In general terms, coronary artery disease means any illness that affects the heart’s coronary arteries (arteries that supply blood to the heart muscle). More specifically, coronary artery disease often is used interchangeably with coronary atherosclerosis, a build up of fatty deposits and fibrous tissue (plaques) inside the walls of the coronary arteries. Coronary atherosclerosis eventually can cause significant narrowing of the coronary arteries, decreasing the blood supply to portions of the heart muscle and triggering a specific type of chest pain called angina. Also, if a thrombus (blood clot) should form inside a narrowed coronary artery, the result is a myocardial infarction or heart attack, with the potential for significant damage to the heart muscle. Because coronary artery disease means coronary atherosclerosis in most patients, the risk factors for coronary artery disease are basically the same as those for atherosclerosis. Patients must remember, however, that atherosclerosis can affect more than just the coronary arteries. The arterial narrowing and/or damage caused by atherosclerosis is also a significant cause of stroke, aortic aneurysm and poor circulation to the extremities, bowel and kidneys.
Although the most common symptom of coronary artery disease is the chest pain called angina, it is possible for patients to have significant coronary artery disease without any symptoms at all. In these asymptomatic (showing no symptoms) patients, the only sign of coronary artery disease may be a suspicious change in the pattern of an electrocardiogram (EKG) recorded at rest or during an exercise stress test (a specialized recording of EKG during exercise). The stress test is able to uncover the coronary artery abnormality because exercise increases the heart muscle’s demand for blood, a demand that can’t be met when the coronary arteries are significantly narrowed. In areas of the heart affected by narrowed coronary arteries, the heart muscle starves for blood and oxygen, and its electrical activity changes. This altered electrical activity is reflected in the patient’s EKG tracing.
Unfortunately, some asymptomatic patients with significant coronary artery disease never have the problem discovered. In these patients, the first symptom of coronary artery narrowing may be the severe chest pain of a heart attack. If a heart attack occurs, the patient has a 15 percent chance of dying before receiving medical attention.
In most patients, however, the most common symptom of coronary artery disease is angina, also called angina pectoris. Angina usually is described as a squeezing, pressing or burning chest pain that tends to focus either in the center of the chest or just below the center of the rib cage. It also can spread to the arms (especially the left), abdomen, neck, lower jaw or neck. Other symptoms can include: sweating; nausea; dizziness or lightheadedness; breathlessness; or palpitations (often associated with the symptoms of a heart attack). Sometimes, when coronary artery disease produces burning chest pain and nausea, a patient may mistake their heart symptoms for indigestion.
Doctors divide angina into two types ù stable and unstable ù based on the symptom pattern and predictability. In stable angina, chest pain adheres to a specific predictable pattern, usually occurring after extreme emotion, overexertion, a large meal, cigarette smoking or exposure to extreme hot or cold temperatures. Symptoms usually last one to five minutes and they disappear after a few minutes of rest. In unstable angina, the symptoms are less predictable and more serious. Patients with unstable angina typically show one of the following patterns: a history of less than two months of angina, with three or more episodes daily; after a period of stable angina, symptoms suddenly become more severe, last longer or develop after less stress or exercise; or angina that begins when the patient is resting.
Diagnosing Coronary Artery Disease
Your doctor will ask about your family’s history of heart disease, your personal medical history, your current symptoms and any medications you are taking. Your doctor also will try to define the specific pattern of your angina symptoms ù whether your angina is stable or unstable.
Your doctor may suspect that you have coronary artery disease based on your medical history and the pattern of your symptoms. To confirm the diagnosis, he or she will perform a physical examination, with special attention given to your chest wall and heart, together with diagnostic cardiac testing. During the physical examination, your doctor will check for signs of chest wall tenderness ù usually a sign of a non-cardiac problem involving chest wall muscles, ribs or rib joints. Your doctor also will use a stethoscope to listen for any abnormal heart sounds. The physical examination will be followed by one or more diagnostic tests either to rule out angina or to determine the presence and severity of any underlying coronary disease.