From the Guidelines
Right Bundle Branch Block (RBBB) is a cardiac conduction abnormality that typically doesn't require specific treatment when found incidentally in otherwise healthy individuals, and management should focus on identifying and treating any underlying heart conditions rather than the RBBB itself 1.
Definition and Diagnosis
RBBB is characterized by a delay or block in the electrical impulses traveling through the right bundle branch, causing the right ventricle to activate after the left ventricle. It is diagnosed on an electrocardiogram (ECG) by a widened QRS complex (greater than 120 milliseconds) with a characteristic RSR' pattern in lead V1 and wide S waves in leads I and V6.
Treatment Approach
No medications or interventions are needed for isolated RBBB without symptoms or underlying heart disease. However, when RBBB is discovered, a thorough cardiac evaluation is recommended to identify any underlying heart conditions that might have caused it, such as coronary artery disease, cardiomyopathy, or congenital heart defects. This evaluation may include an echocardiogram, stress test, or other cardiac imaging.
- The evaluation should prioritize identifying conditions that could impact morbidity, mortality, and quality of life.
- Treatment will focus on the underlying condition rather than the RBBB itself, as evidenced by guidelines from the American College of Cardiology/American Heart Association Task Force on Clinical Practice Guidelines 1.
- In rare cases where RBBB contributes to severe conduction problems causing very slow heart rates, a pacemaker might be necessary, emphasizing the importance of individualized treatment based on the patient's specific condition and symptoms.
Considerations for Cardiac Resynchronization Therapy (CRT)
For patients with RBBB, the benefit of CRT is not well established, and current evidence suggests that it may not provide significant benefits for this subgroup 1. However, some studies indicate that certain patients with RBBB and evidence of left ventricular mechanical dyssynchrony might benefit from CRT, highlighting the need for personalized assessment and treatment planning.
- The decision to use CRT in patients with RBBB should be based on a comprehensive evaluation of the patient's condition, including the presence of left ventricular mechanical dyssynchrony and other factors that could influence the effectiveness of CRT.
- Ongoing research, such as the Pacing Affects Cardiovascular Endpoints in Patients With Right Bundle-Branch Block (PACE-RBBB) trial, aims to provide more insight into the potential benefits of CRT for patients with RBBB, but as of the latest guidelines, the approach remains cautious and individualized 1.
From the Research
Definition and Treatment of RBBB
- RBBB (Right Bundle Branch Block) is a pattern seen on the 12-lead ECG, resulting from interrupted normal electrical activity in the His-Purkinje system 2.
- The normal sequence of activation is altered in RBBB, with a resultant characteristic appearance on the ECG manifest by a widened QRS complex and changes in the directional vectors of the R and S waves 2.
- Treatment of RBBB depends on the underlying cause and symptoms, but calcium channel blockers have been shown to be effective in converting RBBB to sinus rhythm in patients without underlying ischemic heart disease 3.
Diagnosis and Prognosis
- RBBB can be diagnosed using a 12-lead ECG, which shows a widened QRS complex and changes in the directional vectors of the R and S waves 2.
- The prognosis of RBBB is generally considered benign, but recent studies suggest that both complete and incomplete RBBB are associated with increased cardiovascular morbidity and mortality 4.
- In patients with suspected acute coronary syndromes, RBBB is considered a STEMI equivalent and requires immediate invasive evaluation 4.
Treatment Options
- Calcium channel blockers, such as verapamil or diltiazem, have been shown to be effective in converting RBBB to sinus rhythm in patients without underlying ischemic heart disease 3.
- Other treatment options, such as adenosine or amiodarone, may also be used, but the success rate is lower compared to calcium channel blockers 3.
- In patients with acute myocardial infarction, new onset RBBB should be considered a standard indicator for reperfusion therapy, as it is associated with more severe symptoms and higher incidents of complete occlusion of the infarct-related artery 5.