Treatment of Right Bundle Branch Block (RBBB)

Initial Assessment and Risk Stratification

The American College of Cardiology recommends determining symptom status and associated conduction abnormalities in patients with RBBB, including obtaining a 12-lead ECG to confirm RBBB and identify additional conduction disorders, with a QRS ≥120 ms, rSR' pattern in V1-V2, and S waves greater than R waves in leads I and V6 1, 3
Assessment should specifically include evaluation for syncope, presyncope, lightheadedness, dizziness, fatigue, or exercise intolerance in patients with RBBB 1, 3
Transthoracic echocardiography is recommended if structural heart disease is suspected, particularly in symptomatic patients, according to the American College of Cardiology 4, 1
RBBB is less commonly associated with structural disease compared to LBBB, with a lower incidence of underlying heart conditions 4, 2

The American College of Cardiology states that asymptomatic isolated RBBB requires no treatment, with observation only recommended, as permanent pacing is contraindicated and may cause harm, classified as a Class III (Harm) recommendation 1, 2
Regular follow-up with ECG monitoring is recommended to detect progression to more complex conduction disorders in patients with asymptomatic isolated RBBB 1, 2
For patients with syncope, ambulatory ECG monitoring (24-hour to 14-day duration) should be obtained to establish symptom-rhythm correlation and detect intermittent higher-degree AV block, as recommended by the American College of Cardiology 4, 1, 3
Permanent pacing is definitively indicated (Class I) if electrophysiology study demonstrates HV interval ≥70 ms or evidence of infranodal block, according to the American College of Cardiology 1, 3, 2

In cases of acute myocardial infarction with new RBBB and first-degree AV block, transcutaneous pacing capability should be available (Class I recommendation), and temporary transvenous pacing may be considered (Class IIb), as recommended by the American College of Cardiology 3, 2
For patients with neuromuscular diseases, such as Kearns-Sayre syndrome, permanent pacing is reasonable (Class IIa), and may be considered (Class IIb) for Anderson-Fabry disease with QRS >110 ms, according to the American College of Cardiology 3, 2
In heart failure with RBBB, patients with non-LBBB QRS morphology may not derive significant benefit from cardiac resynchronization therapy (CRT), but those demonstrating left ventricular mechanical dyssynchrony by speckle-tracking radial strain or interventricular mechanical delay may benefit from CRT, as stated by the American College of Cardiology 3

Cardiac MRI should be obtained in selected patients when sarcoidosis, connective tissue disease, myocarditis, or other infiltrative cardiomyopathies are suspected clinically, even with normal echocardiography, as recommended by the American College of Cardiology 3
Studies show cardiac MRI detects subclinical abnormalities in 33-42% of patients with conduction disease and normal echocardiograms, highlighting its importance in diagnostic evaluation 3