ABSTRACT
The resting electrocardiogram (ECG, EKG) is an invaluable, inexpensive, and easily performed noninvasive test, which can often lead one to suspect an otherwise unexplained or unrelated pathologic or physiologic cardiovascular derangement. When it is entirely normal, it means only that it is either totally normal or the underlying disease state has not as yet altered the ECG. Diseases in various stages of development or advancement can result in any number of ECG abnormalities. These include rhythm disturbances, conduction abnormalities, pseudo-scar Q wave development, pathologic Q waves, and, most frequently, ST and T wave changes. Abnormalities of the ST segment and T wave can be seen as depression of the ST segments below the baseline (isoelectric zone), decreases in T wave voltage and obvious T wave negativity. It can be aptly stated that any change from normal should be a cause for suspicion and observation, and these changes always have meaning, depending on the mechanism of production as caused by the underlying pathophysiologic alterations of the ECG during or after its interpretation by somebody who is competent and experienced in such matters.163
