The Heart & Vascular Center

Anatomy of the heart, and of heart disease

The heart is a muscular organ composed of four chambers; two upper chambers called atria and two lower chambers called ventricles. These four chambers and their four valves are responsible for pumping blood through the body in a rhythmic, life-giving pattern.

Deoxygenated blood enters the heart via the right atrium, flows into the right ventricle via the tricuspid valve, and is pumped through the pulmonary semilunar valve to the lungs. There, carbon dioxide is released and oxygen is replenished. The blood then returns to the heart via the left atrium, flows through the mitral (bicuspid) valve into the left ventricle, and is pumped through the aortic semilunar valve into the aorta. From the aorta, the blood is pumped through 60,000 miles of blood vessels. What one feels as a "heartbeat," or pulse, is the culmination of one cardiac cycle, and, in the healthy individual, this occurs over 100,000 times a day.

Although the heart is full of blood, it cannot receive oxygen and nutrients from the blood inside the chambers. The heart muscle must rely on the arteries on the surface of the heart to nourish it and keep it working properly. These surface arteries are known as the coronary arteries. There are three main coronary arteries: the right coronary artery, the left anterior descending coronary artery and the circumflex coronary artery. These three arteries branch into thousands of small arteries like a tree trunk brunches into limbs, bringing oxygen and nutrients to the heart muscle cells.

Anatomy of heart disease

Heart disease is actually a very comprehensive term that refers to any disorder that interferes with proper cardiac circulation. This includes defective heart valves, muscle disease, rhythm disturbances, and congenital defects (abnormalities of the heart that are present at birth). When most people refer to heart disease, they are probably referring to Coronary Artery Disease (CAD), which is the leading cause of death in the United States.

This is a normal coronary artery. The lumen is large, without any
narrowing by atheromatous plaque. The muscular arterial wall is of normal proportion.

The coronary artery shown here has narrowing of the lumen due
to build up of atherosclerotic plaque. Severe narrowing can lead to angina, ischemia, and infarction.

Coronary Artery Disease (CAD)

Over time, the coronary arteries can become built up with fat, cholesterol and calcium. The build up keeps the coronary arteries from functioning properly, and interferes with the delivery of an adequate supply of blood to the heart muscle. More than 95 percent of all coronary artery disease is due to atherosclerosis, the build up of fatty substances (cholesterol and triglycerides). Angina pectoris and myocardial infarction (chest pain and heart attack)

When the heart muscle does not get enough oxygenated blood to meet its demands, it experiences a hunger for more oxygen. This hunger is felt by the patient as a tightening, pressure, or fullness in the chest we term angina pectoris. Sometimes, the narrowed artery leading to an area of the heart can become completely blocked, causing a heart attack (myocardial infarction).

There are numerous treatments, both medical and surgical, available to patients with Coronary Artery Disease. In order to determine which treatment options are best for you, the physician will utilize several diagnostic tests, including stress testing, cardiac ultrasound, and cardiac catheterization.