Treatment and outcomes of left bundle-branch block patients with myocardial infarction who present without chest pain

OBJECTIVES We sought to determine the importance of chest pain on presentat ion as a predictor of in-hospital treatment and mortality in myocardial inf arction (MI) patients with left bundle-branch block (LBBB). BACKGROUND Left bundle-branch block patients have a high mortality after MI but are unlikely to receive reperfusion therapy despite evidence from clin ical trials demonstrating the efficacy of thrombolytic therapy. Nearly half of MI patients with LBBB present without chest pain. METHODS We studied the clinical features, treatment and in-hospital surviva l of 29,585 patients with LBBB enrolled in the National Registry of MI 2 (J une 1994 through March 1998). Multivariate logistic regression was used to assess the independent effect of chest pain on reperfusion decisions and in -hospital mortality. RESUTLS Left bundle-branch block patients with chest pain were greater than five-fold more likely to receive reperfusion therapy (13.6% vs. 2.6%) than LBBB patients without chest pain; they were also more likely to receive as pirin, beta-adrenergic blocking agents, heparin and nitrates (all p < 0.000 1). Unadjusted in-hospital mortality was 18% in patients with chest pain an d 27% in patients without chest pain. Adjusting for patient characteristics reduced the odds ratio associated with the absence of chest pain from 1.47 (95% confidence interval: 1.41 to 1.53) to 1.21 (95%, confidence interval: 1.12 to 1.30). The remainder of the mortality difference was caused by the undertreatment of patients without chest pain, particularly the low utiliz ation of aspirin and beta-blockers. CONCLUSIONS Left bundle-branch block patients with MI who present without c hest pain are less likely to receive optimal therapy and are at increased r isk of death. Prompt recognition and treatment of this high-risk subgroup s hould improve survival. (C) 2000 by the American College of Cardiology.