Clinical characteristics and the severity of coronary atherosclerosis of different subtypes of bundle‐branch block

BACKGROUND: Right bundle‐branch block (RBBB) and left bundle‐branch block (LBBB) play a role in the pathogenesis and progression of coronary artery disease (CAD). However, the clinical features and the severity of coronary artery disease associated with different subtypes of bundle‐branch block, according to time of new appearance, is not well characterized in patients with no known CAD. METHODS: We retrospectively analyzed data pertaining to consecutive patients with RBBB or LBBB who underwent coronary angiography. The severity of coronary lesions was evaluated using the SYNTAX score. The differential effect of new‐onset RBBB, old RBBB, new‐onset LBBB, and old LBBB on the severity of CAD and its association with clinical characteristics was quantified. Multivariate logistic regression analysis was performed to evaluate the effect of RBBB and LBBB on the degree of coronary atherosclerosis in patients without known CAD. RESULTS: Out of the 243 patients, 72 patients had old LBBB, 37 had new‐onset LBBB, 93 patients had old RBBB, and 41 patients had new‐onset RBBB. On univariate analysis, age, systolic blood pressure, diastolic blood pressure, creatinine, serum glucose, and glycosylated hemoglobin level were associated with high SYNTAX score (p < .05 for all). Patients in the new‐onset RBBB, old RBBB, new‐onset LBBB, and old LBBB groups showed significant differences in baseline characteristics and coronary atherosclerosis (p < .05 for all). However, there were no significant between‐group differences with respect to the degree of coronary atherosclerosis as assessed by SYNTAX score. CONCLUSIONS: New‐onset RBBB, old RBBB, new‐onset LBBB, and old LBBB were not associated with the severity of coronary lesions as assessed by SYNTAX score in patients without known CAD.