Your Heart

When working correctly, the heart pumps an average of 6 liters of blood every minute of your life through its four chambers:

• Two upper chambers, the atria, move blood returned from your body and lungs to the more muscular lower chambers.
• Two lower chambers, the ventricles, pump the blood back to the lungs and body.
• The right side of the heart is responsible for taking blood returning from the body and pumping it to the lungs where it is freshly oxygenated and waste gases are removed.
• The left side of the heart is responsible for taking freshly oxygenated blood from the lungs and pumping it to every cell in your body.

Your Heart's Circulatory Systems

Like all muscles, the heart requires a constant supply of fresh blood, carried through two main arteries (left and right main coronary arteries), which branch into major circulation systems that supply the left and right side of the heart.

The left main coronary gives rise to two arteries, the Left Anterior Descending (LAD) coronary artery and the Circumflex (Cx) coronary artery. The LAD services about 40% of the heart muscle commonly providing oxygen rich blood to the critically important left ventricle. Since it services the left ventricle, is the most important. It normally has at least one diagonal branch, plus numerous others that serve the septum, the wall between the left and right ventricles. The circumflex system serves the left lateral, or side, wall and the back, or posterior, of the left venticle, giving rise to several Obtuse Marginal (OM) branches that span out over its territory.

The right coronary artery has several branches. The Acute Marginal (AM) branch provides flow to the front of the right side of the heart. As it proceeds toward the apex of the heart, it splits into the Posterior Descending (PD) and Posterior Lateral (PL) branches, which provide the major circulation to the right ventricle and septum.

Blockages in the coronary arteries  arteries cause the heart muscle to become oxygen starved, or ischemic. Ischemic heart muscle cannot contract efficiently, which can result in heart attack and heart failure. The heart has pain sensors which serve to warn when it is ischemic. This pain is called angina and is a serious indication that something is wrong with the heart (though some people with ichemia have no pain).

Heart Valves

The heart has four valves, which ensure blood flows in only one direction.

• The tricuspid valve has three leaflets and lies between the right atrium and right ventricle. It's job is to keep blood from backing up into the atrium and allows it to flow into the right ventricle.

• The pulmonic valve also has three leaflets and ensures that blood pumped by the right ventricle proceeds in a forward direction through the lungs. For adults, surgery on the pulmonic valve rarely needed.

• The mitral valve has two leaflets and assures that oxygenated bloodfor ensuring that blood returned from the lungs flows in one direction from the right ventricle into the left ventricle.

• The aortic valve has three leaflets and sits at the exit from the left ventricle where the aorta meets the heart. It ensures that blood leaving the heart heads downstream to the body.

Problems with the heart valves disrupt the circulation and can lead to life-threatening conditions. Fortunately, the damage usually occurs slowly and can  be managed medically in the early stages. Some valve problems are congenital (you were born with them) while others are acquired in later life. Some faulty valves can be repaired while others must be replaced.