ELECTROCARDIOGRAM

March 23, 2009, 5:03 am

Heart function can be evaluated in a number of ways. A physical examination and a chest X-ray are crucial. However, different types of electrocardiograms (ECGs, sometimes abbreviated EKGs) give information that cannot be obtained by any other means.

A muscle in the heart receives its stimulation from an electrical system that governs how the heart beats. An electrocardiogram records the contraction of the muscle and the electrical impulses. By studying the ECG patterns and changes, physicians can diagnose many heart disorders.

An ordinary electrocardiogram takes about five minutes and is completely painless and has absolutely no danger. It is done either routinely to make a record for future reference or at the time of a suspected heart disturbance. Because an electrocardiogram records only a few moments of your heart’s action, it may fail to reveal abnormalities that occur infrequently or episodically, such as an irregular heart rhythm. It may be necessary, if you have had a heart attack or have an irregular heart rhythm, to repeat tracings frequently to observe any changes.

Your physician may want to have an ambulatory cardiogram, which means you carry a small, portable recording device (called a Holter ambulatory monitor) that continuously traces your heart’s rhythm over an extended period, usually twenty-four hours. This monitor is more likely than an ordinary ECG to reveal an episodic change in heart rhythm that may be the cause of dizziness or fainting spells. Although somewhat less convenient than a standard ECG, this tracing over time can supply invaluable information about the cause of unusual symptoms. Sometimes the attacks are so infrequent that it may take more than one tracing before the diagnosis can be made. It may also be repeated to see if treatment is effective.

Some people have chest pain that is not typical of angina pectoris. The standard ECG, which is taken while you are resting, may not reveal any abnormalities, so cardiographic tracings may be taken while you exercise in a carefully controlled situation. This is called an exercise or stress ECG. The tests involve riding a stationary bicycle or walking at increasing speeds on a moving ramp. Electrocardiogram wires will be attached and a technician and a physician will supervise the examination and interpret the results.

The only danger of this test is that you may experience an episode of angina pain during the procedure. However, it is certainly safer to have an attack under supervision so that a definite diagnosis can be made than to experience attacks when you are alone. Sometimes this test may be repeated after you have been given treatment for your anginal symptoms or after a heart attack.

The results of this test are not completely foolproof. You may have a normal test and still suffer from coronary disease. Occasionally, a test appears to indicate heart disease in a person who is normal. The examination itself is only one part of the total evaluation of heart disease. Your doctor will interpret all the tests together before he makes a diagnosis and decides on treatment.

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