INSTABILITY OF ST SEGMENTS IN THE EARLY STAGES OF ACUTE MYOCARDIAL-INFARCTION IN PATIENTS UNDERGOING CONTINUOUS 12-LEAD ECG MONITORING

Many patients presenting to the emergency department with suspected ac ute myocardial infarction (AMI) have an initial 12-lead eleetrocardiog ram (EGG) nondiagnostic for acute injury and thus do not meet any acce pted ECG criteria for thrombolytic therapy. Early studies in the use o f intracoronary thrombolytic therapy documented that cyclic variations in ST segment magnitudes between normalcy and injury are common durin g the early phase of AMI and correspond to spontaneous intermittent co ronary opening and reocclusion, The reliance on a single EGG to diagno se AMI may mean that many patients with AMI are missed if the initial ECG is obtained during a window of ST segment normalcy. We present 3 p atients with AMI who underwent continuous 12-lead ST segment monitorin g with frequent serial ECGs whose ST segments periodically normalized during the acute injury phase. We believe continuous 12-lead ST segmen t monitoring with frequent serial ECGs can aid the physician in identi fying patients with AMI who may benefit from thrombolytic therapy and other urgent revascularization techniques. ((C) 1995 by W.B. Saunders Company)