Delay optimization of multipoint pacing increases the cardiac index and narrows the QRS width.

INTRODUCTION: The benefits of MPP delay optimization on hemodynamics and ventricular contraction synchronicity can be quantified with cardiac index (CI) and QRS width. A delay with the maximum CI and minimum QRS width may be the optimized settings for multipoint pacing (MPP). METHODS: Twelve patients with advanced heart failure who received cardiac resynchronization therapy defibrillation with MPP at the Third People's Hospital of Chengdu from March 2016 to April 2019 were included. Interventricular and intraventricular delays were optimized through noninvasive cardiac output monitoring and a 12 lead ECG. RESULTS: According to CI, the optimized left ventricular- left ventricular - right ventricular delay setting was mainly 25 ms-25 ms and 40 ms-40 ms. And the delay with the minimum QRS width was mainly in 5 ms-5 ms, 25 ms-25 ms, and 40 ms-25 ms. The optimal MPP configuration increased CI compared to the MPP setting that produced the minimum CI (4.5 ± 1.3 vs. 2.8 ± 1.0 L/min/m2, P < 0.001). The QRS width of the optimized MPP was narrower than the MPP setting that produced the maximum QRS width (127 ± 20 vs. 160 ± 29 ms, P < 0.001). CONCLUSION: Delay optimization improves hemodynamic response and ventricular contraction synchronicity. The delay of 25 ms-25 ms may be the optimal setting for most MPP patients.

[Safety and efficiency of pacing at right ventricular outflow versus at ventricular cardiac apex].

OBJECTIVE: To compare the safety and efficiency of pacing at right ventricular outflow versus right ventricular apex. METHOD: Patients were divided into two groups: pacing at ventricular cardiac apex (common pacing group, n = 22) and pacing at right ventricular outflow tract (uncommon pacing group, n = 18). RESULTS: Impedance and amplitude of R-wave were similar during implantation between the two groups (all P > 0.05). The pacing threshold and electric current were significant higher in uncommon group than those in common pacing group (all P < 0.05), however, these differences disappeared at 1 month post pacemaker implantation (all P > 0.05). The mean QRS duration tended to be shorter in uncommon pacing group compared to that in common pacing group (P > 0.05). There was no pacemaker associated adverse effect in both groups. CONCLUSION: The safety and efficiency of pacing at right ventricular outflow was similar as those of pacing at right ventricular apex.