Bundle branch block in acute Q wave inferior wall myocardial infarction. A high risk subgroup of inferior myocardial infarction patients. The SPRINT Study Group. Secondary Prevention Reinfarction Israeli Nifedipine Trial.

The aim of this study was to determine the incidence and impact of right and left bundle branch block on the in-hospital, 5-year and 10-year mortality of patients with acute inferior Q wave myocardial infarction. A retrospective analysis of clinical characteristics, hospital, 1-, 5-, and 10-year mortality of 2215 consecutive patients with acute inferior Q wave myocardial infarction hospitalized in 13 coronary care units in Israel was performed. Bundle branch block during acute Q wave inferior wall myocardial infarction was present in 108 patients (4.9%), 85 of whom had right and 23 left bundle branch block. Patients with bundle branch block had more in-hospital complications than those without, irrespective of the site and time of appearance of the block. In addition, atrial fibrillation (19%), complete atrioventricular block (21%) and congestive heart failure (45%) appeared more frequently in patients with, than in those without, bundle branch block (11%, 9% and 31%, respectively), and in-hospital and 5-year mortality were higher in patients with the block (22%, 33%) than in those without it (13% and 23%, respectively). Bundle branch block emerged as an independent predictor of death only among patients with new right bundle branch block, and right bundle branch block emerged as an independent predictor for the development of complete atrioventricular block (odds ratio 2.13; 90% confidence interval 1.39-3.28). However, hospital mortality among patients with inferior myocardial infarction and complete atrioventricular block was virtually independent of bundle branch block (39% with vs 36% without bundle branch block, respectively).(ABSTRACT TRUNCATED AT 250 WORDS)