Comparative diagnostic and prognostic implications of right versus left bundle branch block in patients with suspected ST-segment elevation myocardial infarction

Abstract Background Current ESC guidelines on management of acute myocardial infarction in patients presenting with ST-segment elevation (STEMI) recommend emergent invasive ischemic symptoms and bundle branch block (BBB). While left (LBBB) is a well-known high-risk feature infarction, data the diagnostic prognostic impact right (RBBB) comparison to LBBB context STEMI are scarce. Methods A prospective cohort 2,139 suspected were triaged by on-call cardiologist coronary angiography based prehospital, tele-transmitted digital 12-lead electrocardiogram. All discharge diagnoses independently adjudicated. The accuracy RBBB or was calculated. 30-day 1-year all-cause mortality from central national registry compared for LBBB, without BBB using Kaplan Meier method. Unadjusted adjusted (age, sex, hypertension, hyperlipoproteinemia, smoking status history artery disease) hazard ratios calculated both BBB-types. Results final diagnosis adjudicated 1,832/2,139 (85.6%) patients. present 117 (5.5%), 61 (2.9%) patients, respectively. Patients older than non-BBB patients: Median age 69.7 years RBBB, 68.9 62.6 Comparing types, more often had prior heart failure (6.3% vs 11.5% LBBB), while developed cardiac arrest before (15.3% 3.7% respectively) frequently revealed Thrombolysis Myocardial Infarction (TIMI) grade flow 0 (61.0% 47.2%, respectively). Specificity not significantly different BBB-types: 95.1% (95% CI 92.1–97.0) versus 92.8% 89.4–95.2) (p=0.25). higher (Figure 1), showed similar outcome. ratio comparing 3.35 2.11–5.34, p<0.001) 1.4 0.57–3.44, p=0.46) when After adjustment 2.3 1.25–4.21, p=0.007). Conclusion In STEMI, an ominous sign associated adverse clinical features like PCI, TIMI flow, presenters. Consequently, poorer outcome after 12 months. Our therefore reinforce current designating RBBB-patients as very high-risk, demanding immediate triage. Funding Acknowledgement Type funding sources: Public grant(s) – National budget only. Main source(s): Regional Research Foundation Region Sjaelland, Denmark