Treatment of Right Bundle Branch Block
Isolated, asymptomatic right bundle branch block requires no treatment—observation only is recommended, as permanent pacing is explicitly contraindicated and may cause harm. 1
Initial Assessment and Risk Stratification
The management approach depends entirely on three critical factors: presence of symptoms (especially syncope), associated conduction abnormalities, and underlying cardiac disease. 1
Key evaluation steps:
Document symptoms carefully: Specifically assess for syncope, presyncope, dizziness, or exercise intolerance, as syncope predicts abnormal conduction properties and mandates further workup. 1, 2
Identify additional conduction abnormalities: Look for left anterior or posterior hemiblock (bifascicular block), first-degree AV block, or alternating bundle branch block patterns, as these combinations carry substantially higher risk for progression to complete heart block. 1, 2
Evaluate for structural heart disease: Obtain transthoracic echocardiography to assess for right ventricular enlargement, dysfunction, or other structural abnormalities, though RBBB is less commonly associated with structural disease than left bundle branch block. 1, 2
Screen for neuromuscular diseases: Evaluate for Kearns-Sayre syndrome, Anderson-Fabry disease, or Emery-Dreifuss muscular dystrophy, as these conditions may require permanent pacing with defibrillator capability. 1
Treatment Algorithm
Asymptomatic Isolated RBBB (No Other Abnormalities)
No treatment is indicated—observation only with regular follow-up. 1, 2 The American College of Cardiology explicitly contraindicates permanent pacing for isolated asymptomatic RBBB (Class III: Harm) due to lack of benefit and exposure to procedural risks and device complications. 1
Follow-up strategy: Regular ECG monitoring to detect progression to more complex conduction disorders. 1, 2
No cardiology referral needed: Asymptomatic patients with incidental RBBB discovered preoperatively without history of advanced heart block do not require referral, as progression to complete AV block perioperatively is rare. 1
Symptomatic RBBB (Syncope or Presyncope)
Urgent cardiology referral for electrophysiology study is mandatory. 1
Obtain ambulatory ECG monitoring: Use 24-hour to 14-day monitoring to establish symptom-rhythm correlation and document suspected higher-degree AV block. 1, 2
Proceed to electrophysiology study: Measure HV interval in patients with syncope where other testing is unrevealing. 1, 2
Permanent pacing indication (Class I): If syncope occurs with RBBB and electrophysiology study demonstrates HV interval ≥70 ms or evidence of infranodal block. 1, 2
RBBB with Additional Conduction Abnormalities
Alternating bundle branch block (RBBB alternating with LBBB):
- Permanent pacing is mandatory (Class I) due to high risk of sudden complete heart block. 1, 2 This indicates unstable conduction in both bundles and requires immediate intervention. 1
Bifascicular block (RBBB with left anterior or posterior hemiblock):
- Careful evaluation required: Consider electrophysiology study to evaluate atrioventricular conduction. 1, 2
- ECG screening of siblings recommended if bifascicular block is present in a young athlete. 2
RBBB with first-degree AV block:
- Requires careful monitoring for progressive cardiac conduction disease. 1
Acute Myocardial Infarction with New RBBB
New RBBB with first-degree AV block during acute MI:
- Transcutaneous pacing capability must be immediately available (Class I recommendation). 1, 2
- Temporary transvenous pacing may be considered (Class IIb). 1, 2
Special Populations
Neuromuscular diseases:
- Kearns-Sayre syndrome with conduction disorders: Permanent pacing is reasonable (Class IIa) with additional defibrillator capability if appropriate. 1, 2
- Anderson-Fabry disease with QRS >110 ms: Permanent pacing may be considered (Class IIb) with defibrillator capability if needed. 1, 2
Heart failure with RBBB:
- 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 demonstrated by speckle-tracking radial strain or interventricular mechanical delay may benefit. 3
- A long Q-LV time predicts good CRT response, even for patients with RBBB. 3
Advanced Imaging Considerations
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 cardiac MRI detects subclinical abnormalities in 33-42% of patients with conduction disease and normal echocardiograms. 2
Common Pitfalls to Avoid
Do not assume all RBBB patterns are benign: Always evaluate for underlying structural heart disease, especially when new-onset. 1
Avoid unnecessary permanent pacing: For isolated RBBB without symptoms or other conduction abnormalities, pacing causes harm without benefit. 1
Do not overlook progression risk: Patients with incomplete RBBB who progress to complete RBBB show higher incidence of heart failure and chronic kidney disease. 3
Recognize increased stroke risk: RBBB is independently associated with increased risk of ischemic stroke (adjusted HR 3.57), atrial fibrillation (adjusted HR 4.58), and all-cause mortality (adjusted HR 2.66), emphasizing the need for careful monitoring. 4