Evaluation of the effectiveness of a wearable cardioverter defibrillator detection algorithm.

Abstract Background Wearable cardioverter defibrillators (WCDs) provide protection from sudden cardiac death. The efficacy of a WCD detection algorithm has not been reported outside of clinical trial. Methods The efficacy of the algorithm was reviewed through a retrospective analysis of appropriate shocks, inappropriate shocks, and arrhythmia detections during a 1-year period. Results WCD patients had an appropriate shock rate of 1.58 per 100 patient-months and an inappropriate shock rate of 0.99 per 100 patient-months. Most of the arrhythmia detections in a 3-month period were short in length, with only 2.7% of the detections lasting over 25 seconds, the time at which a shock becomes possible. Conclusions By incorporating a patient responsiveness test, as well as features that eliminate or reduce signal interference common to external electrocardiogram electrodes, the WCD detection algorithm has a low risk of inappropriate shocks.