Predictors and prognostic impact of arrhythmic complications in ST-segment elevation myocardial infarction

Abstract Background Despite advancements in revascularisation techniques, ST-segment elevation myocardial infarction (STEMI) still implicates a high risk of short and long-term mortality, mechanical and electrical complications. However, the risk factors and prognostic significance of arrhythmias in STEMI are not yet fully clarified. Aim To identify clinical and instrumental predictors of arrhythmic complications in STEMI and to assess their prognostic impact on in-hospital and long-term mortality. Methods STEMI patients from the AMIPE registry were enrolled from 2017 to 2023. Clinical and instrumental parameters related to the index hospitalization were collected. Bradyarrhythmias (high grade atrioventricular and sinoatrial block), atrial fibrillation development (AF), and ventricular arrhythmias (VA; sustained ventricular tachycardia or ventricular fibrillation) during the hospitalization were registered. Univariable and multiple logistic regressions were used to establish the predictors of arrhythmias and their association with in-hospital mortality. Univariable and multiple Cox regression were used to estimate adjusted hazard ratios (aHR) and 95% confidence intervals (95%CI) for each candidate predictors of mortality during long term follow-up, up to 60 months. Results 2206 STEMI patients were enrolled with a mean age of 70±14 years. 131 (5.9%) subjects developed a bradyarrhythmia, 216 (9.8%) had AF, and 144 (6.5%) presented a VA. Independent predictors of bradyarrhythmias were age, female sex, high white blood count, and culprit lesion in the right coronary artery (p0.05 for all). Independent predictors of AF were age, beta-blockers, lower ejection fraction (EF) and presentation 12 hours after symptom onset (p0.05 for all). Independent predictors of VA were high blood count and lower EF at admission (p0.01 for both). 142 (6.4%) of patients died in-hospital. The occurrence of VA as a complication of STEMI was independently associated with increased in-hospital mortality (OR 3.26; 95%CI 1.68-6.33). Conversely, bradyarrhythmias and AF was predictive of in-hospital mortality in univariate analysis, but not in multivariable models. 217 patients discharged at home died during follow-up (10.5%). AF was the only arrhythmia associated with long-term mortality (HR 3.19; 95%CI 2.30-4.42), even after adjustment for other relevant risk factors (aHR 1.70; 95%CI 1.21-2.40). Conclusions In STEMI, ventricular arrhythmias represent a strong independent predictor of in-hospital mortality, whereas bradyarrhythmias and AF appear to reflect the impact of underlying comorbidities rather than directly influencing short-term prognosis. On the contrary, AF emerged as the only arrhythmia complicating the early phases of a STEMI independently associated with an increased risk of death during long-term follow-up. These findings highlight the importance of targeting the early development of arrhythmias after STEMI to improve clinical outcomes in these high-risk patients.Bradiarrhythmias and VA AF