Frequency of New-Onset Right Bundle Branch Block among Patients Presenting with Anterior Wall Myocardial Infarction at a Tertiary Care Cardiac Center

Abstract

Objective: To determine the frequency of new-onset right bundle branch block (RBBB) among patients presenting with anterior wall myocardial infarction (AWMI). Methodology: A descriptive cross-sectional study was conducted in the Department of Cardiology, Punjab Institute of Cardiology, Lahore, from October 2025 to March 2026. A total of 100 consecutive patients aged 30–80 years with confirmed anterior wall myocardial infarction were enrolled using non-probability consecutive sampling. The sample size was calculated using a 95% confidence level, a 5% margin of error, and an anticipated prevalence of new-onset RBBB of 6.3% based on previous literature. New-onset RBBB was diagnosed using standard electrocardiographic criteria in patients without a documented history of RBBB. Demographic and clinical characteristics were recorded using a structured proforma. Results: The mean age of the participants was 45.12 ± 13.57 years, and the mean body mass index was 28.79 ± 5.69 kg/m². Among the 100 enrolled patients, 67% were male, and 64% had diabetes mellitus. New-onset right bundle branch block was identified in 17% of patients presenting with anterior wall myocardial infarction. No statistically significant associations were observed between new-onset RBBB and age group (p = 0.826), gender (p = 0.431), or diabetes mellitus (p = 0.626). Conclusion: New-onset right bundle branch block was observed in approximately one-sixth of patients presenting with anterior wall myocardial infarction. Although no significant associations were identified with age, gender, or diabetes mellitus, early recognition of this conduction abnormality remains clinically important because it may facilitate prompt diagnosis and appropriate management. Larger prospective multicenter studies are warranted to validate these findings and evaluate the prognostic implications of new-onset RBBB.