消融Marshall韧带远段对急性心力衰竭犬心功能和室性心律失常的影响

Effects of ablation of Marshall ligament distal segment on cardiac function and ventricular arrhythmia in canines with acute heart failure

目的本研究拟在探讨消融Marshall韧带(LOM)远段和对急性心力衰竭(简称心衰)犬心功能及室性心律失常的影响。方法17只成年健康雄性犬随机分为2组:对照组(n=9),LOM消融组(n=8)。消融组开胸后进行LOM远段消融,对照组实施假消融。然后将多极电极分别缝于左右心室,采用持续快速心室起搏6 h(VP-6 h)构建急性心衰模型。两组分别记录心电图,分析基础状态、VP-6 h心率变异性,包括低频(LF)、高频(HF)、LF/HF值。分别于基础状态和VP-6 h经股静脉采集外周血,检测血清去甲肾上腺素(NE)水平,并于基础状态和VP-6 h分别通过彩色超声心动图测量心功能指标。基础状态下和VP-6 h分别测量左右心室有效不应期(ERP),记录测量ERP过程中S1S2刺激诱发室性心律失常事件,最后采用S1S1刺激法测定心室颤动阈值。结果对照组有1例死亡。与基础状态相比,对照组VP-6 h LF值[(63.09±12.11)nu vs(49.09±4.67)nu,P<0.05]和LF/HF值(2.16±1.12 vs 1.10±0.15,P<0.05)均升高,消融组VP-6 h较对照组同时刻LF值[(34.20±11.80)nu vs(63.09±12.11)nu,P<0.05]和LF/HF值(0.64±0.24 vs 2.16±1.12,P<0.05)均降低。对照组VP-6 h血清NE水平较基础状态升高[(2.5±0.2)ng/ml vs(1.1±0.13)ng/ml,P<0.05],与对照组同时刻比较,消融组VP-6 h血清NE水平降低[(1.3±0.1)ng/ml vs(2.5±0.2)ng/ml,P<0.05]。消融组VP-6 h左室射血分数值高于对照组(0.44±0.02 vs 0.40±0.02,P<0.05)。对照组VP-6 h ERP较基础状态时心室各位点均有缩短(P<0.05),而消融组VP-6 h ERP较对照组同时刻心室各位点ERP均延长(P<0.05)。消融组在心室起搏结束后记录到的单发室性早搏少于对照组[3(0.75,5)vs 11.5(6.25,17),P<0.05]。消融组较对照组心室颤动阈值增高[(139±31.37)ms vs(195±39.64)ms,P<0.05]。结论消融LOM远段可改善急性心衰犬心功能并改善心室电生理重构、降低心室颤动易感性,这种作用的潜在机制可能与降低交感神经活性有关。

Objective To investigate the effect of ablation of ligament of Marshall(LOM)on cardiac function and ventricular arrhythmia in acute heart failure canines.Methods Seventeen healthy adult male dogs were randomly divided into two groups:the control group(n=9)and the LOM ablation group(n=8).The ablation group underwent LOM ablation after thoracotomy,while the control group underwent sham ablation.Then,the multi-electrode electrodes were sewn into the left and right ventricles respectively,and the acute heart failure model was constructed by continuous rapid ventricular pacing for 6h(VP-6h).Electrocardiograms were recorded in the two groups,and basic status and VP-6hheart rate variability were analyzed,including low frequency(LF),high frequency(HF)and LF/HF values.Peripheral blood was collected from the femoral vein at basal state and VP-6h,respectively,for detecting the level of serum norepinephrine(NE).The indicators of cardiac function were measured by echocardiography at basal state and VP-6h,respectively.Effective refractory period(ERP)of left and right ventricles was measured in the basal state and VP-6hrespectively,stimulation were recorded.Finally,ventricular fibrillation with the basic state,VP-6hLF value[(63.09±12.11)nu vs(49.09±4.67)nu,P<0.05]and LF/HF value(2.16±1.12vs 1.10±0.15,P<0.05)in the control group increased,and VP-6hLF value[(34.20±11.80)nu vs(63.09±12.11)nu,P<0.05]and LF/HF value(0.64±0.24vs 2.16±1.12,P<0.05)in the ablation group decreased compared with that in the control group at the same state.The serum NE level of VP-6hin the control group was higher than that of the basal state[(2.5±0.2)ng/ml vs(1.1±0.13)ng/ml,P<0.05],and the serum NE level of VP-6hin the ablation group was lower than that of the control group at the same time[(1.3±0.1)ng/ml vs(2.5±0.2)ng/ml,P<0.05].The VP-6hleft ventricular ejection fraction value of ablation group was higher than that of control group(0.44±0.02vs 0.40±0.02,P<0.05).VP-6hERP in the control group was shorter than that in the basic state(P<0.05),while VP-6hERP in the ablation group was longer than that in the control group(P<0.05).The ablation group recorded fewer single premature ventricular beats after ventricular pacing than the control group[3(0.75,5)vs11.5(6.25,17),P<0.05].The threshold of ventricular fibrillation was higher in the ablation group than in the control group[(139±31.37)ms vs(195±39.64)ms,P<0.05].Conclusion Ablation of the distal segment of LOM can improve cardiac function and improve ventricular electrophysiological remodeling and reduce susceptibility to ventricular fibrillation in dogs with acute heart failure.The underlying mechanism of this effect may be related to decreased sympathetic activity.[Chinese Journal of Cardiac Pacing and Electrophysiology,2020,34(2):140-144]