From the Guidelines
Right bundle branch block (RBBB) is a cardiac conduction abnormality that typically requires no specific treatment when found in isolation without other cardiac issues. RBBB is diagnosed on an electrocardiogram (ECG) by characteristic findings including a widened QRS complex (greater than 120 milliseconds), an RSR' pattern in lead V1 (sometimes called "rabbit ears"), and wide S waves in leads I and V6. The condition occurs when damage or disease affects the right bundle branch, causing the right ventricle to depolarize later than the left ventricle. While isolated RBBB is often benign, especially in healthy individuals, it may indicate underlying heart disease in some cases, such as coronary artery disease, cardiomyopathy, or congenital heart defects.
Key Considerations
- Patients with newly discovered RBBB should undergo evaluation for potential underlying cardiac conditions, including echocardiography and possibly stress testing, as recommended by the 2018 ACC/AHA/HRS guideline on the evaluation and management of patients with bradycardia and cardiac conduction delay 1.
- No medications are specifically prescribed for RBBB itself, but treatment focuses on any underlying heart conditions if present.
- Regular cardiac follow-up is recommended, particularly if the patient develops symptoms like shortness of breath, chest pain, or syncope.
- In patients with syncope and RBBB, an electrophysiological study (EPS) can be used to evaluate atrioventricular conduction and identify the presence and extent of infranodal disease, as suggested by the 2018 ACC/AHA/HRS guideline 1.
- Permanent pacing has been recommended for patients with syncope and HV intervals ≥70 ms or frank infranodal block, as stated in the 2018 ACC/AHA/HRS guideline 1.
Management and Treatment
- The management of RBBB is primarily focused on treating any underlying heart conditions that may be present.
- Patients with RBBB and symptoms such as syncope or shortness of breath should be evaluated for potential underlying cardiac conditions and treated accordingly.
- The use of electrophysiological studies and permanent pacing should be considered in patients with RBBB and syncope, as recommended by the guidelines 1.
From the Research
Right Bundle Branch Block Overview
- Right bundle branch block (RBBB) is a condition where the right bundle branch of the heart's electrical conduction system is blocked, causing the heart's ventricles to contract unevenly 2, 3.
- The electrocardiographic (ECG) appearances of RBBB include prolongation of the QRS complex, RR' or rR' appearances in V1, and widened S waves in leads exploring the left ventricle 3.
Prognostic Features and Associations
- RBBB has been associated with an increased risk of sudden cardiac arrest (SCA) due to pulmonary embolism, particularly in patients with a QR pattern in V1 on ECG 2.
- The presence of RBBB and SIQIII-type patterns on ECG has been linked to right ventricular dysfunction (RVD) and cardiac injury in patients with acute pulmonary embolism 4.
- However, some studies suggest that RBBB is not a predictor of coronary artery disease (CAD) and does not have a significant association with the presence and severity of CAD 5, 6.
Clinical Implications
- The presence of RBBB with a QR pattern in V1 on ECG may be an independent predictor for high-risk pulmonary embolism patients who require advanced treatments, including systemic thrombolysis or invasive embolectomy 2.
- RBBB and SIQIII-type patterns may be useful for risk stratification in acute pulmonary embolism, as they are associated with RVD and cardiac injury 4.
- Further research is needed to explore the prioritization of thrombolysis for high-risk pulmonary embolism patients before confirmation with computed tomographic pulmonary angiogram (CTPA), when ECG findings strongly suggest the diagnosis 2.