Right bundle branch block in suspected acute coronary syndromes: Diagnostic challenges, treatment and prognosis
Juliana Senftinger1, Nils A Sörensen2, Stefan Blankenberg2
1Department of Cardiology, University Heart and Vascular Center Hamburg and Center for Population Health Innovation (POINT), Hamburg, Germany.
Insights
Right bundle branch block (RBBB) may indicate increased cardiovascular risk in the general population. In acute coronary syndrome (ACS) patients, RBBB warrants invasive evaluation, even without typical ECG changes, to identify potential ST-elevation myocardial infarction (STEMI).
Area of Science:
- Cardiology
- Electrophysiology
- Internal Medicine
Background:
- Conflicting evidence exists on the prognostic significance of right bundle branch block (RBBB) in the general population and acute coronary syndrome (ACS) patients.
- Current guidelines consider RBBB in ACS as a STEMI equivalent, but recent research suggests a need for further differentiation.
- Previous studies often viewed RBBB as benign, but emerging data links it to increased cardiovascular morbidity and mortality.
Purpose of the Study:
- To review the prognostic implications of RBBB in the general population and ACS patients.
- To evaluate the association of RBBB with cardiovascular outcomes and diagnostic accuracy for ST-elevation myocardial infarction (STEMI).
- To inform clinical practice regarding the management of ACS patients with RBBB.
Main Methods:
- A literature search was conducted in PubMed and Google Scholar.
- Analysis of previous studies on RBBB prevalence, associated mortality, and angiographic findings in suspected ACS.
- Review of diagnostic accuracy of STEMI criteria in the presence of RBBB.
Main Results:
- RBBB is associated with increased cardiovascular morbidity and mortality in the general population.
- In suspected ACS, RBBB prevalence was 3% and linked to elevated mortality, with similar culprit artery identification rates compared to other ECG presentations.
- In high-risk ACS patients, RBBB (12% prevalence) correlated with poorer outcomes, but STEMI diagnostic accuracy was unaffected; however, many RBBB patients without clear STEMI signs had acute STEMI on angiography.
Conclusions:
- Patients with RBBB and risk factors in the general population may require further cardiovascular evaluation.
- Current guidelines recommending acute invasive evaluation for high-risk ACS patients with RBBB are supported.
- In unselected ACS patients, RBBB necessitates considering differential diagnoses and may benefit from immediate cardiac catheterization if STEMI is suspected despite non-specific ECG findings.
Background:
There is still conflicting evidence regarding the prognostic implications of right bundle branch block (RBBB) in the general population but also in patients with heart diseases like acute coronary syndromes (ACS). In accordance with current guidelines, RBBB in ACS patients is considered as STEMI equivalent. However, recent studies indicate that further differentiation is necessary in this group, as we will outline below.
Methods And Results:
A literature search was conducted in PubMed and Google Scholar. In previous studies, RBBB in the general population were mostly considered benign changes of the electrical conduction system. However, recent studies indicate that both complete and incomplete RBBB are associated with increased cardiovascular morbidity and mortality. In addition, among unselected patients with suspected ACS presenting to the emergency department, the prevalence of RBBB was 3 % and it was associated with elevated mortality. The subsequent angiographic identification of a culprit coronary artery stenosis leading to stent implantation was similar at approximately 2 % regardless of the initial ECG presentation with narrow QRS complexes, left bundle branch block (LBBB), or RBBB. Finally, in a group of high-risk patients for ST-elevation myocardial infarction (STEMI), the prevalence of RBBB was 12 %. While RBBB was associated with poor outcome compared to non-BBB and LBBB patients, diagnostic accuracy of STEMI criteria was not affected by the presence of RBBB. However, RBBB patients without distinct STEMI signs in ECG often showed acute STEMI on angiography indicating a potential benefit from immediate transfer to the cardiac catheterization laboratory.
Conclusion:
In the general population, patients with RBBB and risk factors may need further evaluation. Regarding ACS patients, recent studies support current guidelines that recommend acute invasive evaluation for high-risk ACS patients with RBBB, regardless of ST-T deviations. However, in an unselected group of ACS patients, differential diagnoses should also be investigated through additional diagnostic procedures.
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