Comparison of newly detected atrial high-rate episodes incidence in single-lead ICDs with a floating atrial dipole and dual-chamber ICDs: a propensity score-matched analysis from the HMEA project

Abstract Background Atrial high-rate episodes (AHREs) represent a significant risk for major adverse cardiovascular events with timely detection being crucial, particularly in high-risk patients as implantable cardioverter defibrillator (ICD) recipients. In this context, the use of a single ventricular ICD lead with a floating atrial dipole (DX-ICD, Biotronik SE & Co.) has been shown to be superior respect to conventional single-lead ICD. Nevertheless, the comparison between DX ICDs and dual-chamber ICDs for AHREs monitoring has been poorly investigated. Purpose To compare the incidence of newly detected AHREs in patients without an indication for atrial pacing who received either a DX-ICD or a standard dual-chamber ICD. Methods Patients without an history of atrial fibrillation or an indication for atrial pacing, who were implanted with either a DX ICD or DDD ICD across 52 centers, were selected from the Italian Home Monitoring Expert Alliance (HMEA) dataset. Comparison of AHREs incidence in both groups for different burden cutoffs (≥15 minutes, ≥6 hours, ≥24 hours) was assessed within the overall cohort and balancing baseline characteristics with the propensity score (PS) matching. Results In an overall population of 1,329 patients (527 with DX ICD and 802 with DDD ICD – Table 1), 30.7% experienced AHREs lasting ≥15 mins, 22.3% ≥6 hours, and 14% ≥24 hours, during a median follow-up of 4.5 years [IQR 2.8-6.8]. The incidence rates of AHREs were significantly lower in the DX ICD group respect to the DDD ICD group for all burden cutoffs (Figure). The 1:1 PS-matching identified a subset of 792 patients, with an absolute standardized mean difference <0.1 for all baseline variables. When analyzing the PS-matched cohort, the incidence rates of AHREs were similar between groups for each burden cutoff (≥15-min 6.4/100 patient-years vs. 7.3/100 patient-years, p=0.36; ≥6-hour 4.3/100 patient-years vs. 4.4/100 patient-years, p = 0.84; ≥24-hour 2.3/100 patient-years vs. 2.8/100 patient-years, p=0.36) (Figure). At multivariate analysis, age and 1-month right ventricle pacing were the only predictors of AHREs, with no effect depending of device type (DX-ICD vs. DDD-ICD) or programmed basic rate (Table 2). Conclusions In a real-world setting, the use of dual-chamber ICDs remains high among patients requiring defibrillator therapy with no atrial pacing indication. In these patients, the DX ICD system with an atrial floating dipole showed AHREs detection capabilities comparable to dual-chamber devices with an implanted atrial lead.Figure:Kaplan-Meier curves