Harvard Health Letter

Understanding the ECG: Reading the waves

The electrocardiogram (ECG) is one of the most common, enduring, and important tests in all of medicine. It's easy to perform, noninvasive, produces results right away, and is useful in diagnosing dozens of heart conditions. The ECG has taken on even more importance lately because a particular ECG pattern, called ST elevation, is a strong indication that a serious heart attack has occurred, and there's more emphasis than ever on treating heart attacks as soon as possible. An ECG isn't necessarily going to be part of a routine physical, but if you need medical attention because you have chest pain, sudden unexplained shortness of breath, or other symptoms that suggest a possible heart attack, you will almost certainly get an ECG.
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