Bundle branch block and pacemaker Rhythm as independent predictors of mortality in critically ill cardiac patients

Introduction: Bundle branch block (BBB) it is often associated with underlying heart conditions, but little is known about prognosis of patients admitted to intensive cardiovascular care unit and BBB on ECG, especially right BBB (RBBB). Aim: The aim of the current study was to investigate the prognostic value of BBB [left BBB (LBBB), RBBB] at admission to a tertiary care center intensive cardiovascular care unit (ICCU). Methods: We analyzed all ECG's on admissions to ICCU from July 2019 through December 2021 and follow them for up to 4 years in order to examine the long term prognosis of preexisting BBB at admission. Results: The study included 2552 patients (30.3 % female; mean age 67 ± 15.4 years). Over 4 years, mortality was higher in patients with LBBB or RBBB compared with those without BBB (42 % and 47 % vs. 21 %, p = 0.0001). Pacemaker rhythm was associated with the highest mortality (54 %). In multivariable analysis, RBBB and pacemaker rhythm independently predicted poor prognosis. Moreover, among patients with acute coronary syndrome, RBBB was the only independent predictor. Conclusion: The presence of preexisting BBB at the time of admission to ICCU, irrespective of the cause of hospitalization, is associated with an unfavorable 4-year prognosis.