Thirty-year trends (1975-2005) in the magnitude and hospital death rates associated with complete heart block in patients with acute myocardial infarction: A population-based perspective

BACKGROUND: The contemporary magnitude and prognostic implications of complete heart block (CHB) in patients with acute myocardial infarction (AMI) are unknown. As part of a community-based study of patients hospitalized with AMI in the Worcester, MA, metropolitan area, changes over time in the incidence rates of CHB complicating AMI and the prognostic impact of CHB on short-term survival were examined. METHODS: The study population consisted of 13,663 residents of the Worcester metropolitan area who were hospitalized with AMI at all greater Worcester medical centers during 15 annual periods between 1975 and 2005. RESULTS: The average age of the hospitalized study sample was 69 years, and 58% were men. The overall proportion of patients with AMI who developed CHB was 4.1%. The incidence rates of CHB complicating AMI declined appreciably over time, with the greatest decline in these incidence rates occurring during the most recent years under study. In 2005, 2.0% of patients hospitalized with AMI developed CHB compared to 5.1% in the initial study year of 1975. Patients with AMI who developed CHB had higher inhospital death rates (43.2%) than did those who did not develop CHB (13.0%) (P < .001). The hospital death rates associated with CHB declined appreciably over time, particularly during the most recent years under study. Several patient characteristics were associated with an increased risk for developing CHB during hospitalization for myocardial infarcation. CONCLUSIONS: Our findings indicate recent encouraging declines in the incidence rates of CHB complicating AMI and improving trends in the hospital prognosis of these patients.