From the Guidelines
Right bundle branch block (RBBB) is most commonly caused by coronary artery disease, degenerative changes in the cardiac conduction system, congenital heart defects, cardiomyopathies, and pulmonary conditions, as supported by the European Heart Journal study 1. The causes of RBBB can be diverse and include:
- Coronary artery disease, particularly right ventricular infarction
- Degenerative changes in the cardiac conduction system associated with aging
- Congenital heart defects such as atrial septal defects, ventricular septal defects, and tetralogy of Fallot
- Cardiomyopathies, including hypertrophic and dilated types
- Myocarditis and infiltrative diseases like sarcoidosis and amyloidosis
- Pulmonary conditions such as pulmonary embolism, pulmonary hypertension, and cor pulmonale
- Cardiac surgeries, particularly valve replacements and repair of congenital defects
- Electrolyte disturbances, certain medications, and genetic disorders affecting cardiac conduction According to the study 1, bundle branch block may develop as a consequence of a primary degenerative lesion of the specialized conducting tissue or from a variety of cardiac pathologies. It is essential to note that RBBB can sometimes be found in otherwise healthy individuals, particularly athletes, and may not always indicate underlying heart disease, as reported in the European Heart Journal study 1. In clinical practice, the presence of RBBB should prompt a thorough evaluation to rule out underlying cardiac or pulmonary disease, as the prognosis and management of RBBB depend on the underlying cause, as suggested by the study 1.
From the Research
Causes of Right Bundle Branch Block
The causes of right bundle branch block (RBBB) can be attributed to various factors, including:
- Cardiac failure with associated asynchrony of the left ventricle 2
- Right ventricular dilatation encountered in congenital heart disease 2
- Coronary artery disease (CAD), although the relationship between RBBB and CAD is still unclear 3, 4
- Myocardial infarction (MI), with RBBB being associated with more severe damage of the inferior wall of the left ventricle 3
Association with Coronary Artery Disease
Studies have investigated the association between RBBB and CAD, with some findings suggesting:
- No significant difference in the incidence of CAD between patients with RBBB and those without 4
- No association between RBBB and the presence and severity of CAD 4
- RBBB may be associated with more severity of stenosis in the left coronary system, but not with the overall presence and severity of CAD 4
Prognostic Implications
The prognostic implications of RBBB are still uncertain, with some studies suggesting:
- RBBB may not be a predictor of coronary artery disease 4
- RBBB or bifascicular block may not offer any clinical utility when evaluating patients with suspected acute myocardial infarction 5
- Individuals with RBBB may not be associated with an increased risk of subclinical coronary atherosclerosis compared to those without RBBB 6