Departments of Cardiovascular Medicine and Molecular Cardiology, Cleveland Clinic, OH; and New York Institute of Technology College of Osteopathic Medicine, Old Westbury.
Circ Heart Fail. 2014 Mar 1;7(2):320-6. doi: 10.1161/CIRCHEARTFAILURE.113.000937. Epub 2014 Jan 7.
Cervical vagal nerve stimulation (VNS) can improve left ventricular dysfunction in the setting of heart failure (HF). However, little is known about the impact of VNS on left atrial (LA) function. The aim of this study was to compare LA mechanics and histology between control and VNS-treated animals during HF development.
Fifteen mongrel dogs were randomized into control (n=7) and VNS (n=8) groups. All dogs underwent 8 weeks of high-rate ventricular pacing (at 220 beats per minute for the first 4 weeks to develop HF and another 4 weeks at 180 beats per minute to maintain HF). LA contractile function (LA negative peak strain), conduit function (LA positive peak strain), and reservoir function (LA total strain) were measured from speckle tracking in 2 groups. At the end of the terminal study, the LA appendage was obtained. Baseline LA strains were comparable in the control and VNS-treated dogs. At 4 and 8 weeks of ventricular pacing, all LA strains were decreased and LA volumes were increased in the control group compared with the VNS group (P<0.05). Histological evaluation of the left atrium revealed that percent fibrosis was significantly lower in the VNS versus the control group (8±1% versus 13±1%; P<0.001). Finally, transmitral flow showed decreased atrial contribution to left ventricular filling in the control group (P<0.05).
VNS improved LA function and volumes and suppressed LA fibrosis in the canine high-rate ventricular pacing model. VNS is a novel and potentially useful therapy for improving LA function during HF.
颈迷走神经刺激（VNS）可改善心力衰竭（HF）患者左心室功能障碍。然而，关于 VNS 对左心房（LA）功能的影响知之甚少。本研究旨在比较 HF 发展过程中对照组和 VNS 治疗组动物的 LA 力学和组织学。
15 只杂种犬随机分为对照组（n=7）和 VNS 组（n=8）。所有犬均接受 8 周的高心率心室起搏（前 4 周以 220 次/分钟起搏以发展 HF，然后以 180 次/分钟起搏 4 周以维持 HF）。2 组均采用斑点追踪法测量 LA 收缩功能（LA 负向峰值应变）、输送功能（LA 正向峰值应变）和储备功能（LA 总应变）。在终端研究结束时，获取 LA 附件。对照组和 VNS 治疗组的 LA 基线应变相当。与 VNS 组相比，对照组在 4 周和 8 周的心室起搏时，所有 LA 应变均降低，LA 容积均增加（P<0.05）。左心房的组织学评估显示，VNS 组的纤维化百分比明显低于对照组（8±1%对 13±1%；P<0.001）。最后，经二尖瓣血流显示对照组左心室充盈的心房贡献减少（P<0.05）。
VNS 改善了犬高心率心室起搏模型的 LA 功能和容积，并抑制了 LA 纤维化。VNS 是一种改善 HF 期间 LA 功能的新型且有潜在用途的治疗方法。
