Prognostic implications of the 4S-AF scheme to characterize new-onset atrial fibrillation after myocardial infarction

Abstract

Aims: The 4S-AF scheme (Stroke risk [St], Symptom severity [Sy], Severity of atrial fibrillation burden [Sb], Substrate [Su]) is a novel approach for the holistic characterization of AF. We aimed to investigate the prognostic implications of the 4S-AF scheme score in acute myocardial infarction (AMI) patients with new-onset atrial fibrillation (NOAF).

Methods: We included 262 patients with post-MI NOAF who had complete data for the 4S-AF scheme evaluation between February 2014 and March 2018. The 4S-AF scheme score was calculated as a sum of each domain with a maximum of 9. The primary outcome was all-cause death.

Results: Of 262 patients (66.0% males, mean age 74.5 ± 10.4 years) were analyzed. The mean 4S-AF scheme score was 5.0 ± 1.6. There were 62 (27.3%) all-cause deaths within a median follow-up of 2.6 years. According to multivariable Cox regression models, each 1-point increase in the 4S-AF scheme score was significantly associated with 39% increased all-cause mortality (HR: 1.39, 95% CI: 1.16-1.67, P<0.001), which was mainly driven by the Sb (HR: 1.43, 95%CI: 1.05-1.95, P = 0.025) and Su (HR: 1.53, 95%CI: 1.17-2.02, P = 0.002) domains. Adding the 4S-AF scheme score on top of the Global Registry of Acute Coronary Events score could significantly improve its discriminative capability (C-index from 0.713 to 0.761, P = 0.039) and reclassification performance (continuous net reclassification improvement: 41.0% [95%CI: 12.5-69.6]; integrated discrimination improvement: 5.1% [95%CI: 2.2-8.1]) for all-cause mortality.

Conclusions: Characterization of NOAF using the 4S-AF scheme aids in the risk stratification of AMI patients with NOAF.

Keywords: 4S-AF scheme; Acute myocardial infarction; Decision curve analysis; New-onset atrial fibrillation.