The prognostic significance of intermediate QRS prolongation in acute myocardial infarction

Complete right and left bundle branch block and advanced atrioventricular b lock present on admission electrocardiograms of patients with acute myocard ial infarction, are associated with pour short and long-term outcome. Littl e is known about the impact of intermediate QRS prolongation (0.09-0.11 s) on the prognosis of acute myocardial infarction. In this study, among 1100 consecutive patients with acute myocardial infarction treated with thrombol ysis, the QRS duration on admission electrocardiogram was <0.09 s in 536 (4 8%) patients, between 0.09 and 0.11 s in 496 (45%) patients and >0.11 s in 78 (7%) patients. QRS duration was strongly associated with 7-day (0.6%, 6% , 18%, P <0.001), 30-day (1%, 8%, 22%, P <0.001) and 1-year (3%, 11%, 26%, P <0.001) all-cause mortality. After adjustment for significant variables a ssociated with 1-year mortality, including age, female gender, diabetes mel litus, systemic hypertension, previous myocardial infarction, anterior myoc ardial infarction and Killip class greater than or equal to2 on admission, both levels of QRS prolongation remained significant independent predictors of short and long-term all-cause mortality. (C) 2001 Elsevier Science Irel and Ltd. All rights reserved.