Abstract
Introduction
New onset AF is a known complication in patients with acute ST-segment elevation myocardial infarction (STEMI). However, whether new-onset AF affects the long-term prognosis to the same extent as pre-existing AF is not fully clarified and prescription of oral anticoagulants (OAC) in patients with new-onset AF remains a matter of debates.
Purpose
We aimed to assess the impact of new-onset AF in STEMI patients undergoing primary percutaneous intervention (PCI) on outcome during long-term follow-up in comparison with pre-existing AF and to evaluate effect of OAC therapy in patients with new-onset AF on survival.
Methods
Study sample comprised of 2277 consecutive patients with STEMI admitted to a tertiary care hospital for primary PCI from 2007 to 2010 (age 66±12 years, 70% male). AF prior to STEMI was documented by record linkage with the Swedish National Patient Register and review of ECGs obtained from the digital archive containing ECGs recorded in the hospital catchment area since 1988. SWEDEHEART registry was used as the source of information regarding clinical characteristics and events during index admission, including new-onset AF and OAC at discharge. All-cause mortality was assessed using the Swedish Cause-of-Death Register 8 years after discharge.
Results
AF prior to STEMI was documented in 177 patients (8%). Among patients without pre-existing AF (n=2100), new-onset AF was identified in 151 patients (7%). Patients with new-onset AF were older than those without AF history (74±9 vs 65±12 years, p<0.001), but did not differ in regard to other clinical characteristics. Among 2149 STEMI survivors discharged alive, 523 (24%) died during 8 years of follow-up. OAC was prescribed at discharge in 45 (32%) patients with new onset AF and in 49 (31%) patients with pre-existing AF, p=0.901. In a univariate analysis, both new-onset AF (HR 2.18, 95% CI 1.70–2.81, p<0.001) and pre-existing AF (HR 2.80, 95% CI 2.25–3.48, p<0.001) were associated with all-cause mortality, Figure 1. After adjustment for age, gender, cardiac failure, diabetes, BMI and smoking history, new-onset AF remained an independent predictor of all-cause mortality (HR 1.40, 95% CI 1.02–1.92, p=0.037). OAC prescribed at discharge in patients with new-onset AF was not significantly associated with survival (univariate HR 0.86, 95% CI 0.50–1.50, p=0.599).
Conclusion
New-onset AF developed during hospital admission with STEMI is common and independently predicts all-cause mortality during long-term follow-up after STEMI with risk estimates similar to pre-existing AF. The effect of OAC on survival in patients with new-onset AF is inconclusive as only one third of them received OAC therapy at discharge.
Kaplan-Meier survival curve
Funding Acknowledgement
Type of funding source: None
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