Surface Electrocardiogram in the Detection of Myocardial Ischemia During Percutaneous Coronary Angioplasty

Abstract

The purpose of this study is to examine how frequently myocardial ischemia was manifested on the surface electrocardiogram (ECG) during percutaneous transluminal coronary angioplasty (PTCA) and to select the most sensitive leads for the duration of ischemic ST changes. The study population consisted of 126 patients (pts), 116 men and 10 women, who underwent PTCA for one-vessel coronary artery disease. A 12-lead ECG was recorded in all patients before inflations and at ten-second intervals during each inflation. ST segment deviation, R wave amplitude, and rhythm disturbances were analyzed on all ECG tracings. Ischemic ST changes occurred in 114 pts (90%), 80 with left anterior descending (LAD) artery occlusion, 22 with right coronary artery (RCA) occlusion, and 12 with left circumflex (LCX) artery occlusion (p < 0.01 LAD vs LCX, p < 0.01 RCA vs LCX). Angina pectoris occurred in 74 pts (59%) and coincided with ST changes in 68 of these pts (92%). No significant changes of R wave amplitude were found during balloon inflations. The most sensitive ECG leads for detection of ST elevation were V2 or V3, V4 and V 1 for the LAD, leads aVF and II for RCA, and leads III, aVF, or II, and V6 for LCX. The best leads for detection of ST depression were III, aVF and II for LAD, V2 or V3 and aVL for RCA, and V2 or V3, V1, and V4 for LCX. In conclusion, surface ECG represents a simple and very sensitive method for myocardial ischemia monitoring during PTCA. However, in laboratories in which a 12-lead ECG may not be available, a system of three appropriately selected leads for each coronary artery can be used to provide adequate accuracy.