Wide band recording of the electrocardiogram and coronary heart disease

Wide band, high frequency electrocardiography employing an expanded time scale and both greater amplitude and a greater frequency response than conventional electrocardiographs reveals small notches in the QRS complex which are obscured in the conventional electrocardiogram. A total of more than three high frequency notches in Leads V4, V5, and V6 plus the notches in the three largest limb leads suggests a high probability of coronary heart disease. This criterion is a modification of one we previously reported in that now fewer leads need be examined and slurs are not counted. In a control group of 100 normal subjects and 76 subjects with coronary artery disease used to develop this new criterion, there were 8 false positives (8 per cent) and 5 false negatives (7 percent). The Health Evaluation Center group provided 966 new subjects who were studied using the high frequency technique; 875 were classified as normal; 11 per cent had an abnormal number of notches. Of 24 patients with histories of myocardial infarction, 79 per cent showed excess notching. Of 12 subjects with angina pectoris, 7 showed excess notching. Notching in the 35 patients with uncomplicated hypertension and in 20 subjects with hypercholesterolemia was within the normal range. Twenty-four additional Provident Mutual Life Insurance Company employees were added to our long term study. Of these, two developed coronary artery disease. Both exhibited serial changes in the high frequency electrocardiogram.