New-Onset Device-Detected Atrial Fibrillation in Patients With Atrial Floating Dipole Implantable Cardioverter-Defibrillators: A Propensity Score-Matched Comparison With Conventional Dual-Chamber Systems

Background: Device-detected subclinical atrial fibrillation (DDAF) is a significant risk factor for major cardiovascular events, especially in implantable cardioverter-defibrillator (ICD) recipients. The DX ICD, which utilizes a single ventricular lead with a floating atrial dipole, has demonstrated superior performance in diagnosing DDAF compared to conventional single-lead ICDs. However, comparisons between DX and dual-chamber (DDD) ICDs for atrial monitoring are limited. Objective: To compare the incidence of newly detected DDAF in patients without an indication for atrial pacing who received either a DX or a standard DDD ICD. Methods: Remote transmissions from the Italian Home Monitoring Expert Alliance dataset were analyzed. DDAF incidence for different burden cutoffs (≥ 15 min, ≥ 6 h, and ≥ 24 h) was compared between groups using propensity score (PS) matching to adjust for baseline characteristics. Results: In a cohort of 1329 patients (527 with DX ICD and 802 with DDD ICD), 30.7% experienced DDAF lasting ≥ 15 min, 22.3% ≥ 6 h, and 14.0% ≥ 24 h during a median follow-up of 4.5 years. DDAF incidence was lower in the DX ICD group for all burden cutoffs (p < 0.0001). However, after PS matching, DDAF rates were similar between groups, with no significant differences (p ≥ 0.36). Multivariate analysis identified age and 1-month right ventricular pacing percentage as predictors of DDAF across all burden cutoffs, with no effect based on device type or programmed basic rate. Conclusion: In patients without atrial pacing indication or history of clinical atrial fibrillation at implantation, the DX ICD demonstrated DDAF detection capabilities comparable to DDD ICDs in a real-world setting.