Transient electrocardiographic changes of elective coronary angioplasty compared with evolutionary changes of subsequent acute myocardial infarction observed with continuous three-lead monitoring

The current use of continuous multilead monitoring with high-resolution digital systems 1 during clinically unstable situations has greatly augmented the versatility of the electrocardiogram. A recent study 2 of patients undergoing elective percutaneous transluminal coronary angioplasty (PTCA) reported multilead patterns of peak ST-segment elevation and depression that were reproduced by later reocclusion of the same coronary site. In related work, 3,4 detailed quantitative analyses of dynamic changes in the QRS complex and ST segment during PTCA-induced ischemia were presented in the most active lead of each patient. Occasionally an acute myocardial infarction (AMI) develops spontaneously in the hours after an elective PTCA. Use of continuous electrocardiographic monitoring would facilitate comparisons between the dynamic changes of the “controlled” ischemic period during the PTCA and the spontaneous ischemic period of the AMI by using each patient as his own baseline. Such information may provide a more complete understanding of the evolution of the acute ischemic process. Using continuous 3-lead monitoring in 4 carefully selected patients with elective PTCA who subsequently developed AMI, this study quantitates and compares dynamic characteristics of the ST segment occurring during both ischemic events.