Electrocardiographic ischemic ST-T changes and ventricular premature systoles

41928 consecutive electrocardiograms were statistically analyzed for the presence of ventricular premature systoles (VPSs) and ischemic ST-T changes in different age groups. VPSs were found in 2314 tracings, whereas signs of myocardial ischemia were noted in 10448 records. VPSs appeared to be more prevalent in the presence of ischemic changes than in the absence of ischemia, and those VPSs in cases with ischemic changes showed a higher correlation with aging. 456 electrocardiograms were then selected to correlate the morphology of VPSs and the areas of myocardial ischemia based on the following criteria: (1) VPSs with the same morphology were present in both limb and precordial leads, and (2) only one representative record was used on each patient who had more than one tracing showing VPSs. It was found that, especially in cases with inferior or anterolateral wall ischemia, right bundle branch block (RBBB) type VPSs appeared to arise from these ischemic areas, whereas such a correlation was less evident in left bundle branch block (LBBB) type VPSs. Although LBBB type VPSs were generally considered benign, those with superiorly oriented QRS axes appeared to be more closely associated with organic cardiac lesions than those with inferiorly oriented axes. Clinical significance of the morphology of VPSs may thus be substantiated.