From the Guidelines
A new RBBB (Right Bundle Branch Block) typically means there is a newly detected blockage in the electrical conduction system of the heart, specifically in the right bundle branch, and requires prompt medical evaluation to assess for potential underlying heart conditions. Patients with a new RBBB should:
- Seek immediate medical attention, especially if accompanied by symptoms like chest pain, shortness of breath, or dizziness, as recommended by the American College of Emergency Physicians clinical policies subcommittee 1.
- Undergo a comprehensive cardiac evaluation, including:
- Electrocardiogram (ECG) to confirm the RBBB
- Echocardiogram to assess heart structure and function
- Blood tests to check for underlying conditions
- Possibly a stress test or cardiac catheterization, depending on other findings No specific medication is typically prescribed solely for RBBB, as treatment focuses on addressing any underlying heart conditions, according to the 2018 ACC/AHA/HRS guideline on the evaluation and management of patients with bradycardia and cardiac conduction delay 1. The right bundle branch is part of the heart's electrical system that coordinates contraction of the right ventricle, and when blocked, it can cause the right ventricle to contract slightly later than the left, potentially affecting heart efficiency, as noted in the 2021 ACC/AHA key data elements and definitions for heart failure 1. While some people with RBBB have no symptoms or complications, it can be a sign of underlying heart disease, which is why prompt evaluation is crucial.
From the Research
Definition and Implications of New Right Bundle Branch Block (RBBB)
- A new right bundle branch block (RBBB) is a significant finding on an electrocardiogram (ECG) that can indicate various cardiovascular conditions, including pulmonary embolism and acute coronary syndrome 2, 3, 4, 5, 6.
- The appearance of RBBB on an ECG can be a marker for obstruction of the main pulmonary trunk in patients with pulmonary embolism, with a correlation between the extent of obstruction and the appearance of RBBB 2.
- In patients with acute coronary syndrome, RBBB can be a sign of significant potential cardiovascular risk, identifying a subgroup of patients with high short- and long-term morbidity and mortality 5, 6.
Diagnostic and Therapeutic Implications
- The presence of RBBB in patients with suspected acute coronary syndromes can pose diagnostic challenges, and current guidelines consider RBBB in ACS patients as STEMI equivalent 6.
- However, recent studies suggest that further differentiation is necessary in this group, and RBBB patients without distinct STEMI signs in ECG may still show acute STEMI on angiography, indicating a potential benefit from immediate transfer to the cardiac catheterization laboratory 6.
- The occurrence of new RBBB following elective coronary artery bypass grafting (CABG) is indicative of perioperative myocardial necrosis and serves as a valuable tool for the diagnosis of new, perioperative ischemic events 4.
Prognostic Implications
- There is conflicting evidence regarding the prognostic implications of RBBB in the general population and in patients with heart diseases like acute coronary syndromes 6.
- However, recent studies indicate that both complete and incomplete RBBB are associated with increased cardiovascular morbidity and mortality, and RBBB patients often have poor outcomes compared to non-BBB and LBBB patients 6.