AF Recurrence in Patients With Transient New-Onset AF

Quick Takes

  • Patients with a first-time episode of atrial fibrillation (AF) during hospitalization for medical illness or noncardiac surgery (NCS), in whom sinus rhythm was restored at time of hospital discharge, had a one in three chance of AF recurrence within a 12-month follow-up period.
  • By comparison, age- and sex-matched controls exhibited a 1 in 20 chance of first-time onset AF during a 12-month follow-up period, indicating a relative risk of 6.6 for subsequent AF in patients with a transient AF episode during hospitalization compared to matched controls with no observed AF prior to or during index hospitalization.
  • A majority of subsequent AF events after hospital discharge were detected by wearable monitor as opposed to clinical encounter.

Study Questions:

What is the rate of atrial fibrillation (AF) recurrence within 12 months after discharge in patients whose AF was documented for the first time during hospitalization for noncardiac surgery (NCS) or medical illness?


Patients at three academic hospitals in Hamilton, Ontario with a documented first-time episode of AF during hospitalization for medical illness or NCS, no known prior AF diagnosis, and who returned to sinus rhythm at the time of hospital discharge were eligible to participate in this study. Subjects were followed for 1 year, by 14-day rhythm monitoring by a wearable patch at 1 month and 6 months, and by telephone follow-up at 1 month, 6 months, and 1 year after hospital discharge.

The primary outcome was any AF episode lasting ≥30 seconds, detected by wearable monitor or during clinical care. Secondary outcomes included time from discharge to AF recurrence, total AF burden, total AF duration, longest AF episode, adverse events (death, heart failure, stroke, bleeding, or hospitalization for myocardial infarction or heart failure), and use of anticoagulation within 12 months after enrollment. Patients from the same hospital units with no AF history, matched by age and sex, were recruited as controls. Sensitivity analysis was performed comparing indication for index hospitalization (medical illness vs. NCS), cases treated with electrical or chemical cardioversion compared to those in which the AF terminated spontaneously, and subjects whose postdischarge AF diagnosis was based on clinical encounter versus wearable patch.


A total of 139 cases and 139 matched controls were included in the analysis. The primary outcome (AF recurrence within 1 year of hospital discharge) occurred in 33.1% (95% confidence interval [CI], 25.3-40.9) of cases versus 5.0% (95% CI, 1.4-8.7) of controls by the end of the 12-month follow-up period, for an adjusted relative risk of 6.6 (95% CI, 3.2-13.7). Method of AF detection during the follow-up period was by wearable patch 70% of the time, clinical care 13% of the time, and a combination 17% of the time. The longest single AF episode and total AF duration were similar in cases versus controls (median 7.9 vs. 9.8 hours, and 8.9 vs. 9.8 hours).

Total incidence of the following events was observed among cases versus controls during the follow-up period:

  • Emergency room visit (11 vs. 5)
  • Rehospitalization (12 vs. 6)
  • Follow-up with specialist for management of AF (55 vs. 10)
  • Stroke (1 vs. 1)
  • Thromboembolus (2 vs. 0)
  • Myocardial infarction (3 vs. 0)
  • Heart failure (3 vs. 1)
  • Bleeding (6 vs. 4)
  • Death (11 vs. 7)
  • Use of anticoagulation (73% vs. 39%)


Patients having first-time AF diagnosis during hospitalization for NCS or medical illness, and who were discharged from hospital in sinus rhythm, had a nearly 7-fold greater risk of AF recurrence within 1 year of discharge versus patients with no prior AF episode before or during hospitalization. This elevated relative risk was consistent across subgroups.


In this study, the long-term implications of AF diagnosed for the first time during hospitalization that may have involved considerable physiologic stress were explored. Results indicate roughly one in three affected patients will have future AF episodes within 12 months of hospital discharge, and suggest that these patients will benefit from referral to a specialist who can provide expert advice on risk reduction strategies.

Clinical Topics: Anticoagulation Management, Arrhythmias and Clinical EP, Heart Failure and Cardiomyopathies, Prevention, Anticoagulation Management and Atrial Fibrillation, Atrial Fibrillation/Supraventricular Arrhythmias, Acute Heart Failure

Keywords: Anticoagulants, Atrial Fibrillation, General Surgery, Heart Failure, Secondary Prevention

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