From the Guidelines
Patients with Right Bundle Branch Block (RBBB) should undergo a baseline cardiac evaluation to rule out underlying structural heart disease, as the presence of RBBB on ECG increases the risk of left ventricular systolic dysfunction, although the yield is lower than in patients with Left Bundle Branch Block (LBBB) 1.
Diagnosis and Evaluation
RBBB is diagnosed on an electrocardiogram (ECG) by a QRS complex duration of ≥120 milliseconds, with a characteristic RSR' pattern (rabbit ears) in the right precordial leads (V1-V3) and wide S waves in leads I and V6. The condition may be found incidentally in healthy individuals or can occur secondary to underlying heart disease such as coronary artery disease, cardiomyopathy, congenital heart defects, or pulmonary conditions.
Clinical Significance
The significance of RBBB depends on the clinical context - in asymptomatic individuals without heart disease, it generally has a benign prognosis, while in those with cardiac conditions, it may indicate more extensive disease and potentially worse outcomes.
- In patients with RBBB or intraventricular conduction delay on ECG, there is an increased risk of left ventricular systolic dysfunction compared with those with completely normal ECGs 1.
- Electrocardiography is the primary method of diagnosing potential conduction disorders, and ambulatory electrocardiographic monitoring can be used to document clinically significant arrhythmias in asymptomatic patients 1.
Management
In isolated RBBB without symptoms or other cardiac abnormalities, no specific treatment is required. However, regular cardiac follow-up is recommended, especially if other cardiac abnormalities are present.
- An echocardiogram may be useful in patients with suspected structural heart disease, as it can uncover treatable disease or impact management decisions such as cardiac resynchronization device placement 1.
- An electrophysiological study (EPS) may provide acute diagnostic information and can help identify patients at higher risk for complete heart block, but it has variable sensitivity and imparts a small procedural risk 1.
From the Research
Definition and Prevalence of RBBB
- Right bundle-branch block (RBBB) occurs in 0.2% to 1.3% of people and is considered a benign finding 2
- However, some studies have suggested increased risk of cardiovascular morbidity and mortality associated with RBBB 2, 3
Association with Cardiovascular Disease
- RBBB was predictive of all-cause and cardiovascular-related mortality after adjusting for age, sex, diabetes mellitus, hypertension, obesity, current and past history of smoking, and use of a heart rate-lowering drug 2
- Patients with RBBB exhibited more hypertension, decreased functional aerobic capacity, slower heart rate recovery, and more dyspnea on exercise testing 2
- RBBB may be a marker of early cardiovascular disease (CVD) and merit further prospective evaluation 2
Diagnostic Value
- Dobutamine stress echocardiography (DSE) is a sensitive, specific, and accurate non-invasive test for identifying coronary artery disease (CAD) in patients with left bundle branch blockage (LBBB) 4
- However, the diagnostic value of RBBB for CAD is not well established, and further studies are needed to determine its clinical significance 4, 5
Prognostic Implications
- RBBB is associated with increased risk of mortality in patients with suspected myocardial infarction, but the likelihood of myocardial infarction is equally frequent in patients without bundle branch block 3
- Procedural RBBB during alcohol septal ablation for hypertrophic obstructive cardiomyopathy is not associated with adverse clinical outcomes and may be associated with reduction in repeat procedures 6