From the Guidelines
The workup of Right Bundle Branch Block (RBBB) should focus on identifying any underlying cardiac conditions while recognizing that RBBB can be a normal variant in healthy individuals, as per the 2018 ACC/AHA/HRS guideline on the evaluation and management of patients with bradycardia and cardiac conduction delay 1. Begin with a thorough history and physical examination, paying particular attention to symptoms like dyspnea, chest pain, syncope, or palpitations. Order an ECG to confirm RBBB, characterized by:
- QRS duration ≥120 ms
- rsr', rsR, rSR, or rarely a qR in leads V1 or V2
- S wave of greater duration than R wave or >40 ms in leads I and V6 in adults
- Normal R peak time in leads V5 and V6 but >50 ms in lead V1, as defined in the 2018 ACC/AHA/HRS guideline 1. Assess for other abnormalities, such as atrioventricular block or conduction tissue disease, using the definitions provided in the guideline 1. Laboratory tests should include electrolytes, renal function, and cardiac biomarkers if acute cardiac injury is suspected. Echocardiography is recommended to evaluate for structural heart disease, pulmonary hypertension, or right ventricular dysfunction. For patients with concerning symptoms or risk factors, consider additional testing such as stress testing to assess for coronary artery disease, ambulatory ECG monitoring for arrhythmias, or cardiac MRI for specific structural abnormalities. In asymptomatic patients with isolated RBBB and no evidence of structural heart disease, no specific treatment is typically required, but regular follow-up is advisable, as stated in the 2019 executive summary of the ACC/AHA/HRS guideline 1. The workup is important because RBBB may be associated with conditions like pulmonary embolism, congenital heart disease, cardiomyopathy, or myocardial infarction, though it can also be a benign finding in many individuals. It is essential to follow the most recent guidelines, such as the 2018 ACC/AHA/HRS guideline 1, to ensure accurate diagnosis and management of RBBB. The American Heart Association electrocardiography and arrhythmias committee, council on clinical cardiology, also provides recommendations for the standardization and interpretation of the electrocardiogram, including the diagnosis of RBBB 1. However, the 2018 ACC/AHA/HRS guideline 1 is the most recent and highest-quality study, and its recommendations should be prioritized.
From the Research
Working up RBBB
To work up a Right Bundle Branch Block (RBBB), consider the following steps:
- Evaluate the patient's medical history, including any underlying cardiac conditions or risk factors for cardiovascular disease 2, 3, 4
- Perform a physical examination to assess for any signs of cardiac dysfunction or other related conditions 4
- Obtain an electrocardiogram (ECG) to confirm the diagnosis of RBBB and evaluate for any other conduction abnormalities or signs of ischemia 3, 5, 4
- Consider further diagnostic testing, such as echocardiography or cardiac catheterization, to evaluate for any underlying cardiac conditions or to assess the need for interventions such as pacemaker implantation 3, 6
Diagnostic Considerations
When working up a patient with RBBB, consider the following diagnostic possibilities:
- Acute coronary syndromes (ACS), including myocardial infarction 3, 5
- Cardiac conduction system disease, including high-degree atrioventricular block 4, 6
- Cardiomyopathy or other structural heart diseases 4, 6
- Brugada syndrome, a familial arrhythmogenic cardiomyopathy 4
Management Strategies
The management of RBBB depends on the underlying cause and the presence of any related conditions. Consider the following strategies:
- Monitoring and surveillance for patients with asymptomatic RBBB and no underlying cardiac conditions 2, 4
- Medical therapy and interventions, such as pacemaker implantation, for patients with symptomatic RBBB or underlying cardiac conditions 3, 6
- Further evaluation and management for patients with suspected ACS or other related conditions 3, 5