Impact of new-onset versus preexisting atrial fibrillation on short- and long-term mortality in patients with STEMI treated with primary PCI

Abstract

Abstract Background Comparative data on the effects of new-onset vs. preexisting atrial fibrillation (AF) on long-term mortality in patients with ST-elevation myocardial infarction (STEMI) treated with primary percutaneous coronary intervention (PCI) are scarce. Therefore, the aim of this study was to assess the impact of new-onset vs. preexisting AF on mortality over 5 years after primary PCI. Methods Our analysis included 7 955 patients referred to primary PCI in the period from 2009 to 2019, for whom data regarding the presence and type of AF were available, from a prospective electronic registry of a high-volume catheterization laboratory. Patients were stratified into three groups according to the AF status: no AF vs. new-onset vs. preexisting AF. Cumulative mortality was compared with Kaplan Meier curves. Cox regression models were created to assess the mortality hazard at 30 days and 5 years according to the presence of new-onset and preexisting AF with no AF as the reference group. 30-day follow-up was available for 7 738 and 5-year for 5 049 patients. Results Preexisting AF was found in 3.1% of patients (n=246) and new-onset AF was recorded in 7.0% (n=560). Both new-onset and preexisting AF were associated with higher crude mortality rates compared to patients without AF, at 30 days (14.4% vs 16.0% vs. 5.2%, respectively; p<0.001) and at 5 years as well (56.6% vs. 65.7% vs. 25.4%, respectively; p<0.001). Cumulative mortality rates were significantly higher for both new-onset and preexisting AF, as compared to patients with no AF (Log rank p<0.001, Figure). Patients with new-onset and preexisting AF were older and had a higher baseline risk profile including more frequently prior MI and stroke, more diabetes, hypertension, hyperlipidaemia, renal failure, Killip class ≥2 on admission and lower ejection fraction. When adjusted for these baseline differences, both new-onset and pre-existing AF independently predicted 5 year mortality (HR 1.6, 95%CI 1.4-1.9, p<0.001, and HR 2.2, 95%CI 1.8-2.8, p<0.001, respectively), but not at 30 days (HR 1.4, 95%CI 0.9-2.0, p=0.1, and HR 1.5 95%CI 0.9-2.5, p=0.1, respectively). Conclusion Both new-onset and pre-existing AF are independently associated with an increased risk of long-term mortality in patients with STEMI treated with primary PCI, whereas their impact on short-term mortality reflects the higher baseline risk profile of those patients.Cumulative mortality rates