Despite a clear definition in the European Society of Cardiology (ESC) guidelines, the differentiation between paroxysmal (self-terminating) and persistent (nonself- terminating) atrial fibrillation (AF) remains challenging in clinical practice. Some patients with presumed persistent AF are planned for electrical cardioversion (ECV) but appear to have a paroxysmal pattern or present in sinus rhythm (SR) at the scheduled ECV appointment. This results in unnecessary visits or interventions for patients, and costs and burden for the hospitals and health insurances. Based on the feasibility of the TeleCheck-AF approach, which is an on-demand mobile health (mHealth) infrastructure incorporating app-based heart rate and rhythm monitoring to support remote AF management through teleconsultation, the investigators aim to extend this mHealth approach to the management of presumed persistent AF patients planned for ECV.

When putted on the waiting list for ECV (at baseline), the case-coordinator (investigator or nurse) will contact the patient and provide an mHealthprescription, manual and app-activation QR-code to use the CE-marked mobile phone app using photoplethysmography (PPG) technology through the built-in mobile phone's camera to monitor rate and rhythm. After 24-hours the case-coordinator will check whether the patient activated the app, otherwise will contact patient for further support.

Recordings from the device will be sent to a secure cloud application. This cloud application is equipped with an automatic analyses algorithm with a red-amber-green alert system. Patients will be asked to use the app 3-times a day and in case of symptom onset and disappearance while being on the waiting list for ECV. In case of amber alert (recording in asystole > 5 sec, tachycardia > 170 bpm, bradycardia 110 bpm) the subject's care team will be notified of the alert by the investigators within one workday. The subject will then be contacted by the care team to intensify rate control if necessary. Subjects also have the possibility to contact the investigators directly if needed. In case of green alert (SR recording), the investigators will process the alert within one workweek. The subject will then be contacted by the investigators to visit the hospital and execute a 12-lead ECG to confirm SR as soon as possible. When SR is confirmed by ECG, scheduled ECV will be cancelled by the treating physician and rate/rhythm control medication might be intensified, this is part of standard care. When SR is not confirmed by ECG, treatment decisions will remain to the treating physician and he/she will decide whether or not to cancel scheduled ECV (based on PPG recordings). In the 4-weeks following scheduled ECV appointment, all patients will receive remote semi-continuous app-based rate/rhythm monitoring including red-amber- green alert notifications and will be asked to use the app 3-times a day and in case of symptom onset and disappearance. In case of an amber alert, the subject's care team will be notified of the alert by the investigators within one workday. The subject will then be contacted by the care team to intensify rate control if necessary. Subjects also have the possibility to contact the investigators directly if needed. Of importance is that alerts will only be assessed by the investigators during office hours. Patients will specifically (both verbally and written) be informed that in case of alarming symptoms during or outside of office hours, emergency services or their own general practitioner should be contacted. In all cases of acute emergencies, a patient should contact the emergency services. Furthermore, patients will be asked to fulfill a self-composed questionnaire based on the System Usability Scale extended with additional questions to assess the usability and user-friendliness of the refined TeleCheck-AF approach around ECV at 4-week follow-up. Also a self-composed questionnaire based on the HADS-A scale will be used to assess anxiety while using the mHealth-based refined TeleCheck-AF approach around ECV at four weeks.

Inclusion Criteria:

• Presumed persistent AF
• Scheduled for ECV
• Age ≥18 years
• Smartphone possession
• Ability and willing to sign informed consent
• Ability and willing to use mobile phone app (FibriCheck)

Exclusion Criteria:

• Deemed unsuitable for participation by attending physician
• Presence of an active implanted electronic cardiac device

Patients with presumed persistent AF, age ≥18 years, scheduled for ECV, and in possession of a smartphone will be included in this study from January 2022 to January 2024.