LAUSR

BACKGROUND Subcutaneous ICDs (S-ICDs) and leadless pacemakers (LPs) are intended to diminish transvenous lead-related complications. However, S-ICDs do not deliver antibradycardia or antitachycardia pacing (ATP) and currently, there is no commercially available coordinated leadless option for patients with defibrillator and (expected) pacing needs. OBJECTIVE We evaluated the performance, safety, and potential replacement strategies of a novel modular cardiac rhythm management (mCRM) system: a wirelessly communicating ATP-enabled LP and S-ICD in a preclinical model. METHODS LP implantation was attempted in 68 canine subjects and in 38 an S-ICD was implanted as well. Animals were evaluated serially for up to 18 months. At all evaluations, communication thresholds (CTs) between the devices, LP electrical parameters and system-related complications were assessed. Different replacement strategies were tested. RESULTS The LP was successfully implanted in 67/68 (98.5%) and the concomitant S-ICD in 38/38 (100%). mCRM communication was successful in 1022/1024 (99.8%) evaluations. Mean CT was 2.2±0.7V at implant and stable afterwards (18 months: 1.8±0.7V). In multivariable analysis, larger LP-to-S-ICD angle and dorsal posture were associated with higher CTs. At implant, mean pacing capture threshold (PCT), impedance and R-wave amplitude were 0.3±0.1V, 898.4±198.9Ω and 26.4±8.2mV. PCT remained stable and impedance and R-wave amplitudes were within acceptable ranges throughout (18 months: mean 0.7±0.4V, 619.1±90.6Ω, 20.1±8.4mV). Different replacement strategies seem feasible. CONCLUSION This first mCRM system demonstrated excellent performance up to 18 months in a preclinical model.