Management of Complete Right Bundle Branch Block (RBBB)

Initial Assessment

The American College of Cardiology defines complete RBBB by specific ECG criteria: QRS duration ≥120 ms, rSR' pattern in leads V1-V2, and S waves of greater duration than R waves in leads I and V6 1
Evaluate patients with RBBB for associated symptoms such as syncope, presyncope, dizziness, fatigue, or exercise intolerance, as recommended by the American College of Cardiology 2
Assess for underlying structural heart disease through cardiac imaging (echocardiography) to evaluate for right ventricular enlargement, dysfunction, or other structural abnormalities, as suggested by the American College of Cardiology 2
Determine if RBBB is isolated or associated with other conduction abnormalities (e.g., left anterior or posterior hemiblock, first-degree AV block), according to the American College of Cardiology 3

The American College of Cardiology recommends no specific treatment for asymptomatic patients with isolated RBBB, beyond regular observation and follow-up 4, 2
Regular follow-up with ECG monitoring is recommended to detect progression to more complex conduction disorders, as advised by the American College of Cardiology 4

Permanent pacing is indicated for patients with RBBB, syncope, and HV interval ≥70 ms on electrophysiologic study, according to the American College of Cardiology 5, 3
The American College of Cardiology recommends permanent pacing for alternating bundle branch block (QRS complexes with alternating LBBB and RBBB morphologies) due to high risk of developing complete atrioventricular block 5, 3
For RBBB with left anterior or posterior hemiblock (bifascicular block), careful evaluation for progressive cardiac conduction disease is required, as suggested by the American College of Cardiology 4
Consider electrophysiologic study to evaluate atrioventricular conduction in patients with RBBB and left anterior or posterior hemiblock, as recommended by the American College of Cardiology 3
ECG screening of siblings is recommended if bifascicular block is present in a young athlete, according to the European Heart Journal 6

In acute myocardial infarction with new RBBB and first-degree AV block, transcutaneous pacing capability should be available (Class I recommendation), as advised by the American College of Cardiology 4
Temporary transvenous pacing may be considered (Class IIb) in acute myocardial infarction with new RBBB and first-degree AV block, according to the American College of Cardiology 4
In patients with heart failure, mildly to moderately reduced LVEF (36%-50%), and LBBB (QRS ≥150 ms), cardiac resynchronization therapy may be considered, as suggested by the American College of Cardiology 3
Permanent pacing is reasonable for Kearns-Sayre syndrome with conduction disorders, according to the American College of Cardiology 3
Permanent pacing may be considered in Anderson-Fabry disease with QRS prolongation >110 ms, as recommended by the American College of Cardiology 3

The American College of Cardiology recommends confirming the diagnosis with 12-lead ECG demonstrating QRS duration ≥120 ms, rSR' pattern in leads V1-V2, and S waves of greater duration than R waves in leads I and V6 7
The American College of Cardiology suggests performing transthoracic echocardiography to assess for right ventricular enlargement, dysfunction, or other structural abnormalities, particularly in symptomatic patients or those with additional conduction abnormalities 8
Identifying any additional conduction abnormalities, including left anterior or posterior hemiblock (bifascicular block) or first-degree AV block, is crucial as these combinations carry higher risk for progression to complete heart block, according to the American College of Cardiology 7

The American College of Cardiology recommends obtaining ambulatory ECG monitoring (24-hour to 14-day duration) to establish symptom-rhythm correlation and detect intermittent higher-degree AV block in symptomatic patients 7, 8
Proceeding to electrophysiology study (EPS) in patients with syncope to measure the HV interval and assess for infranodal block is recommended by the American College of Cardiology 8
Permanent pacing is definitively recommended when syncope occurs with RBBB and EPS demonstrates HV interval ≥70 ms or evidence of infranodal block (Class I, Level C-LD), according to the American College of Cardiology 8

Obtaining cardiac MRI in selected patients when sarcoidosis, connective tissue disease, myocarditis, or other infiltrative cardiomyopathies are suspected clinically, even with normal echocardiography, is suggested by the American College of Cardiology, as studies show cardiac MRI detects subclinical abnormalities in 33-42% of patients with conduction disease and normal echocardiograms 8

The American College of Cardiology suggests documenting any history of palpitations or near-syncope episodes that may suggest intermittent higher-degree AV block in patients with complete RBBB 9
The American College of Cardiology recommends assessing for right ventricular enlargement, dysfunction, or other structural abnormalities using transthoracic echocardiography in patients with complete RBBB, as isolated RBBB is less commonly associated with structural disease 9

The American College of Cardiology recommends obtaining ambulatory ECG monitoring to establish symptom-rhythm correlation and detect intermittent higher-degree AV block in symptomatic patients with complete RBBB 9
The American College of Cardiology suggests proceeding to electrophysiology study to measure HV interval in patients with syncope where other testing is unrevealing 9

The American Heart Association recommends that patients with non-LBBB QRS morphology, including RBBB, may not derive significant benefit from cardiac resynchronization therapy (CRT), but those with left ventricular mechanical dyssynchrony may benefit 10
A long Q-LV time predicts good CRT response, even for patients with RBBB, emphasizing the importance of accurate tailoring of pacing therapy 10
Patients with RBBB demonstrating left ventricular mechanical dyssynchrony by speckle-tracking radial strain or interventricular mechanical delay may benefit from CRT 10