THE APEX CARDIOGRAM IN ISCHAeMIC HEART DISEASE

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Abstract
Changes in the apex cardiogram were studied in 59 patients with ischemic heart disease, of whom 25 had had a myocardial infarction and 34 either angina or an abnormal ecg response to exercise. Fifty-two normal subjects were used as a control group. The apex cardiogram "a" wave was thought to represent the pulse wave originating in the ventricle from the impact of blood against the ventricular wall as a result of atrial systole. An abnormal "a" wave was not present in normal subjects but was found in nearly all patients with ischemic heart disease, thus indicating an abnormal ventricular filling during atrial contraction. These changes were attributed to abnormally high ventricular resistance to atrial systole. The percentage amplitude of the "a" wave in relation to the total amplitude of the tracing in the normal subject was found to be 7.8 [plus or minus] 1.4%, and in the group with ischemic heart disease, 25.5 [plus or minus] 3.4%. The effect of exercise was studied in 25 patients with ischemic heart disease and in 32 normal subjects. There was significant increase in the amplitude of the "a" wave after exercise in all patients with arteriosclerotic heart disease. There were two "false-positive" responses to exercise in the control group. Nitroglycerine given to 27 patients with ischemic heart disease produced complete disappearance of the "a" wave in 11, significant reduction in amplitude in 12, and no change in 4 patients. In 10 normal subjects, there was also reduction in the amplitude of the "a" wave. In 14 patients, the administration of nitroglycerine before exercise prevented the appearance of the previously abnormal post-exercise "a" wave. It is concluded that this simple and easy method is useful to detect the abnormal mechanism of the ventricular filling in patients with ischemic heart disease.