Anticoagulation vs. No AnticoagulationAnticoagulation for Stroke Prevention In Patients With Recent Episodes of Atrial Fibrillation Occurring Transiently With Stress

Inclusion Criteria:

1. have ≥1 episode of clinically important AFOTS during any of the following conditions:

1. noncardiac surgery in the past 35 days, with at least an overnight hospital admission aftersurgery;
2. noncardiac day surgery resulting in a large enough physiological insult to be able to cause AFOTS, as judged by the local investigator; or
3. acute medical illness requiring hospital admission in the past 35 days and resulting in a large enough physiological insult to be able to cause AFOTS, as judged by the local investigator;
2. sinus rhythm at the time of randomization;
3. any of the following high-risk criteria:

1. age 55-64 years, and having either known cardiovascular disease, recent major vascular surgery, a CHA2DS2VASc score ≥3, or an elevated postoperative troponin level;
2. age 65-74 years, and having either known cardiovascular disease, recent major vascular surgery, a CHA2DS2VASc score ≥2, or an elevated postoperative troponin level; OR
3. age ≥75 years.;
4. provide written informed consent

Exclusion Criteria:

1. any cardiac diagnosis as the primary reason for hospital admission;
2. history of documented chronic AF prior to noncardiac surgery;
3. need for long-term systemic anticoagulation;
4. ongoing need for long-term dual antiplatelet treatment;
5. contraindication to oral anticoagulation;
6. severe renal insufficiency (CrCl <20 ml/min);
7. severe liver cirrhosis (i.e., Child-Pugh Class C)
8. acute stroke in the past 14 days;
9. underwent cardiac surgery in the past 35 days;
10. history of nontraumatic intracranial, intraocular, or spinal bleeding;
11. hemorrhagic disorder or bleeding diathesis;
12. expected to be non-compliant with follow-up and/or study medications;
13. known life expectancy less than 1 year due to concomitant disease;
14. women who are pregnant, breastfeeding, or of childbearing potential who are not taking effective contraception; OR
15. previously enrolled in the trial