Purpose: Atrial fibrillation (AF) is a common arrhythmia in patients wearing implantable cardiac devices. AF has been associated with higher risk of stroke, but, when asymptomatic and intermittent, it may remain clinically unknown, thus reducing the chances of implementing stroke prevention strategies, like oral anticoagulation therapy (OAC). Aim of our project was to measure the clinical and organizational value of a web-based application, the AFinder, in improving AF detection and OAC management in patients wearing implantable pacemakers or defibrillators. Methods: 7 Italian cardiological centres prospectively followed 472 patients via in-hospital and remote visits from January 2011 to November 2012. Remote monitoring was performed by expert nurses and cardiologists who reviewed device data transmitted via patient monitors and classified clinically relevant events as AF occurrence. A new web-based application, AFinder, was exploited to identify patients with AF through a systematic scan of device data transmitted via remote monitors. To evaluate the clinical and organizational value of AFinder, we compared the number of patients found in AF during the observation period by the remote monitoring and by AFinder application and counted the number of patients in whom the OAC therapy was implemented as a consequence of new AF documentation. Results: 472 patients (76% male, 69±10 years old) were included; 184 (39%) had AF history with a mean CHADS2 score ≥2; 208 (44%) were on OAC. During a mean remote monitoring period of 12±8 months, AF occurred in 159/472 (34%) patients, in particular 58/109 pacemaker patients and 101/363 ICD patients. AFinder application found AF also in 54 patients who were not identified as AF patients during the remote monitoring observation. Out of these 54 patients, 15 had AF history as documented by patient medical records and were already treated by OAC, 6 patients were on OAC because they had valvular prostheses or suffered thromboembolic complications, while, importantly, 33 patients had no previous history of AF and were therefore not protected by OAC; in 22/33 patients AF was not considered clinically relevant due to short duration – less than 1 hour in most patients – while OAC therapy was proposed to 11/33 patients who were considered to have clinically relevant AF and high stroke risk. Conclusions: AF is a frequent comorbidity in both pacemaker and ICD patients. AFinder application enabled us to discover additional AF patients, as compared with standard remote monitoring and to improve OAC use in accordance with available guidelines for stroke risk reduction.