Ramsdale D R, Charles R G
Pacing Clin Electrophysiol. 1985 May;8(3 Pt 1):378-86. doi: 10.1111/j.1540-8159.1985.tb05775.x.
Eighteen patients (11 men and 7 women) with symptomatic second or third degree atrioventricular block underwent implantation of the rate-responsive RS4-SRT pacing system. Exercise tolerance in RS4 mode was compared to that in VVI mode by randomized double-blind treadmill stress testing. Following hospital discharge, RS4 function was assessed by repeat exercise testing and 24-hour Holter monitoring. Difficulty in obtaining satisfactory P-wave amplitudes at implantation (mean 3.1 +/- 1.5 mV) resulted in prolonged implantation times (mean 79.4 +/- 26.4 minutes). Following implantation, 10 patients (58%) showed a significant ventricular rate response to exercise, seven did not, and one remained in sinus rhythm. For responders, peak ventricular paced rate and double product were significantly greater in RS4 than in VVI mode, being 101.8 +/- 5.8 vs. 74.3 +/- 0.4 beats per minute and 20.1 +/- 2.9 vs. 15.5 +/- 3.7 beats per minute X mmHg X 10(-3), respectively (p less than 0.001). However, treadmill times (10.5 +/- 2.6 vs. 9.7 +/- 3.3 minutes) and work done (5.51 +/- 2.01 vs. 4.97 +/- 2.33 joules X 10(-5] were not significantly different (p = 0.22). Following hospital discharge, repeat exercise testing and 24-hour Holter monitoring demonstrated RS4 function in 11 of 16 and 15 of 18 patients, respectively. We conclude that, due to unreliable atrial sensing, the RS4-SRT pacing system does not provide the reliable rate-responsiveness required to improve exercise tolerance.
18例有症状的二度或三度房室传导阻滞患者（11例男性，7例女性）接受了频率应答式RS4-SRT起搏系统植入术。通过随机双盲平板运动试验，比较了RS4模式和VVI模式下的运动耐量。出院后，通过重复运动试验和24小时动态心电图监测评估RS4功能。植入时获得满意P波振幅困难（平均3.1±1.5mV）导致植入时间延长（平均79.4±26.4分钟）。植入后，10例患者（58%）运动时心室率有显著反应，7例无反应，1例维持窦性心律。对于有反应者，RS4模式下心室起搏峰值率和双乘积显著高于VVI模式，分别为101.8±5.8次/分钟对74.3±0.4次/分钟以及20.1±2.9次/分钟×mmHg×10⁻³对15.5±3.7次/分钟×mmHg×10⁻³（p<0.001）。然而，平板运动时间（10.5±2.6分钟对9.7±3.3分钟）和做功量（5.51±2.01焦耳×10⁻⁵对4.97±2.33焦耳×10⁻⁵）无显著差异（p=0.22）。出院后，重复运动试验和24小时动态心电图监测分别在16例患者中的11例和18例患者中的15例证实了RS4功能。我们得出结论，由于心房感知不可靠，RS4-SRT起搏系统不能提供改善运动耐量所需的可靠频率应答。
