SIGNIFICANCE OF ST SEGMENT ELEVATIONS IN POSTERIOR CHEST LEADS (V-7 TO V-9) IN PATIENTS WITH ACUTE INFERIOR MYOCARDIAL-INFARCTION - APPLICATION FOR THROMBOLYTIC THERAPY

Objectives. This study was designed to examine whether ST segment elev ation in posterior chest leads (V-7 to V-9) during acute inferior myoc ardial infarction ((MI) identifies patients with a concomitant posteri or infarction and whether these patients might benefit more from throm bolysis. Background. Because the posterior wall is faced by none of th e 12 standard electrocardiographic (EGG) leads, the ECG diagnosis of p osterior infarction is problematic and has often remained undiagnosed, especially in the acute phase. Methods. Eighty-seven patients with a first inferior infarction who were treated with recombinant tissue-typ e plasminogen activator were stratified according to the presence (Gro up A [46 patients]) or absence (Group B [41 patients]) of concomitant ST segment elevation in posterior chest leads V-7 to V-9. Results. Pat ients in Group a had a higher incidence of posterolateral wall motion abnormalities (p < 0.001) on radionuclide ventriculography, a larger i nfarct area (as evidenced by higher peak creatine kinase levels) (p < 0.02) and a lower left ventricular ejection fraction (LVEF) at hospita l discharge (p < 0.008) than those in Group B. ST segment elevation in leads V-7 to V-9 was associated with a higher incidence of at least o ne of the following adverse clinical events: reinfarction, heart failu re or death (p = 0.05). Although patency of the infarct-related artery (IRA) in Group A resulted in an improved LVEF at discharge (p < 0.012 ), LVEF was unchanged in Group B, regardless of the pateneg status of the IRA. Conclusions. ST segment elevation in leads V-7 to V-9 identif ies patients with a larger inferior MI because of concomitant posterol ateral involvement, Such patients might benefit more from thrombolytic therapy. (C) 1998 by the American College of Cardiology.