Understanding Angina

Angina is a condition marked by recurring pain or discomfort in the chest. It is usually described as a squeezing, pressure, heaviness, tightening or aching across the chest, particularly behind the breastbone. The pain sometimes also is felt in the shoulders, arms, neck, jaws or back.

The heart muscle -- like all areas of the body -- needs a regular supply of blood. When the blood supply doesn't meet the demand, the result is a condition called myocardial ischemia. The most common cause of myocardial ischemia is coronary artery disease. In coronary artery disease, blood vessels that carry blood to the heart muscle become narrowed and blocked because of arteriosclerosis, a build up of fat deposits or "plaque" on artery walls. Angina is a symptom of this condition. 

During an angina episode, the lack of oxygen -- called ischemia -- is usually temporary and reversible. Once the oxygen supply to the heart muscle is restored, the chest pain disappears. The pain does not mean that the heart muscle is suffering irreversible, permanent damage. Episodes of angina seldom cause permanent damage to heart muscle.

Angina is divided into three types:

• Stable angina, the most common type, occurs when the heart is working harder than usual. This can occur during physical exertion or emotional stress; extreme cold or heat; and after eating a heavy meal or drinking alcohol. It can also occur with cigarette smoking.

• Unstable angina is a very dangerous condition that requires emergency treatment. It is a sign that a heart attack could occur soon. It is caused by blood clots that partially or totally block an artery. The clot may grow large enough to completely block the artery and cause a heart attack, or it may partly dissolve, and later form again. Chest pain can occur each time a clot blocks an artery. Unlike stable angina, it does not follow a pattern.

• Variant angina. Variant angina is rare. It is caused by a spasm in a coronary artery, and it usually occurs at rest. It can occur in people who do not have coronary artery disease.

Not all chest pain or discomfort is angina, but all chest pain should be checked out by a doctor.  Chest pain or discomfort can be caused by a heart attack, lung problems such as an infection or a blood clot, musculoskeletal problems, heartburn or a panic attack.

Symptoms

The symptoms of angina depend on its type:

• In stable angina, the pain or discomfort occurs when the heart muscle works harder than normal. Therefore, the pain is expected, and the episodes of pain tend to be alike. Pain usually lasts less than 15 minutes, may spread to the arms, or other areas, and is relieved by rest or medication.

• In unstable angina, the pain or discomfort often occurs at rest, while sleeping or with little physical exertion. It is unexpected, more severe and lasts up to 30 minutes. It is usually not relieved by rest or medication. It can get worse as time passes.   

• In variant angina, the pain can be severe and usually occurs between midnight and early morning. It is usually relieved by medication.

How is angina treated?

The goals of angina treatment are to decrease the attacks and severity of symptoms, and to prevent heart attacks.

The first priority is treating the underlying coronary artery disease that causes angina. This is done by controlling existing risk factors, including high blood pressure, cigarette smoking, high blood cholesterol levels and excess weight. If you have diabetes, your health care provider will stress keeping your blood sugar under good control.

Physicians often prescribe medication to treat angina. The most commonly prescribed drug for angina is nitroglycerin, which belongs to a group of drugs called nitrites. These drugs provide temporary relief of chest pain by widening blood vessels, allowing more blood to flow to the heart muscle and decreasing the heart's workload. Oral or sublingual nitroglycerin is prescribed for angina attack and is not a long-term therapy. Nitroglycerine is also available as a dermal patch and a long-acting oral medication; these can reduce the incidence and severity of angina over a 12- to 24-hour period.

Other treatments for angina include calcium channel blockers and beta blockers that reduce blood pressure. Calcium antagonists lower blood pressure by reducing calcium entry into vascular smooth muscle cells, relaxing blood vessels. Beta blockers slow heart rate and reduce the heart's output of blood.

Your health care provider will look at your medical history and other needs to find the right regimen to treat your angina.

If controlling risk factors and medication do not reduce the frequency of angina attacks, your health care provider may recommend balloon angioplasty, a procedure to widen narrowed arteries, or coronary artery bypass graft surgery to improve blood supply to the heart muscle.