From the Guidelines
Sinus bradycardia with right bundle branch block (RBBB) does not typically require specific treatment in asymptomatic patients, but symptoms such as dizziness, fatigue, or syncope warrant further evaluation and potential treatment with discontinuation of rate-slowing medications, atropine, or pacemaker implantation. The presence of RBBB should prompt evaluation for underlying structural heart disease, pulmonary hypertension, or congenital heart defects 1. According to the 2018 ACC/AHA/HRS guideline on the evaluation and management of patients with bradycardia and cardiac conduction delay, there is no established minimum heart rate or pause duration where permanent pacing is recommended, and establishing temporal correlation between symptoms and bradycardia is important when determining whether permanent pacing is needed 1. Some key points to consider in the management of sinus bradycardia with RBBB include:
- Asymptomatic patients with mild bradycardia (>50 bpm) and incidental RBBB do not require specific treatment 1
- Symptomatic patients may require treatment with discontinuation of rate-slowing medications, atropine, or pacemaker implantation 1
- RBBB should prompt evaluation for underlying structural heart disease, pulmonary hypertension, or congenital heart defects 1
- Regular cardiac follow-up is recommended, with frequency determined by symptom severity and the presence of other cardiac conditions 1
From the Research
Sinus Bradycardia with Right Bundle Branch Block
- Sinus bradycardia is a condition characterized by a slow heart rate, typically less than 60 beats per minute, originating from the sinoatrial node 2.
- Right bundle branch block (RBBB) is an abnormality of the electrical conduction system of the heart, where the right bundle branch is blocked, leading to an abnormal QRS complex on the electrocardiogram (ECG) 2.
- The combination of sinus bradycardia and RBBB can lead to various clinical presentations, including syncope, which is a transient loss of consciousness due to inadequate cerebral blood flow 2.
- A study published in the European Heart Journal in 2011 found that patients with syncope and bundle branch block, including RBBB, are at high risk of developing atrio-ventricular block, but syncope may also be due to other aetiologies 2.
- The study used a systematic diagnostic approach, including initial evaluation, electrophysiological study, and insertion of an implantable loop recorder, to establish an aetiological diagnosis in 82.7% of patients with syncope and bundle branch block 2.
- The most common aetiology of syncope in patients with bundle branch block was found to be bradyarrhythmia, which includes sinus bradycardia 2.