The ECG records electrical impulses of the heart which indicates that the heart muscle is not getting as much oxygen as it needs (“Ischemia”); they may also indicate abnormalities in heart rhythm or some of the other possible abnormal features of the heart. For many patients with angina, the ECG at rest is normal because the symptoms of angina occur during stress. Therefore, the functioning of the heart may be tested under stress, typically exercise. In the simplest stress test, the ECG is taken before, during, and after exercise to look for stress–related abnormalities. Blood pressure is also measured during the stress test and symptoms are noted.
The stress test
A more complex stress test involves picturing the blood flow pattern in the heart muscle during peak exercise and after rest. A tiny amount of a radioisotope, usually thallium, is injected into a vein at peak exercise and is taken up by the normal heart muscle. A radioactivity detector and computer record the pattern of radioactivity distribution to various parts of the heart muscle. Regional differences in radioisotope concentration and in the rates at which the radioisotopes disappear are measures of unequal blood flow due to the coronary artery narrowing, or failure of uptake in scarred heart muscle.
X–rays of the coronary arteries (Coronary “Arteriogram” or “Angiogram”)
The most accurate way to assess the presence and severity of coronary disease is a coronary angiogram, an x–ray of the coronary artery. A long thin flexible tube (a “Catheter”) is threaded into an artery in the groin or forearm and advanced through the arterial system into one of the two major coronary arteries. A fluid that blocks x–rays (a “Contrast medium” or “Dye”) is injected. X–rays of its distribution show the coronary arteries and their narrowing.
Treatment of Angina Pain
First of all controlling existing “Risk factors” of angina pain is important. These include high blood pressure, cigarette smoking, high blood cholesterol levels, and excess weight. If the doctor has prescribed a drug to lower blood pressure, it should be taken as directed. Advice is available on how to eat to control weight, blood cholesterol levels, and blood pressure. A physician can also help patients to stop smoking. Taking these steps reduces the likelihood that coronary artery disease will lead to a heart attack.
Secondly, controlling physical activity, adopting good eating habits, moderating alcohol consumption, and not smoking are some of the precautions that can help patients live more comfortably and with less angina. For example, if angina comes on with strenuous exercise, exercise a little less strenuously, but do exercise. If angina occurs after heavy meals, avoid large meals and rich foods that leave one feeling stuffed. Controlling weight, reducing the amount of fat in the diet, and avoiding emotional upsets may also help.
Angina is often controlled by drugs which relieves pain by widening blood vessels. This allows more blood to flow to the heart muscle and also decreases the work load of the heart. Beta blockers slow the heart rate and lessen the force of the heart muscle contraction. Calcium channel blockers are also effective in reducing the frequency and severity of angina attacks. If medication fails to control angina then surgery or angioplasty is recommended.
Coronary artery bypass surgery is an operation in which a blood vessel is grafted onto the blocked artery to bypass the blocked or diseased section so that blood can get to the heart muscle. An artery from inside the chest (an “internal mammary” graft) or long vein from the leg (a “Saphenous vein” graft) may be used.
Balloon angioplasty involves inserting a catheter with a tiny balloon at the end into a forearm or groin artery. The balloon is inflated briefly to open the vessel in places where the artery is narrowed. Other catheter techniques are also being developed for opening narrowed coronary arteries, including laser and mechanical devices applied by means of catheters.