Long-term prognostic impact of new-onset atrial fibrillation in patients with preserved and mildly reduced ejection fraction following myocardial infarction

Abstract

Abstract Funding Acknowledgements Type of funding sources: None. Background/aim It is well known that atrial fibrillation (AF) significantly increases risk of short- and long-term mortality in patients with ST-elevation myocardial infarction (STEMI), especially in those with reduced left ventricular ejection fraction (EF), but its prognostic impact in patients with STEMI and preserved or mildly reduced EF is not well defined. The aim of this study was to analyse the prognostic impact of new-onset AF on long-term mortality in patients with preserved and mildly reduced EF after STEMI. Method we included 1874 consecutive STEMI patients treated with primary percutaneous coronary intervention (pPCI). New-onset AF was defined as electrocardiographic or monitoring evidence of a AF lasting at least 30 seconds in patients with no medical history of previous AF. Echocardiographic examination was performed before discharge, EF was calculated using bi-plane method. Preserved EF was defined as ≥50% and midly reduced EF was defined as EF 41-49%. Patients with cardiogenic shock at admission and patients with previous AF of any form (paroxysmal, persistent or permanent) were excluded. The follow-up period was 6 years. Results Among all analysed patients 491 (26.6%) patients were women and 1375 (73.4%) were men. The median age of all analysed patients was 58 (IQR 46, 69) years and median EF was 52% (IQR 45%, 57%). New-onset AF was registered in 78 (4.2%) patients. Among them 27 (34.6%) patients had AF at admission and 51 (65.4%) patients develop AF later at a median time 4 (IQR 1, 25) hours. Median duration of AF was 17 (IQR 6, 25) hours. All of the analyzed patients with new-onset AF were converted into sinus rhythm with medication (amiodarone) or they converted spontaneously upon myocardial revascularization. As compared with patients without AF, those with AF were older and presented more often with Killip class II and III; they had lower systolic blood pressure and creatinine clearance at admission; they had more often 3-vessel coronary artery disease (at initial angiogram), preprocedural flow TIMI=0 and postprocedural flow TIMI<3. EF values were similar among patients with and without AF 50% (IQR 44%, 55%) and 51% (IQR 45%, 55%) respectively, p=0.93. Six-year mortality was significantly higher in patients with new-onset AF as compared with patients without AF (14.1% vs 2.6%, respectively, p<0.001) as shown in Figure 1. In Cox regression model new-onset AF was an independent predictor of 6-year mortality–HR 4.53 (95% CI 2.29-8.94), p<0.001. Other independent predictors for 6-year mortality were older age, Killip class II and III at admission and baseline creatinine clearance <60ml/min/m2. Conclusion New-onset AF was a strong indepedent predictor for 6-year mortality in analyzed patients with preserved and mildly reduced EF after STEMI.