Right Bundle Branch Block (RBBB) on ECG: Causes, Diagnosis, and Treatment

Introduction

Right Bundle Branch Block (RBBB) is a condition where the electrical impulses in the heart are delayed or blocked in the right bundle branch, which affects the right ventricle’s ability to contract properly.

Causes of RBBB

RBBB can be caused by a variety of factors, including: - Congenital heart defects (e.g., atrial septal defect) - Ischemic heart disease (resulting from coronary artery disease or myocardial infarction) - Cardiomyopathies (dilated or hypertrophic) - Pulmonary diseases (like pulmonary embolism or chronic obstructive pulmonary disease) - Hypertension and left ventricular hypertrophy - Idiopathic causes (sometimes seen in healthy individuals without heart disease)

ECG Characteristics of RBBB

An ECG with RBBB typically shows: - QRS complex duration ≥120 ms (wide QRS) - rsR’ pattern in leads V1-V2 (a “M”-shaped appearance) - Broad S wave in leads I, aVL, and V6

Is RBBB Dangerous?

• Isolated RBBB (without underlying heart disease) is usually benign.
• New-onset RBBB in the presence of symptoms like chest pain or dyspnea requires further investigation for conditions like ischemia or pulmonary embolism.

Treatment of RBBB

• No treatment needed for asymptomatic individuals with isolated RBBB.
• Identify and treat underlying conditions : If RBBB is due to myocardial infarction, pulmonary embolism, or cardiomyopathy, the primary disease should be managed accordingly.
• Pacemaker therapy : If RBBB is associated with more significant conduction abnormalities (e.g., high-degree atrioventricular block), a pacemaker may be indicated.

Conclusion

RBBB often does not require treatment unless symptoms or underlying pathology warrant further management. If detected on ECG, a detailed evaluation is necessary to rule out associated conditions.

Source recommendations

1. American College of Cardiology/American Heart Association Guidelines for the Management of Patients with Supraventricular Arrhythmias

1. https://www.ahajournals.org/doi/10.1161/cir.0000000000000311
2. https://pubmed.ncbi.nlm.nih.gov/14557344/
3. https://www.ahajournals.org/doi/10.1161/01.cir.0000091380.04100.84
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5. https://www.acc.org/Latest-in-Cardiology/ten-points-to-remember/2019/09/10/12/36/2019-ESC-Guidelines-for-Supraventricular-Tachycardia

2. European Society of Cardiology Guidelines on Cardiac Pacing and Resynchronization Therapy

1. https://www.escardio.org/Guidelines/Clinical-Practice-Guidelines/Cardiac-Pacing-and-Cardiac-Resynchronization-Therapy
2. https://academic.oup.com/eurheartj/article/42/35/3427/6358547
3. https://pubmed.ncbi.nlm.nih.gov/34455430/
4. https://academic.oup.com/eurheartj/article/34/29/2281/401445
5. https://pubmed.ncbi.nlm.nih.gov/23801827/