Buckley Una, Chui Ray W, Rajendran Pradeep S, Vrabec Tina, Shivkumar Kalyanam, Ardell Jeffrey L
University of California - Los Angeles (UCLA) Cardiac Arrhythmia Center, David Geffen School of Medicine, Los Angeles, California; UCLA Neurocardiology Research Center of Excellence, David Geffen School of Medicine, Los Angeles, California.
University of California - Los Angeles (UCLA) Cardiac Arrhythmia Center, David Geffen School of Medicine, Los Angeles, California; UCLA Neurocardiology Research Center of Excellence, David Geffen School of Medicine, Los Angeles, California; Molecular, Cellular, & Integrative Physiology Program, UCLA, Los Angeles, California.
Heart Rhythm. 2017 Jul;14(7):1063-1070. doi: 10.1016/j.hrthm.2017.02.020. Epub 2017 Feb 20.
Neuromodulation of the paravertebral ganglia by using symmetric voltage controlled kilohertz frequency alternating current (KHFAC) has the potential to be a reversible alternative to surgical intervention in patients with refractory ventricular arrhythmias. KHFAC creates scalable focal inhibition of action potential conduction.
The purpose of this article was to evaluate the efficacy of KHFAC when applied to the T1-T2 paravertebral chain to mitigate sympathetic outflow to the heart.
In anesthetized, vagotomized, porcine subjects, the heart was exposed via a midline sternotomy along with paravertebral chain ganglia. The T3 paravertebral ganglion was electrically stimulated, and activation recovery intervals (ARIs) were obtained from a 56-electrode sock placed over both ventricles. A bipolar Ag electrode was wrapped around the paravertebral chain between T1 and T2 and connected to a symmetric voltage controlled KHFAC generator. A comparison of cardiac indices during T3 stimulation conditions, with and without KHFAC, provided a measure of block efficacy.
Right-sided T3 stimulation (at 4 Hz) was titrated to produce reproducible ARI changes from baseline (52 ± 30 ms). KHFAC resulted in a 67% mitigation of T3 electrical stimulation effects on ARI (18.5 ± 22 ms; P < .005). T3 stimulation repeated after KHFAC produced equivalent ARI changes as control. KHFAC evoked a transient functional sympathoexcitation at onset that was inversely related to frequency and directly related to intensity. The optimum block threshold was 15 kHz and 15 V.
KHFAC applied to nexus (convergence) points of the cardiac nervous system produces a graded and reversible block of underlying axons. As such, KHFAC has the therapeutic potential for on-demand and reversible mitigation of sympathoexcitation.
使用对称电压控制的千赫兹频率交流电（KHFAC）对椎旁神经节进行神经调节，有可能成为难治性室性心律失常患者手术干预的一种可逆替代方法。KHFAC可对动作电位传导产生可扩展的局灶性抑制。
本文旨在评估将KHFAC应用于T1 - T2椎旁链以减轻心脏交感神经输出的疗效。
在麻醉、切断迷走神经的猪受试者中，通过正中胸骨切开术暴露心脏及椎旁链神经节。电刺激T3椎旁神经节，并从置于双心室的56电极套获取激活恢复间期（ARI）。一个双极银电极缠绕在T1和T2之间的椎旁链上，并连接到对称电压控制的KHFAC发生器。比较在有和没有KHFAC的T3刺激条件下的心脏指数，以衡量阻滞效果。
右侧T3刺激（4赫兹）经滴定可产生与基线相比可重复的ARI变化（52±30毫秒）。KHFAC使T3电刺激对ARI的影响减轻67%（18.5±22毫秒；P<.005）。KHFAC后重复T3刺激产生的ARI变化与对照相当。KHFAC在开始时诱发短暂的功能性交感神经兴奋，其与频率呈负相关，与强度呈正相关。最佳阻滞阈值为15千赫兹和15伏。
将KHFAC应用于心脏神经系统的连接（汇聚）点可产生对基础轴突的分级且可逆的阻滞。因此，KHFAC具有按需和可逆减轻交感神经兴奋的治疗潜力。
