Atrial Fibrillation detection by a subcutaneous monitoring device

The Reveal XT subcutaneous insertable cardiac monitor detects Atrial Fibrillation (AF) from the irregularity of the ventricular rhythm. This study is a first assessment of the AF detection performance using subcutaneous signals from implanted devices. Patients implanted with a Reveal XT device were monitored by a dedicated Holter system, recording the surface ECG and uplinked device data. Device detections of AF were reconstructed from the uplinked data and classified as either true positive, false positive and false negative using the surface ECG for reference. In a total of 82 Holter recordings from 60 patients, the mean AF episode detection sensitivity was 90.6% and 98.1% for AF episodes ≥ 2 minutes and ≥ 4 minutes, respectively. The mean episode PPV was 55.1%. False positive detections were clustered within a few patients with irregular rhythms that were not annotated as AF.