Prevalence and clinical significance of electrocardiographic complete right bundle branch block in young individuals

Abstract Aims There is limited information on the clinical significance of complete right bundle branch block (CRBBB) in young individuals. The aim of this study was to determine the prevalence and significance of CRBBB in a large cohort of young individuals aged 14–35 years old. Methods and results From 2008 to 2018, 104,369 consecutive individuals underwent cardiovascular assessment with a health questionnaire, electrocardiogram, clinical consultation, and selective echocardiography. Follow-up was obtained via direct telephone consultations. Mean follow-up was 7.3 ± 2.7 years. CRBBB was identified in 154 (0.1%) individuals and was more prevalent in males compared with females (0.20 vs. 0.06%; P 0.05) and in athletes compared with non-athletes (0.25 vs. 0.14%; P 0.05). CRBBB-related cardiac conditions were identified in seven (5%) individuals (four with atrial septal defect, one with Brugada syndrome, one with progressive cardiac conduction disease, and one with atrial fibrillation). Pathology was more frequently identified in individuals with non-isolated CRBBB compared with individuals with isolated CRBBB (14 vs. 1%; P 0.05) and in individuals with a QRS duration of ≥130 ms compared with individuals with a QRS of 130 ms (10 vs. 1%; P 0.05). Conclusion The prevalence of CRBBB in young individuals was 0.1% and was more prevalent in males and in athletes. CRBBB-related conditions were identified in 5% of individuals and were more common in individuals with non-isolated CRBBB and more pronounced intraventricular conduction delay (QRS duration of ≥130 ms). Secondary evaluation should be considered for young individuals with CRBBB with symptoms, concerning family history, additional electrocardiographic anomalies, or significant QRS prolongation (≥130 ms).