Design and rationale of the atrial fibrillation occurring transiently with stress (AFOTS) follow-up cohort study.

Atrial fibrillation occurring transiently with stress (AFOTS) describes the first detection of AF in a patient who is hospitalized for a non-cardiac medical illness or following non-cardiac surgery. Uncertainty exists whether episodes of AFOTS are due to reversible precipitants and will not recur after recovery, or if they are paroxysmal atrial fibrillation (AF) that is detected during inpatient cardiac monitoring. Previous studies have used retrospective, non-systematic and ultimately low-sensitivity protocols to investigate the recurrence of AF in patients with AFOTS. The prospective, multi-center, investigator-initiated AFOTS Follow-Up Cohort Study will enroll 138 case patients with AFOTS in the setting of non-cardiac surgery or medical illness, matched 1:1 with control patients for age, sex, stressor, and hospital unit. Participants will wear a 14-day ECG heart monitor at 1 and 6 months after hospital discharge. Over 12 months of follow-up, we will collect data regarding participant's medications, and clinical events. The primary endpoint is detection of 30 or more seconds of AF after hospital discharge. To date, 50% of the target sample has been enrolled. The study is expected to complete enrolment in mid-2019 and conclude 1 year later. The AFOTS follow-up study will employ a systematic protocol to detect AF and will provide a precise and valid estimate of AF recurrence following AFOTS. This study will establish whether patients with AFOTS have an increased propensity to AF after hospitalization as compared to matched controls and may inform the management of this population.