What are the causes and management of Right Bundle Branch Block (RBBB)?

From the Guidelines

Right Bundle Branch Block (RBBB) is primarily caused by conditions such as coronary artery disease, myocardial infarction, cardiomyopathy, and congenital heart defects, and its management should focus on treating the underlying condition rather than the conduction abnormality itself, as stated in the 2018 ACC/AHA/HRS guideline on the evaluation and management of patients with bradycardia and cardiac conduction delay 1. The main causes of RBBB can be categorized into several groups, including:

• Coronary artery disease and myocardial infarction, which can damage the heart's conduction system
• Cardiomyopathy, which can affect the heart's structure and function
• Congenital heart defects, which can affect the heart's development and function
• Pulmonary embolism, which can put strain on the right side of the heart
• Myocarditis, which can cause inflammation of the heart muscle
• Cardiac surgery, which can cause damage to the heart's conduction system
• Aging-related degenerative changes, which can affect the heart's conduction system over time In terms of management, patients with RBBB should undergo evaluation for underlying structural heart disease, including echocardiography and possibly stress testing, especially if there are risk factors for coronary artery disease, as recommended in the 2018 ACC/AHA/HRS guideline 1. For isolated, asymptomatic RBBB in individuals with no structural heart disease, no specific treatment is typically required, and regular cardiac follow-up with electrocardiograms may be recommended to monitor for progression 1. However, when RBBB is associated with underlying heart or lung disease, treatment should focus on addressing the primary condition rather than the conduction abnormality itself, such as treating coronary artery disease with medications like aspirin, statins, beta-blockers, or revascularization procedures 1. Additionally, pacemaker implantation may be necessary if RBBB is part of a more extensive conduction system disease causing symptomatic bradycardia or heart block, with the decision for pacemaker therapy based on symptoms and the presence of other conduction abnormalities, not solely on the RBBB finding 1.

From the Research

Causes of RBBB

• Coronary artery disease (CAD) is a common cause of Right Bundle Branch Block (RBBB), as seen in patients with RBBB and CAD 2
• The presence of RBBB in patients with CAD may indicate more severe and extensive left ventricular myocardial damage, as well as more severe CAD 2
• Male sex and age are associated with an increased risk of developing complete RBBB (cRBBB) 3
• Right bundle branch block is not a predictor of coronary artery disease, and its presence does not necessarily indicate a higher severity of CAD 4
• Other potential causes of RBBB include pulmonary embolism, which can cause acute right ventricular overload and lead to the appearance of RBBB on an electrocardiogram (ECG) 5

Management of RBBB

• Patients with RBBB should undergo further evaluation to determine the underlying cause of the condition, including stress echocardiography and coronary arteriography 2, 6
• The presence of RBBB in patients with suspected CAD should prompt further investigation, including angiographic studies to assess the severity of CAD 4
• Patients with cRBBB should be monitored closely for signs of cardiovascular morbidity and mortality, as they may be at increased risk for adverse outcomes 3
• The appearance of RBBB on an ECG in patients with pulmonary embolism may indicate massive obstruction of the main pulmonary trunk and should prompt immediate medical attention 5