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The aim of the SEARCH-AF trial is to evaluate a novel diagnostic tool for detecting post-operative atrial fibrillation or flutter (POAF/AFL) in cardiac surgical subjects during the early, sub-acute post-operative period. The population includes cardiac surgical subjects who have either developed or are at risk for developing new onset POAF/AFL and who are at risk for stroke, as determined by their CHA2DS2-VASC (congestive heart failure, hypertension, age ≥75 years (2 points), diabetes mellitus, previous stroke/transient ischemic attack (TIA) (2 points), vascular disease, age 65-74 years, sex class (female)) score. These subjects must not have had a history of AF/AFL before cardiac surgery.

The intervention group will undergo up to 30 days of continuous cardiac rhythm monitoring with an adhesive, patch-based monitor (Medtronic SEEQ™ mobile cardiac telemetry system or the CardioSTAT (Icentia Inc.) cardiac rhythm monitoring device). The control group will receive usual care, which does not involve planned cardiac rhythm testing within the first 30 days after study randomization. The primary outcome is documentation of sustained atrial fibrillation or flutter within the first 30 days after randomization. In addition, subjects in both groups will undergo 14 days of continuous cardiac rhythm monitoring with the Medtronic SEEQ™ mobile cardiac telemetry system or the CardioSTAT (Icentia Inc.) cardiac rhythm monitoring device at 6±1 months after their index cardiac surgery.

The aim of the SEARCH-AF trial is to evaluate a novel diagnostic tool for detecting post-operative atrial fibrillation or flutter (POAF/AFL) in cardiac surgical subjects during the early, sub-acute post-operative period. Its primary objective is to test whether enhanced cardiac rhythm monitoring with an adhesive, continuous monitor results in higher rates of atrial fibrillation or flutter (AF/AFL) detection at 30 days after randomization for post-cardiac surgical subjects who are at risk for developing post-operative atrial arrhythmias, when compared to usual care.

The study design is an open-label, two-arm randomized controlled trial (RCT) comparing a strategy of enhanced cardiac rhythm monitoring vs. usual care in 396 post-cardiac surgical subjects who are at risk for developing POAF/AFL.

The primary endpoint is the proportion of subjects with a cumulative AF/AFL burden of ≥6 minutes or documentation of AF/AFL by a 12-lead ECG within 30 days after randomization. Clinical endpoints will be adjudicated by an independent committee of physicians.

The study population involves post-cardiac surgical subjects at high risk of stroke, defined as having a CHA2DS2-VASC score of ≥4 or CHA2DS2-VASC of ≥2 with additional risk factors for developing POAF/AFL. These subjects must not have a history of AF/AFL pre-operatively.

Subjects who meet inclusion criteria will be randomized in a 1:1 ratio to one of the following 2 arms: (i) Enhanced cardiac rhythm monitoring (intervention group) or (ii) Usual care (control group). Subjects in the intervention group will receive up to 30 days of continuous cardiac rhythm monitoring with the Medtronic SEEQ™ mobile cardiac telemetry system or the CardioSTAT (Icentia Inc.) cardiac rhythm monitoring device. Monitoring will begin on the day of randomization. Subjects in the usual care group will not undergo protocol-mandated cardiac rhythm monitoring during the first 30 days after randomization.

All subjects will have a follow-up visit at 31-90 days after hospital discharge and at 6±1 months after surgery. At 6±1 months, all subjects will undergo 14 days of continuous cardiac rhythm monitoring with the SEEQ™ mobile cardiac telemetry system or the CardioSTAT (Icentia Inc.) cardiac rhythm monitoring device. A telephone follow-up will be performed for all subjects at 9±1 months after surgery.

Inclusion Criteria:

1. Male or female age ≥18 years.

2. Isolated CABG or valve replacement/repair +/- CABG performed at the index surgical procedure.

3. At elevated risk of stroke and for having POAF/AFL, defined as having a CHA2DS2-VASC (congestive heart failure, hypertension, age ≥75 years (2 points), diabetes mellitus, previous stroke/transient ischemic attack (TIA) (2 points), vascular disease, age 65-74 years, sex class (female)) score of ≥4 or ≥2 with at least 1 of the following risk factors for developing POAF/AFL:

   (i) Chronic obstructive pulmonary disease; (ii) Sleep apnea; (iii) Impaired renal function (defined as creatinine clearance <60 ml/min/1.73m2 or <60 ml/min); (iv) Echocardiographic evidence of at least mild left atrial enlargement (defined as ≥41 mm on M-mode, ≥59 ml or ≥29 mL/m2 on biplane volume assessment from an echocardiogram performed within 12 months of study enrollment); (v) Elevated body mass index (defined as BMI ≥30); (vi) Combined surgery (CABG + valve repair/replacement).

4. Able to provide written informed consent.

Exclusion Criteria:

1. Atrial fibrillation or flutter at the time of randomization.
2. Known previous history of AF/AFL, diagnosed pre-operatively (note: documentation of a history of AF/AFL without accompanying rhythm proof will suffice).
3. Documentation of continuous AF/AFL for ≥24 hours during the in-hospital stay for the index cardiac surgery.
4. Subjects who, at the discretion of the treating cardiac surgery team, would be treated and discharged with oral anticoagulation due to POAF/AFL.
5. Mechanical valve replacement.
6. Current or anticipated treatment with oral anticoagulation for indications other than AF/AFL.
7. Hospitalization for ≥10 days (for the index cardiac surgery, with day #0 being the day of surgery).
8. Planned discharge from hospital with a type IC or III anti-arrhythmic drug.
9. Having received >5 grams of IV and/or oral amiodarone during hospitalization for the index cardiac surgical procedure.
10. Women of childbearing potential (WOCBP).
11. History of percutaneous or surgical left atrial ablation for AF.
12. Presence of a cardiac implantable electronic device with a functioning atrial lead (pacemaker, implantable cardioverter defibrillator, or cardiac resynchronization device).
13. Presence of an implantable loop recorder.
14. History of left atrial appendage ligation, removal, or occlusion.
15. Subjects with known allergies or hypersensitivities to adhesives or hydrogel.
16. Inability to provide written informed consent.
17. Current or anticipated participation in another randomized controlled trial in which the interventional drug or device is known to affect the incidence of the primary or secondary outcomes of this study.