This is a prospective multicenter clinical study comparing the efficacy of the Apple Watch AFib History tool to the iRhythm Zio Patch monitoring device in quantifying atrial fibrillation (AF) burden after surgical ablation. Patients with AF and mitral valve (MV) disease who undergo a Cox-Maze IV procedure concomitant to MV surgery will be evaluated at serial timepoints for up to 1 year postoperatively. The trial will be conducted in the United States at the Cleveland Clinic in Cleveland, OH and at the Washington University School of Medicine in St. Louis, MO.

The primary aim of this study is to evaluate the accuracy of current wearable technology using the Apple Watch AFib History tool, relative to ambulatory electrocardiogram (ECG) monitoring using the Zio Patch, for quantifying AF burden after surgical ablation. AF burden will be measured as a weekly estimate, defined as the percentage of time in AF over the prior seven consecutive days. This assessment will occur at 3 months, 6 months, and 1 year postoperatively.

This is a paired study design in which each subject will receive both the investigational device (Apple Watch) and reference device (Zio Patch) concurrently. The study population includes adults over the age of 22 years with a documented history of AF and MV disease undergoing elective MV surgery with concomitant Cox-Maze IV surgical ablation. All participants must be able to provide informed consent and adhere to the study follow-up schedule. Participants who meet the eligibility criteria will be enrolled on a rolling basis. Pre-surgical questionnaires, including Patient-Reported Outcomes Measurement Information System (PROMIS-10), MacNew, and Atrial Fibrillation Severity Scale (AFSS) surveys will be implemented at baseline and serial follow-up.

The monitoring period will be conducted in phases during serial follow-up at 1 month, 3 months, 6 months, and 1 year postoperatively. The Apple Watch will be worn postoperatively for the study duration. Participants will be instructed to charge the device overnight. The Zio Patch 14-day ambulatory ECG monitor will be applied at the following study timepoints: 3 months, 6 months, and 1 year postoperatively. Participants will be instructed to wear the Apple Watch concurrently during Zio Patch monitoring periods, as well as in the interval between visits.

At each follow-up visit (1 month, 3 months, 6 months, and 1 year), participants will undergo standardized evaluations, including a physical exam and the administration of the same standardized questionnaires. Comparative data from the Apple Watch and Zio Patch will be analyzed at the 3 months, 6 months, and 1 year visits.

Inclusion Criteria:

• 22 years of age or older
• Documented or current history of atrial fibrillation (paroxysmal, persistent, or long-standing persistent)
• Undergoing elective mitral valve surgery (repair or replacement) with concomitant surgical ablation using a Cox-Maze IV lesion set and left atrial appendage occlusion procedure, with and without concomitant tricuspid valve procedure (repair or replacement)
• Use or access to Apple iPhone
• Willing and able to provide informed consent and wear both the Apple Watch and Zio Patch at pre-specified intervals for the duration of the study period
• Willing and able to participate in long-term follow up including study visits and surveys

Exclusion Criteria:

• Presence of a cardiac pacemaker
• Heart failure with reduced ejection fraction (<40%)
• Concomitant aortic valve replacement or coronary artery bypass graft
• Personal or family history of adhesive skin allergies to adhesives or hydrogels
• Tattoos located on the skin of the wrist or forearm where the Apple Watch will be placed
• Pregnancy

Adult patients (>22 years) with a documented history of atrial fibrillation and mitral valve disease who undergo surgical ablation with a Cox-Maze IV concomitant to elective mitral valve surgery.