Impact of Glomerular Filtration Rate on the Incidence and Prognosis of New-Onset Atrial Fibrillation in Acute Myocardial Infarction.

Background: Atrial fibrillation (AF) is a frequent complication of acute myocardial infarction (AMI) and is associated with a worse prognosis. Patients with chronic kidney disease are more likely to develop AF. Whether the association between AF and glomerular filtration rate (GFR) is also true in AMI has never been investigated. Methods: We prospectively enrolled 2445 AMI patients. New-onset AF was recorded during hospitalization. Estimated GFR was estimated at admission, and patients were grouped according to their GFR (group 1 (n = 1887): GFR >60; group 2 (n = 492): GFR 60-30; group 3 (n = 66): GFR <30 mL/min/1.73 m(2)). The primary endpoint was AF incidence. In-hospital and long-term (median 5 years) mortality were secondary endpoints. Results: The AF incidence in the population was 10%, and it was 8%, 16%, 24% in groups 1, 2, 3, respectively (p < 0.0001). In the overall population, AF was associated with a higher in-hospital (5% vs. 1%; p < 0.0001) and long-term (34% vs. 13%; p < 0.0001) mortality. In each study group, in-hospital mortality was higher in AF patients (3.5% vs. 0.5%, 6.5% vs. 3.0%, 19% vs. 8%, respectively; p < 0.0001). A similar trend was observed for long-term mortality in three groups (20% vs. 9%, 51% vs. 24%, 81% vs. 50%; p < 0.0001). The higher risk of in-hospital and long-term mortality associated with AF in each group was confirmed after adjustment for major confounders. Conclusions: This study demonstrates that new-onset AF incidence during AMI, as well as the associated in-hospital and long-term mortality, increases in parallel with GFR reduction assessed at admission.