In the Program on Surgical Control of the Hyperlipemias, the implication for left ventricular function of the disappearance of Minnesota electrocardiographic Q-QS codes was studied in 813 subjects with one healed myocardial infarction. Electrocardiograms done at the time of the myocardial infarction and electrocardiograms and left ventriculograms done at randomization were analyzed. Subjects were divided according to their electrocardiograms into three groups: Group I, Minnesota Q-QS codes developed with the myocardial infarction and persisted (n = 474); Group II, Q-QS codes developed with the myocardial infarction but subsequently disappeared (n = 219); and Group III, Q-QS codes did not develop with the myocardial infarction (n = 120). The data showed that the severity of impairment of left ventricular function was associated in decreasing order as follows: Groups I, II and III (p < .00001). For Group I, impairment of left ventricular function was directly related to the level of significance of the Q-QS codes recorded in the healed state. For Group II, left ventricular function did not correlate with the significance of the code recorded with the myocardial infarction and approximated that present in Group III, suggesting that complete healing had transpired.