Incidentally Induced Atrial Fibrillation During Programmed Electrical Stimulation in Patients With Depressed Left Ventricular Systolic Function After an Acute Myocardial Infarction

ABSTRACT Background The aim of this study was to investigate the clinical implication of incidentally induced atrial fibrillation (AF) during programmed electrical stimulation (PES) in patients with left ventricular systolic dysfunction (≤40%) after an acute myocardial infarction (MI). Methods In this study, we included 231 patients from the Cardiac Arrhythmias and RIsk Stratification after Myocardial InfArction (CARISMA) study with left ventricular ejection fraction ≤40% and no prior history of AF. These patients underwent PES 6 weeks post‐MI as part of the study protocol. Patients all received an implantable cardiac monitor (ICM) 3–21 days post‐MI and were continuously monitored for cardiac arrhythmias for 2 years. Induction of AF was unwanted but reported if this incidentally occurred. Results A total of 61 patients (26%) developed AF within 2 years of follow‐up, in which n = 10 (29%) had incidental AF during PES at baseline. The overall risk of AF was not significantly increased in patients with incidental AF (n = 34) during PES compared to patients without incidental AF (n = 197) (HR 1.6 [0.9–3.0], p = 0.14). The risk of bradyarrhythmia (HR = 0.2 [0.0–1.2], p = 0.07), ventricular arrhythmias (HR = 0.7 [0.1–5.8], p = 0.77), and major cardiovascular events (MACE) (HR 0.5 [0.2–1.7], p = 0.28) was not significantly different in patients with versus without incidental AF. Conclusions Incidentally induced AF during PES in post‐MI patients with reduced LVEF was not significantly associated with a higher risk of long‐term atrial fibrillation, other cardiac arrhythmias, or major cardiac events. Trial Registration NCT00145119