Unlike LBBB, right bundle branch block (RBBB) is less a therapeutic target than a prognostic marker — and recent data suggest it carries more weight than once thought. A large UK Biobank cohort found RBBB independently associated with higher risks of ischemic stroke, atrial fibrillation, and all-cause mortality. In acute myocardial infarction treated with PCI, atypical RBBB predicts in-hospital sudden cardiac death and cardiac rupture, and RBBB in suspected STEMI marks a higher-risk course. For patients with syncope and bifascicular block that includes RBBB, a SPRITELY substudy showed pacemaker implantation substantially reduced major events. The practical message is that RBBB — particularly when new, atypical, or accompanied by syncope or infarction — warrants attention as a risk marker rather than being dismissed as benign.
Further reading: RBBB and ischemic stroke (UK Biobank, Park et al., 2025); SPRITELY substudy on bifascicular block (Neira et al., Heart Rhythm 2023); atypical RBBB in acute MI (Yang et al., JAHA 2025).