In-Hospital Outcomes of Patients with Right Bundle Branch Block (RBBB) and Anterior Wall ST-Segment Elevation Myocardial Infarction (AW STEMI) Undergoing Primary Percutaneous Coronary Angioplasty

https://doi.org/10.5281/zenodo.17585668

Abstract

Background: Anterior wall ST-segment elevation myocardial infarction (AW-STEMI) with right bundle branch block (RBBB) signals extensive septal ischemia and may portend higher in-hospital risk despite contemporary primary percutaneous coronary intervention (PPCI).

Objective: To estimate in-hospital outcomes and identify bedside predictors of mortality among patients with AW-STEMI and RBBB treated with PPCI in a standardized care pathway.

Methods: We performed a descriptive cross-sectional study at a tertiary cardiac center using consecutive enrollment over six months. Adults (≥18 years) with AW-STEMI and RBBB undergoing PPCI within 24 hours were included; prior MI/CABG, significant valvular disease/cardiomyopathy, or refusal of consent were exclusions. Prespecified outcomes were abstracted via a standardized case-report form. Continuous data are reported as mean (SD) or median (IQR); categorical data as n/N (%). A parsimonious multivariable logistic model (events-per-parameter constrained) explored predictors of in-hospital mortality.

Results: Of 146 activations, 130/146 (89.0%) met criteria (mean age 58.7 ± 11.8 years; male 104/130 [80.0%]). Median symptom-to-door time was 180 minutes (IQR 120–300); door-to-balloon 78 minutes (62–94), with >90 minutes in 39/130 (30.0%). Culprit was LAD in 120/130 (92.3%); proximal LAD 77/130 (59.2%). Pre-PCI TIMI 0 occurred in 89/130 (68.5%); post-PCI TIMI 3 in 117/130 (90.0%). In-hospital mortality was 12/130 (9.2%; 95% CI, 4.9–15.6). MACE occurred in 20/130 (15.4%; 9.7–22.8); reinfarction 5/130 (3.8%); stroke 3/130 (2.3%); VT/VF 14/130 (10.8%); complete heart block requiring pacing 11/130 (8.5%); acute heart failure 24/130 (18.5%); mechanical circulatory support 11/130 (8.5%). Median length of stay was 4 days (3–6). Killip III–IV independently predicted mortality (adjusted OR 3.85; 95% CI, 1.32–11.25); age per decade showed a moderate association (1.62; 1.08–2.64); symptom-to-door >180 minutes trended toward harm (2.27; 0.78–6.55). Model performance was fair (AUC 0.79; 95% CI, 0.68–0.90).

Conclusion: In AW-STEMI with RBBB, in-hospital risk concentrates among patients with shock physiology, older age, and treatment delays, and is mitigated when post-PCI TIMI 3 flow is achieved. System strategies to compress total ischemic time, prioritize early hemodynamic stabilization, and ensure meticulous reperfusion may reduce near-term mortality in this high-risk phenotype.