Origin of QS complexes in hypertrophic cardiomyopathy and acute myocardial infarction

: Superficial cardiac ECG mapping was performed to examine 16 patients with acute myocardial infarction and 13 with hypertrophic cardiomyopathy who had electrocardiographic signs of focal myocardial changes (QS complex and/or abnormal Q wave). Deviation of instantaneous ventricular depolarization vectors in the direction opposite the malfunctioning myocardial portion that had partially or completely lost its electric activity was found to underlie the formation of QS complex in patients with acute myocardial infarction. In some patients with hypertrophic cardiomyopathy, an abnormal QS complex is attributed to sharp changes in central and end instantaneous depolarization vector orientation in the direction of the most hypertrophic septal portions, the location of a QS areas corresponding to variants of asymmetric septal hypertrophy.