Feasibility of novel atrial mechanical sensing method for leadless atrioventricular synchronous pacing

FUNDING ACKNOWLEDGEMENTS: Type of funding sources: None. BACKGROUND/INTRODUCTION: A novel leadless pacemaker enables atrioventricular synchronous pacing. However, there have been still difficulties to obtain high atrioventricular (AV) synchrony due to a mechanical sensing algorithm. We’ve reported a new sensing method for acquiring high AV synchrony regardless of heart rate. Our hypothesis is that this novel sensing method might facilitate better AV synchrony. PURPOSE: The purpose of this study is to investigate the feasibility of our novel sensing method for the patients that ventricular activity completely depends on the ventricular pacing. METHODS: This study is a retrospective study conducted by 2 centers. From the 1st December, 2021 to the 31th October, 2022, leadless pacemakers with atrioventricular synchronous pacing were implanted to 32 patients in 2 centers. Among the 20 patients with sinus rhythm and complete AV block were analyzed. Two groups were compared in this study. Novel sensing setting was programmed during the hospitalization in Group 1, composed by 9 patients. Auto A3 threshold and auto A3 window end are turned off. An intentionally prolonged A3 window end and a low A3 threshold are programmed in a novel sensing method. Conventional setting (auto A3 threshold, auto A3 window end and auto A4 threshold were turned on) was programmed during the hospitalization in Group 2, composed by 11 patients. Device check was performed at the first outpatient clinic within 3 months after the implantation. RESULTS: Overall, 20 patients were analyzed. Baseline characters are described in Table 1. BMI (23.5±0.9 vs 20.4±0.8, p<0.05), BNP at the hospitalization (130.7±143.6 pg/ml vs 686.9±129.9 pg/ml, p<0.05) were different between 2 groups. Mean age, sex, past history of atrial fibrillation, hypertension, diabetes mellitus, dyslipidemia, past history of coronary artery disease, eGFR, previous cardiac surgery, left ventricular ejection fraction, E/A, left atrial diameter were no significant differences between 2 groups. Table 2 shows the comparison of the device parameters between 2 groups. In Group 1, AV synchrony (%AMVp) was significantly higher at the first outpatient clinic (81.0 ± 4.2 % vs 63.0 ± 5.7 %, p=0.03). A3 window end was significantly longer in Group 1 (883.3 ± 34.0 ms vs 757.0 ± 45.5 ms, p<0.05). A3 threshold was significantly lower in Group 1 (2.3 ± 0.5 m/s² vs 5.9 ± 0.7 m/s², p<0.05). There were no significant differences about A4 amplitude (1.8 ± 0.4 m/s² vs 1.0 ± 0.6 m/s², p=0.34) and A4 threshold (2.3 ± 0.3 m/s² vs 1.5 ± 0.4 m/s², p=0.12). CONCLUSION: Novel sensing method might be a feasible sensing method to obtain higher AV synchrony than conventional algorithm. Further prospective studies will be required. [Figure: see text] [Figure: see text]