正向低频长脉冲对逆向刺激模拟胃异位起搏点诱发胃电过速的治疗作用

目的探讨正向低频长脉冲胃电刺激对逆向高频长脉冲模拟胃异位起搏点诱发胃电过速的治疗作用。方法7条纯种雌性比格犬，依次沿胃大弯前壁浆膜层植入4对心脏起搏电极。通过距离幽门最近的1对电极输入高频长脉冲电信号诱导内源性胃肌电活动发生胃电过速，刺激参数为0．3mA、300ms、9cpm。刺激10min后，通过距离口端最近的1对电极输入不同振幅的低频长脉冲，直至纠正胃电过速，从而获得正向控制胃电过速的最小能量。观察电刺激前、刺激中和刺激后消化不良症状并进行评分。结果正向低频长脉冲能够完全控制逆向高频长脉冲模拟异位起搏点诱发的胃电过速，最小刺激振幅为（5．0±0．93）mA，最小刺激能量为（1500±277．75）（ms×mA）。获得完全控制的正向低频长脉冲与逆向高频长脉冲相比，正常胃慢波百分率升高（95．61％±3．78％ vs42．68％±19．74％，P=0．001），胃电过速百分率降低（3．58％±0．85％ vs40．29％±19．68％，P=0．001），主频降低（6．35±0．66 vs5．60±0．85，P=0．031），主功升高（-9．67±5．08 vs-2．26±1．03，P=0．001）。胃慢波基线期、高频长脉冲（RG-ES）期、完全控制的低频长脉冲（FGES＋RGES）期的消化不良症状评分均为1分，无明显差异。结论正向低频长脉冲能够完全纠正由高频逆向长脉冲模拟人工 异位起搏点引发的胃电过速，并恢复由此降低的胃动力。

Forward long-pulse gastric electric stimulation at low frequency normalize artificial ectopic tachy-gastria induced by antral electrical stimulation

Objective To explore the minimum energy of forward long pulse gastric electric stimulation （GES） at low frequency to normalize artificial ectopic tachygastria induced by antral electrical stimulation. Methods Seven female beagles dogs chronically implanted with four pairs of cardiac pacing electrodes along the greater curvature of stomach into serosa were applied with retrograde gastric electrical simulation （RGES） and forward gastric electrical stimulation （FGES）. RGES performed via electrodes positioned in the distal part of antrum near pylorus, which included a series of fixed stimulating parameters ：9 cpm, 300 ms, 0.3 mA, was kept on applying to produce substantial tachygastria. In contrast to RGES, FGES was performed with long pulses via the electrodes around the region of corpus and its initially stimulating parameters was 5.5 cpm, 300 ms, 1 mA, the amplitude would be increased stepwise by 1 mA until tachyg- astria induced by RGES was completely normalized. During the whole period of modulation and application of long pul- ses FGES, long-pulse RGES was simultaneously conducted without any discontinuance. Gastric slow waves and animal dyspeptic symptoms were recorded. Results The minimum amplitude, （5.0 ± 0.93） mA and the minimum energy, （ 1 500 ± 277.75） mA ＊ ms of FGES could completely normalize artificial ectopic tachygastria induced by RGES. Compared with RGES, FGES makes the percentage of normal slow wave recover to normal （95.61% ± 3.78% vs 42.68% ± 19.74% ,P = 0. 001 ） , the percentage of tackygastria decrease （3.58% ± 0. 85% vs 40.29% ± 19.68% , P = 0. 001 ） , DF decrease （6.35 ±0.66 vs 5.60±0.85, P=0.031） and DP increase （ -9.67 ±5.08 vs -2.26 ± 1.03,P= 0. 001）. The score of dyspeptic symptoms either before or during RGES and FGES were 1 point. Conclusion FGES can normalize the artificial ectopic tachygastria induced by antral electrical stimulation as well as enhance the RGES-induced gastric hypomotility.