Single- vs dual-chamber ICDs to prevent from inappropriate shocks: the debate is still alive

Abstract

Abstract Background The efficacy of dual-chamber implantable cardioverter defibrillators (ICDs) in preventing from inappropriate shocks (IS) is still a matter of debate. Purpose To compare the risk of IS among single- and dual-chamber ICDs in a cohort of heart failure (HF) patients carrying a prophylactic device. We aimed to focus on the relationship between programming and discriminators, and the risk of IS in a large cohort. Methods All HF patients with left ventricle ejection fraction <35% undergoing a prophylactic ICD-only implant were collected from the multicentre, prospective and nationwide UMBRELLA study. ICD programming was performed according to regular clinical practice at each site and. ICD setting and arrhythmic events occurring during the study period were automatically stored through the remote monitoring system. An experts committee analysed in a blinded manner all electrograms coming from the arrhythmic events. Results From 2006 to 2015, 782 patients implanted with an ICD were analysed (537 patients (68.7%) with single-chamber ICDs and 245 patients (31.3%) with dual-chamber ICDs). During a mean follow-up of 4.35±2 years, 109 IS were delivered in 49 patients. IS occurred in 7.8% (n=42) of patients carrying single-chamber ICDs and in 2.9% (n=7) of dual-chamber carriers (p=0.001). A propensity score matched analysis was performed. The matched cohort was composed by 110 well-balanced (regarding baseline characteristics and programming) patients. In the weighted sample, dual-chamber ICDs were related to lower rates of IS (Figure 1) as compared to single-chamber devices (0.9% vs. 11.8%, p≤0.001). Among programming the following ICD settings correlated to lower risk of IS: ≥30 of 40 intervals detection within ventricular fibrillation (VF) zone (HR=0.47; p=0.018), a programmed ATP-capable zone enabled through VF zone (HR=0.54; p=0.038), morphology discriminator (Wavelet®) (HR=0.42; p=0.032), and the specific dual-chamber discriminator (PR Logic®) (HR=0.28; p=0.004). After multivariable Cox regression analysis including clinical variables and device settings, PR Logic® discriminator was the only programming parameter independently related to a lower risk of IS (HR=0.18, CI 0.06–0.48, p=0.001). Conclusions In our nationwide cohort of primary prevention ICD-only patients, dual-chamber devices were associated with a lower risk of IS. ICDs equipped with PR Logic® discriminator might be useful to prevent from IS. Funding Acknowledgement Type of funding sources: None. Programming in the matched populationFigure 1