Head-to-Head Comparison of Single- Versus Dual-Chamber ICD Discriminators for Tachyarrhythmia Detection: A Single-Manufacturer, Remote Monitoring-Based Bicentric Study

Background: Modern implantable cardioverter-defibrillators (ICDs) utilize single-chamber (SC) or dual-chamber (DC) discrimination algorithms to differentiate between tachyarrhythmias and minimize the risk of inappropriate therapies. While modern SC algorithms, especially those with morphology detection, are considered comparable to DC algorithms, the available data are limited. We aimed to compare the efficacy of SC and DC discrimination algorithms in malignant tachyarrhythmias. Methods: We retrospectively analyzed data from all patients with ICDs from a single manufacturer (Biotronik, Berlin, Germany) who were remotely monitored and followed up at two tertiary centers. Patients were divided into SC and DC groups, based on the programmed discrimination algorithm. The primary outcome was the risk of inappropriate therapies comparing SC vs. DC discriminators. A sensitivity analysis was also conducted, including only a subgroup of SC patients with active morphology discrimination. Results: A total of 557 patients were included. The distribution of the implanted ICDs was as follows: 76 VVI; 226 VDD; 76 DDD; and 179 CRT-D devices. A total of 124 ICDs were programmed utilizing SC and 433 were programmed into the DC discriminators group. Among the SC group, 47 (39%) ICDs used active morphology discrimination. The incidence of inappropriate ICD therapies did not differ among the SC and DC discrimination groups (Hazard Ratio [HR] 1.165; 95% Confidence Interval [CI] 0.393–3.448; p = 0.783). The predefined sensitivity analysis did not reveal any significant difference regarding this outcome (HR 1.809; 95% CI 0.241–13.577; p = 0.564). Conclusions: In this bicentric, remote monitoring-based study, the risk of inappropriate therapy in the SC group was similar to that of the DC group. Based on our results, SC discrimination is a suitable option, even for patients with dual-chamber devices.