hence the left and right atrium). The lower chamber is the ventricle (the left and right ventricle).

Blood first flows into the atrium. It then passes into the larger and more muscular ventricle which pumps the blood out.

The right ventricle is the pump for the lungs. The much stronger left ventricle drives the systemic circulation to the rest of the body.

Blood flow through the heart is controlled by a series of valves which are flaps of tissue which allow the blood to flow only forward.

If either of the pumps fails to do it’s work, heart failure is the result.

If the failure affects the right ventricle, blood dams up in the veins and tissues causing swelling of the legs - this is congestive cardiac failure.

If the ventricle is failing, blood stays in the lungs and makes them stiff so it becomes difficult to breathe. As the failure gets worse, less blood is pumped into the arteries so less and less exercise can be done. Eventually the patient is weak and tired even sitting down.

There are a number of causes of heart failure. Some involve the valves and can be corrected by surgery. Mostly, however, the heart muscle is damaged (most often by obstructive coronary artery disease due to atherosclerosis) and can’t pump properly - changes are mostly not reversible by surgery - although drug treatment often helps. The only way of replacing the failing heart is by a transplant.