The CORONARY ARTERY MSEASE American Journal FEBRUARY 1, 1991, VOL. 67, NO. 4 of Cardiology1 Complete Atrioventricular Block Complicating Inferior Wall Acute Myocardial Infarction Treated with Reperfusion Therapy Peter Clemmensen, MD, Eric R. Bates, MD, Robert M. Califf, MD, Mark A. Hlatky, MD, Lynne Aronson, BS, Barry S. George, MD, Kerry L. Lee, PhD, Dean J. Kereiakes, MD, Gerald Gacioch, MD, Eric Berrios, RN, Eric J. Topol, MD, and the TAMI Study Group* Previous studies report larger myocardial infarcts and increrued in-hospital mortality rates in patients with inferior wall acute myocardlal infarction (AMI) and complete atrioventricular block (AV), but the clinical impliitionr of these complications in pa- tients treated with &don therapy have not been addressed. The clinical course of 373 pa- tients- SO (13%) of whom developed complete AV block- admitted with inferior wall AMI and given thrombolytic therapy within 6 hours of symp- tom onset was studied. Acute patency rates of the infarct artery after thrombolytic therapy were simi- lar in patients with or without AV block. Ventricu- lar function mearwed at baseline and before dis- charge in patients with complete AV block showed a decrement in medlan ejection fraction (-3.5 vs -0.496, p = 0.03) and in median regional wall mo- tion (-0.14 vs +0.24 standard deviations/chord, p = 0.05). The reocclusion rate was higher in pa- tients with complete AV block (26 vs 16%, p = 0.03). Patients with complete AV Mock had more episodes of ventricular fibrillation or tachycardia (36 vs 1496, p <O.OOl), sustained hypotension (36 VI lo%, p <O.OOl), pulmonary edema (12 vs 4%, From the Division of Cardiology, Department of Medicine, Duke Uni- versity, Durham, North Carolina; Division of Cardiology, Department of Internal Medicine, University of Michigan, Ann Arbor, Michigan; The Riverside Methodist Hospital, Columbus, Ohio; and the Christ Hospital, Cincinnati, Ohio. This study was presented in part at the American College of Cardiology, 38th Scientific Session,Anaheim, California, and supported in part by researchgrants from Genentech Inc., San Francisco,California, Abbott Laboratories, Chicago, Illinois and by Research Grants HS-05635 and HS-04873from the Agency for Health Care Policy and Research,Rockville, Maryland, by Research Grants HL-17670 and HL-36587 from the National Heart, Lung, and Blood Institute, Bethesda,Maryland, and by grants from the Robert Wood Johnson Foundation, Princeton, New Jersey. Manuscript re- ceived April 16, 1990,revised manuscript received and acceptedSep tember 26,199O. Addressfor reprints: Robert M. Califf, MD, Duke University Med- ical Center, Division of Cardiology, P.O. Box 31123,Durham, North Carolina 27710. *See Appendix. p = 0.02) and a higher in-hospital mortalii rate (20 VI 4%, p <O.OOl), although the mortality rate after hospital discharge was idsntlcal(2%) in the 2 groups. Multlvariable logistic regression analysis revealed that complete AV blodc was a strong inde- pendent predictor of in-hospital mortalRy (p = 0.0006). Thus, despite hdtial successfuireperfu- sion, patients with inferior wall AMI and complete AV block have higher rates of in-hospital complica- tions and mortality. (Am J Cardid 1661;67:225-230) I nferior wall acute myocardial infarction (AMI) is of- ten complicated by atrioventricular (AV) block. Be- fore the widespread use of thrombolytic therapy, complete AV block occurred in 8 to 13% of such pa- tients during the hospital course.1-3 Several investiga- tors report that larger infarctions are associatedwith AV block and that a high incidence of in-hospital com- plications and an increased short-term mortality rate occur among patients with complete AV block.1-3The long-term outcomeof hospital survivors, however,seems unaffected by the occurrence of complete AV block during hospitalization.1,4 One previous study suggested that completeAV block in patients with an inferior wall myocardial infarction is associated with coexistent mul- tivessel disease.5 The aforementioned studies were all conducted in the prethrombolytic era. The clinical im- plications of completeAV block in patients treated with reperfusion therapy have not been addressed. Whether the Occurrence of complete heart block is an indepen- dent risk factor for mortality has not been evaluated, becauseacute coronary anatomic and left ventricular function findings have not been available. We therefore undertook the present study to describe the clinical course and prognostic significance of complete AV block complicating inferior wall AM1 in patients treat- ed with reperfusion therapies. METHODS Patient population: The study population was culled from 810 consecutive patients who participated in 4 THE AMERICAN JOURNAL OF CARDIOLOGY FEBRUARY 1, 1991 225