INFERIOR WALL ACUTE MYOCARDIAL-INFARCTION WITH ONE-LEAD ST-SEGMENT ELEVATION - ELECTROCARDIOGRAPHIC DISTINCTION BETWEEN A BENIGN AND A MALIGNANT CLINICAL COURSE

Background: In most clinical trials, ST-segment elevation in two conti guous leads is required for diagnosis of acute myocardial infarction ( AMI). This study describes the clinical course of patients with inferi or wall AMI with one-lead ST-segment elevation in lead L3 in the initi al ECG. Methods: Of 394 consecutive patients with inferior wall AMI, 3 1 (7.8%) had an initial ECG showing ST-segment elevation (greater than or equal to 1 mm) only in lead L3 (ST < 1 mm in leads L2 and aVF) and upright T waves in inferior leads. Patients were categorized into thr ee groups: (I) no precordial ST-segment depression (n = 6), (II) maxim al precordial ST-segment depression in leads V1-V3 (n = 4), and (III) maximal precordial ST-segment depression in leads V4-V6 (n = 21). Resu lts: Patients in group III developed severe heart failure (pulmonary e dema or cardiogenic shock) six times more frequently than those in gro ups I-II (62 versus 10%). Among patients who underwent coronary angiog raphy, three-vessel coronary artery disease (>50% stenosis) was more c ommon in group III. Five of six patients in group III who underwent em ergency angioplasty of the right coronary artery because of cardiogeni c shock survived. Conclusion: Patients with inferior wall AMI and an i nitial ECG with ST-segment elevation only in lead L3, and maximal prec ordial ST-segment depression in leads V4-V6, are at risk of severe com plications, especially heart failure, but their clinical course may be ameliorated by employing an aggressive interventional strategy.