From the Guidelines
Right bundle branch block (RBBB) is significantly associated with ischemic heart disease, with a 64% increased odds ratio of in-hospital death compared to patients without bundle branch block 1. The relationship between RBBB and ischemic heart disease is complex, with RBBB potentially occurring as a consequence of myocardial ischemia or infarction, particularly when the right bundle branch's blood supply is compromised during an acute coronary event. In patients with acute myocardial infarction, the development of RBBB often indicates more extensive cardiac damage and is associated with higher mortality rates compared to patients without conduction abnormalities 1. Some key points to consider include:
- The presence of RBBB in a patient with chest pain should raise suspicion for possible coronary artery disease, especially when the RBBB is new-onset.
- RBBB can occur in approximately 5% to 10% of acute myocardial infarction patients 1.
- Patients with RBBB have similar outcomes, if not worse, compared to patients with left bundle branch block (LBBB) 1.
- The underlying mechanism involves damage to the specialized conduction tissue in the right bundle, leading to delayed activation of the right ventricle and the characteristic ECG pattern of RBBB with wide QRS complexes and specific morphological features in the right precordial leads. When RBBB is discovered in a patient with risk factors for coronary artery disease, further cardiac evaluation is typically warranted to determine the underlying cause and to guide management 1.
From the Research
Association between RBBB and Ischemic Heart Disease
- The presence of Right Bundle Branch Block (RBBB) has been associated with a higher risk of mortality and cardiovascular morbidity in patients with ischemic heart disease 2, 3, 4, 5.
- Studies have shown that patients with acute myocardial infarction (AMI) and RBBB have a higher risk of long-term mortality, ventricular arrhythmia, and cardiogenic shock compared to those without RBBB 2.
- The presence of RBBB may lead to the misdiagnosis of transmural ischemia and mask the early diagnosis of ST-elevation myocardial infarction 2.
- New-onset RBBB is occasionally caused by AMI, and patients with new-onset RBBB have a higher risk of long-term mortality and cardiovascular morbidity compared to those with previous RBBB 2.
- The European Society of Cardiology guideline recommends considering RBBB as a high-risk factor for mortality in patients with suspected myocardial infarction, and urgent angiography should be considered in these patients 4.
Prevalence and Incidence of RBBB
- The prevalence of RBBB in the general population is around 3-8%, with a higher prevalence among men and elderly patients 5.
- The incidence of RBBB is associated with male sex and age, and patients with incomplete RBBB who progress to complete RBBB have a higher incidence of heart failure and chronic kidney disease 5.
Comparison with Other Conditions
- The risk of mortality and cardiovascular morbidity associated with RBBB is comparable to that of left bundle branch block (LBBB) and bifascicular block (BFB) 4, 5.
- The use of angiotensin-converting enzyme inhibitors or angiotensin II-receptor blockers may reduce the risk of mortality and myocardial infarction in patients with ischemic heart disease, but the evidence is limited for patients with RBBB 6.