Cardiovascular outcomes in patients with intraventricular conduction blocks: A sixteen-year follow-up in a state-wide database

Background To assess the adverse clinical effects of left anterior hemiblock alone or in combination with right bundle branch block and of complete left bundle branch block in comparison with isolated right bundle branch block and the relationship of these effects with altered mechanoelectric factors resulting in left ventricular dysfunction. Methods In a 16-year follow-up study using a statewide database, we studied the occurrence of mortal and morbid cardiovascular (CV) events among patients without apparent ischemic heart disease who had left anterior hemiblock (LAHB, n=4273, right bundle branch block (RBBB) with LAHB (BFBB, n=1857) and left bundle branch block (LBBB, n=9484 compared to isolated RBBB (n=25288). Results After adjustment for demographics, co-morbidities and insurance, LAHB was associated with a significant excess risk of all-cause death (HR 1.134, 95% CI 1.061-1.213, p=0.0002) and CV death (HR 1.329, 95% CI 1.174-1.501, p<0.0001). BFBB was associated with excess HF (HR 1.190, 95% CI 1.048-1.351, p<0.0071), all-cause death (HR 1.440, 95% CI 1.045-1.252, p=0.0036) and CV death (HR 1.210, 95% CI 1.020-1.436, p<0.0001). LBBB was associated with an excess risk of MR (HR 1.307, 95% CI 1.116-1.530, p<0.0009), HF 1.177, 95% CI1.097-1.263, p<0.0001) and CV death (HR 1.220, 95% CI 1.106-1.345, p<0.0001). Conclusions In patients without apparent ischemic heart disease, the presence of LAHB alone or in combination with RBBB imparts increased risk of CV and all-cause death compared to isolated RBBB. BFBB is also associated with an increased risk of HF.