Baseline and decline in device-derived activity level predict risk of death and heart failure in patients with an ICD for primary prevention.

Background: Implanted defibrillators are capable of recording activity data based on company-specific proprietary algorithms. This study aimed to determine the prognostic significance of baseline and decline in device-derived activity level across different device companies in the real world.

Methods: We performed a retrospective cohort study of patients (n = 280) who underwent a defibrillator implantation (Boston, Medtronic, St.