Right bundle branch block: long-term prognosis in apparently healthy men

Area of Science:

• Cardiology
• Electrophysiology
• Gerontology

Background:

• Complete right bundle branch block (cRBBB) is a common electrocardiographic finding.
• Its long-term cardiac prognosis in asymptomatic individuals is not well-established.
• The Baltimore Longitudinal Study on Aging (BLSA) provides a unique population for studying aging-related cardiac conditions.

Purpose of the Study:

• To assess the long-term cardiac prognosis of clinically healthy men with cRBBB.
• To compare cardiac morbidity and mortality in men with cRBBB versus a matched control group.
• To investigate the association of cRBBB with cardiac risk factors, exercise tolerance, and conduction abnormalities.

Main Methods:

• Retrospective analysis of 24 men with cRBBB from the BLSA cohort (n=1,142).
• Follow-up period averaged 8.4 years.
• Comparison with an age-matched control group, assessing antecedent risk factors, clinical events, exercise capacity, and electrocardiographic parameters.

Main Results:

• No significant differences in coronary risk factors, obstructive lung disease, or major cardiac events (angina, myocardial infarction, heart failure, cardiac death) between groups.
• Maximal aerobic exercise tolerance and chronotropic response were similar in both groups.
• Significant increases in leftward axis deviation (46% vs 15%) and PR interval prolongation (29% vs 6%) were observed in the cRBBB group.

Conclusions:

• Complete right bundle branch block in asymptomatic men appears to be a manifestation of a primary conduction system abnormality.
• cRBBB in this cohort did not demonstrate an adverse effect on long-term cardiac morbidity or mortality.
• Further investigation into the electrophysiological significance of associated conduction abnormalities is warranted.