Value of premature ventricular contraction morphology in the detection of myocardial infarction

Summary A ventricular premature contraction (VPC) with a QR pattern has been associated with antecedent myocardial infarction. In order to determine the validity of this sign, we compared the presence of localized abnormal wall motion during left ventricular angiography with the morphology of VPC's induced in each patient by catheter stimulation of the left ventricular endocardium. The morphology of V 1 was compared with anterior wall infarction, and of AVF with inferior wall infarction, and the specificity, sensitivity and predictive value of the QR VPC evaluated. A QR pattern VPC in V 1 with a Q≥0.04 sec and a Q/R ratio=0.20 had a specificity of 0.93, a sensitivity of 0.24 and a predictive value of 0.72 in the detection of anterior myocardial infarction. The detection rate was considerably increased with a Q/R ratio of ≥0.1 and specificity remained high at 0.87. Detection of inferior infarction by use of AVF was less certain, and is probably of limited value.