Patient Education Library

Angina

Angina (pronounced an-ji-na) or angina pectoris is produced when the supply of oxygen that is carried by blood is unable to meet the demands of the heart muscle. The decreased supply of blood is created by an obstruction within the coronary artery which impedes blood flow across it. Atherosclerosis is the commonest cause of obstruction. However, obstruction may also result from coronary artery spasm or the use of "crack" cocaine.

Angina pectoris is a recurring symptom and usually occurs in the form of chest discomfort (tightness, fullness, squeezing, heaviness, burning or pain) in the center of the chest and /or over the left breast). The discomfort may move to the left shoulder and arm (although it may move to both shoulders/arms, throat, jaw, or even the lower portion of the chest or upper abdomen). It may be accompanied by shortness of breath, sweating, weakness, dizziness or nausea, or numness in the shoulders, ams and hands. . When the build up of the plaque is gradual, the patient's symptoms are relatively predictable and stable. Such patient's usually have symptoms that are provoked by specific level of exercise. It is genearlly brief, lasts only 2-3 minutes and subsides promptly with cessation of exercise or following the use of a nitroglycerin tablet. This pattern of pain is known as stable angina. The partial and temporary decrease in oxygen supply to the heart muscle does not generally cause peranent damage (unlike a heart attack).

Some patients may have atypical (not typical) symptoms. For example, the pain may be confined to left shoulder, throat, jaw or bewteen the shoulder blades. Others may have shortness of breath or sudden weakness, while approximately 10% may have no symptoms even when the heart is severely stressed or undergoing a heart attack. Such patients are said to have a defective warning system. Diabetic patients are more prone to have atypical or no symptoms.
 
Because there are several causes of chest pain that are unrelated to the heart, many patients tend to ignore their symptoms attributing it to heart burn, mitral valve prolapse, a gall bladder attack, muscle sprain, etc. If you have risk factors for coronary artery disease and are having unsual symptoms suggestive of angina or a heart attack, make sure that you consult your doctor about your complaints.

The various phases of Atherosclerosis have been described in another section. It begins with the deposition of fatthy streaks on the inner lining of the artery. Additional deposits lead to a bulky atheroma that begins to encroach into the channel of the coranary artery. Fibers begin to grow into the atheroma causing harder plaques. The plaque of atherosclerosis may develop a crack on its surface. This is known as plaque rupture which can result in the deposit of a blood clot at the site of the blockage. If the blood clot totally blocks flow to the heart muscle, a heart attack usually results.

However, if the clot causes a partial blockage, the patient may develop unstable angina. Such patients have prolonged, frequent and more severe episodes of angina. The discomfort may be the patient's first symptom (in which case it is called new onset angina). In other cases, stable angina gradually or suddenly changes into a pattern of unstable angina.

The chest discomfort of unstable angina may become more frequent, lasts longer, is more intense, brought on by lesser degress of exertion (compared to prior symptoms), appears at rest or even awakens the patient from a sound sleep. It is called unstable angina because many untreated patients end up having a heart attack. Unstable angina may also occur in the absence of a blood clot, if the severity of the blockage (due to the atheroma and plaques) becomes severe enough to cause a drastic decrease in blood supply to the heart muscle.

Click here to review the Medical Treatment of Angina