- Among patients with suspected myocardial infarction (MI):
- Right bundle branch block (RBBB) incidence is low;
- MI likelihood is similar with RBBB vs no bundle branch block (BBB); and
- RBBB is not associated with increased mortality after adjusted analysis.
- Authors: “our data do not support an urgent coronary angiography in patients with RBBB and suspected MI in the absence of ST-segment elevation, hence questioning the diagnostic criteria of RBBB alone as a ST-segment elevation equivalent.”
Why this matters
- Based on 1 study, 2017 European Society of Cardiology (ESC) guidelines recommend RBBB trigger urgent angiography for patients with ST-elevation MI (STEMI).
- Unclear if applicable to emergency department, suspected MI.
- 3.1% (125) had RBBB, 6.9% (281) left BBB (LBBB), and 1.5% (60) bifascicular block (BFB).
- 20.8% (846/4067) had MI, most non-STEMI.
- MI incidence:
- With RBBB: 18.4% (23);
- With LBBB: 27.0% (76);
- Without BBB: 20.4% (734).
- Median follow-up, 731 days.
- Adjusted HRs for mortality (95% CIs):
- RBBB: 1.29 (0.71-2.34; P=.40);
- LBBB: 1.71 (1.17-2.50; P=.006);
- BFB: 2.27 (1.28-4.05; P=.005).
- Analysis, 2 prospective studies of patients presenting to emergency departments with suspected MI (n=4067).
- Final MI diagnosis adjudicated.
- Outcome: all-cause mortality.
- Funding: Abbott Diagnostics; German nonprofit organizations.
- Low RBBB rate.