Incomplete Right Bundle Branch Block: A Narrative Review of Clinical Relevance, Diagnostic Pitfalls, and Prognostic Implications.

INTRODUCTION

Incomplete right bundle branch block (iRBBB) is a frequent electrocardiographic (ECG) finding, often considered benign. However, recent evidence suggests it may be associated with underlying structural or electrical abnormalities, particularly in selected populations.

METHODS

We conducted a narrative review of population-based cohorts, mechanistic studies, and clinical trials focused on the prevalence, pathophysiological mechanisms, differential diagnosis, and prognostic implications of iRBBB.

RESULTS

iRBBB is common in athletes and individuals with pulmonary or structural heart diseases. Although frequently asymptomatic, it may reflect right ventricular strain, pulmonary hypertension, or a predisposition to arrhythmias such as atrial fibrillation. Specific ECG features, comorbidities, and clinical context help to differentiate benign from pathologic iRBBB.

CONCLUSIONS

iRBBB should not be routinely regarded as a harmless variant. In high-risk individuals, it may carry clinical and prognostic significance, warranting further evaluation. Standardized criteria and additional prospective studies are needed to better understand its implications. Infographic available for this article. INFOGRAPHIC.