Abstract 3620: Right Bundle Branch Block is associated with a high 15 year Mortality Rate in patients presenting with Chest Pain consistent with Unstable Angina - The Olmsted County Chest Pain Study
Background: The long-term outcomes of patients with bundle branch block (BBB) and acute chest pain (ACP) are not well established.
Methods: We retrospectively identified all residents of Olmsted County, Minnesota presenting to one of the county’s 3 emergency rooms with ACP from January 1, 1985 through December 31, 1992.The complete medical records of the screened population were abstracted from the Rochester Epidemiology Project and the Olmsted County Health Care Utilization and Expenditures Database and reviewed by an experienced nurse abstractor. Dates of death were obtained through the State of Minnesota Electronic death certificates, State of Minnesota death tapes, Olmsted County electronic death certificates and Mayo clinic records. Cox models were used to estimate the adjusted association between BBB and mortality.
Results: Of the 6,801 residents of Olmsted County who presented to an ER with ACP, 2,234 (32.8%) had symptoms consistent with unstable angina (mean age 64 yrs, 58% male).Right BBB (RBBB) was present in 4.0%, left BBB (LBBB) in 4.5%. We observed 1208 deaths over a median follow-up time of 16.6 years. Survival curves are shown in the Figure⇓. After adjusting for other risk factors, LBBB at presentation portended a 1.79 fold (95% CI 1.49 –2.15, p<0.001) increase in mortality while RBBB led to a 1.25 fold higher risk (95% CI 1.04 –1.50, p =0.018).
Conclusions: While the adverse effect of LBBB on ACP patients is well known, this study demonstrates increased long term mortality associated with presence of RBBB, which has historically been considered a relatively benign entity.