Fetter J, Bobeldyk G L, Engman F J
Pacing Clin Electrophysiol. 1984 Sep;7(5):871-81. doi: 10.1111/j.1540-8159.1984.tb05630.x.
Myopotential oversensing by unipolar pulse generators can cause patient symptoms ranging from dizziness and syncope to ventricular tachycardia. Seventy-seven patients with implanted unipolar pacemakers from three manufacturers participated in isometric and reach exercises to evaluate their pacemakers' susceptibility to myopotentials. Myopotential inhibition occurred in 47% of the patients performing the reach maneuver. Testing revealed a wide difference in level of susceptibility to myopotentials between pacemakers of different manufacture (a low of 33% inhibition for the least susceptible to a high of 78% inhibition for the most susceptible during the reach maneuver). The normal pacing interval was extended by myopotential oversensing for each manufacturer's model within a range of 0.3-3.9 seconds. Pulse generators incorporating additional automatically-adjusting threshold and reversion circuits in the sense amplifier along with standard bandpass filtering exhibited: a) two-to-three times less susceptibility to myopotentials; and b) a 75% reduction in the maximum pacing interval extension as compared with pacemakers with bandpass filtering alone. The effectiveness of insulative coating in reducing myopotential inhibition was substantiated as coated pulse generators had a 22% lower incidence of muscle sensing than those that were uncoated. Six out of seven patients tested had symptoms during Holter monitoring which correlated with pacemaker myopotential inhibition. Selecting pulse generators with improved sensing amplifiers, clinical testing of patients with unipolar pacemakers using the reach method, and reprogramming of sensitivity will significantly reduce the incidence of myopotential inhibition.
单极脉冲发生器对肌电位的过度感知可导致患者出现从头晕、晕厥到室性心动过速等一系列症状。来自三家制造商的77名植入单极起搏器的患者参与了等长运动和伸展运动，以评估其起搏器对肌电位的易感性。在进行伸展动作的患者中，有47%发生了肌电位抑制。测试显示，不同制造商生产的起搏器对肌电位的易感性水平存在很大差异（在伸展动作期间，最不易感的起搏器抑制率低至33%，最易感的高达78%）。对于每个制造商的型号，正常起搏间期因肌电位过度感知而延长，延长范围为0.3 - 3.9秒。在传感放大器中集成了额外的自动调整阈值和反转电路以及标准带通滤波的脉冲发生器表现出：a）对肌电位的易感性降低了两到三倍；b）与仅具有带通滤波的起搏器相比，最大起搏间期延长减少了75%。绝缘涂层在减少肌电位抑制方面的有效性得到了证实，因为涂覆的脉冲发生器肌肉感知发生率比未涂覆的低22%。在动态心电图监测期间，接受测试的7名患者中有6名出现了与起搏器肌电位抑制相关的症状。选择具有改进传感放大器的脉冲发生器、使用伸展方法对单极起搏器患者进行临床测试以及重新编程灵敏度，将显著降低肌电位抑制的发生率。
