Heart & Vascular Program

About Your Heart

Your heart is a muscle that pumps blood to all parts of your body. It is approximately the size of your fist and is located in the centre of your chest, protected by your ribcage. Four chambers receive and pump blood through your arterial and venous systems (your arteries and veins). Walls separate the chambers, and the blood flows through valves that prevent backflow.

This is the pathway of blood flow through your heart:

1. Unoxygenated blood from the venous system is collected in the right atrium, the first chamber of the heart.

2. The blood flows from the right atrium through the tricuspid valve to the right ventricle, which is the second chamber. From there, the blood passes through the pulmonary valve to the lungs, where it picks up oxygen.

3. The oxygen-rich blood flows into the left atrium, the third chamber.

4. The blood flows from the left atrium through the mitral valve into the fourth and final chamber, the left ventricle. The left ventricle is known as the working chamber of the heart because it must be strong enough to pump blood to the entire body. The heart pumps the blood from the left ventricle through the aortic valve, and oxygen-rich blood is carried through the arteries to the body.

On the surface of your heart are two main coronary arteries and numerous smaller arteries. These arteries supply oxygen-rich blood to the heart muscle on a supply-and-demand basis. The right coronary artery supplies blood to the right side and back region of the heart. The left coronary artery branches into two arteries, the left anterior descending artery and the left circumflex artery, which supply the oxygen-rich blood to the left side, underside and the back portion of the heart.

With heart disease, atherosclerosis builds up and narrows the coronary arteries. There are often little or no symptoms until the artery becomes too blocked for oxygen-rich blood to reach your heart. When this happens, you may experience symptoms such as shortness of breath or chest pain. These symptoms are called angina.

A heart attack, also known as a myocardial infarction, occurs when an artery is completely blocked and the heart muscle dies from lack of oxygen. Heart attacks are usually caused by these blood clots. If you think you are having a heart attack, it is crucial to get to the nearest hospital as quickly as possible. You can be given blood-clot busting medication that can spare you from permanent damage to your heart.

If you are ever unsure whether you are having a heart attack, it is much better to be safe than sorry.