New Onset Versus Known Atrial FIbrillation and Mortality in STEMI

Background: Atrial fibrillation (AF) is a common arrhythmic complication in the setting of ST Elevation MI (STEMI) and is associated with increased 30-day mortality. However, data on the long-term prognostic implications of New-Onset AF (NOAF) complicating STEMI in the era of complete revascularization remain controversial. Our aim therefore was to evaluate the long-term consequences of prior AF and new-onset AF (NOAF) in STEMI patients undergoing percutaneous coronary intervention (PCI).

Methods: We analyzed data from our prospective registry of 1657 consecutive patients hospitalized in the Cardiac Intensive Care Unit (CICU) with STEMI during the 7-year period of 2008-2014. Patient records were reviewed for the occurrence of prior AF and NOAF. NOAF was defined as AF occurring within 30 days of the STEMI episode.

Results: Patients were followed for a mean of 1327 days. Within our cohort, 150 (9%) patients had AF at any time, with 73 (48.7%) having a diagnosis of prior AF and 52 (34.7%) with NOAF. Patients with AF at any time were older with reduced systolic function and had a significantly increased 30-day mortality (6.7% vs. 2.1%, p=0.00). NOAF was not associated with higher 30 days and all-cause mortality. Prior AF conferred a significantly increased rate of 30-day mortality (11.4% vs. 2.1%, p=0.00). Within patients presenting AF during the index hospitalization, patients with prior AF had significantly increased long-term mortality rate (30% vs. 8.4%, p=0.00). Interestingly, CHADS2 score was not different among patients with and without AF.

Conclusion: The presence of prior AF in STEMI patients treated with PCI is associated with more than 5-fold increase in 30-day and nearly 4-fold increase in long term mortality.