Improving atrial fibrillation or flutter detection and management by smartphone-based photoplethysmography rhythm monitoring following cardiac surgery: a pragmatic randomized trial

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  Figure 1. Study protocol. Patients were randomly assigned in a 1:1 ratio to the monitoring group (PPG measurements three times daily and while perceiving symptoms of AF) or to usual care with no mandated monitoring. Patients randomized to the monitoring group were instructed to commence the PPG measurements on the day of discharge from the hospital and to continue until the follow-up visit with their cardiologist or cardiac surgeon, scheduled at 6 weeks after discharge (allowed from 21 to 91 days after discharge). In case of AF or AFL detection with PPG, the patient was instructed to visit a physician. Early follow-up was either performed by the patient’s general practitioner, cardiologist, or cardiac surgeon or at the emergency department. Patients randomized to the usual care group did not undergo any protocol-mandated rhythm monitoring after randomization. AF, atrial fibrillation; AFL, atrial flutter; ED, emergency department, GP, general practitioner; PPG, photoplethysmography.

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  Figure 2. Study flowchart.

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  Figure 3. Kaplan–Meier curves showing the cumulative incidence of the primary and secondary outcome for the monitoring and usual care groups. Kaplan–Meier estimates for the cumulative incidence of (A) the primary outcome, which is a composite endpoint driven by initiation of OAF therapy and rhythm control intervention, and (B) AF or AFL detection in the monitoring group (blue) and in the usual care group (red). AF, atrial fibrillation; AFL, atrial flutter.

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  Figure 4. Primary and secondary outcomes by intent-to-treat analysis. Odds ratio for the primary outcome was calculated with GEE logistic regression. Odds ratios of components of the primary outcome and secondary outcomes were calculated with binary logistic regression. AF or AFL were detected with PPG or ECG technology. *Odds ratios could not be calculated because 0 events occurred in one group or both groups. AF, atrial fibrillation; AFL, atrial flutter.