Meine M, Achtelik M, Hexamer M, Kloppe A, Werner J, Trappe H J
Department of Cardiology and Angiology, Marienhospital, Herne, Germany.
Pacing Clin Electrophysiol. 2000 Oct;23(10 Pt 1):1457-67. doi: 10.1046/j.1460-9592.2000.01457.x.
The evaluation of the heart rate response to exercise is important for the diagnosis of chronotropic incompetence and the assessment of a rate responsive algorithm of sensor-controlled pacemakers. The aim of the present study was to examine a classification of the chronotropic response at an individually moderate exercise level. Sixteen pacemaker patients (patient group, age 62.9 +/- 7.6 years) with sick sinus syndrome and 15 age-matched healthy subjects (control group, age 57.6 +/- 9.4 years) underwent a maximum cardiopulmonary exercise test on a treadmill after a protocol with individually selected incremental steps. To analyze the patients' intrinsic heart rate response, the rate responsive mode of the pacemaker was switched off. Chronotropic incompetence was diagnosed in eight patients whose maximal heart rate was < 80% of the age-predicted heart rate. The heart rate at the anaerobic threshold was significantly lower in the chronotropically incompetent subgroup than in the chronotropically competent patients and the healthy subjects (85.9 +/- 6.6 beats/min vs 100.3 +/- 9.9 beats/min and 112.9 +/- 11.7 beats/min, respectively). The chronotropic slope of the heart rate reserve as a function of the metabolic reserve was significantly higher in the control group than in the patient groups with either mild or severe chronotropic incompetence (0.94 +/- 0.17 vs 0.64 +/- 0.08 and 0.43 +/- 0.14, respectively). Furthermore, the chronotropically incompetent response could be divided into a linear type with and without a threshold, an exponential, and a logarithmic type. The anaerobic threshold was an objectively detectable breakpoint at an individually moderate exercise level that could be used for characterization of chronotropic function. At the anaerobic threshold, a physiological heart rate response was about 220--age--50 beats/min. A deviation of more than 10 beats/min below this physiological value characterized chronotropic incompetence.
评估运动时的心率反应对于变时性功能不全的诊断以及传感器控制起搏器的频率应答算法的评估具有重要意义。本研究的目的是在个体适度运动水平下检查变时性反应的分类。16例患有病态窦房结综合征的起搏器患者（患者组，年龄62.9±7.6岁）和15例年龄匹配的健康受试者（对照组，年龄57.6±9.4岁）按照个体选择的递增步骤方案在跑步机上进行了最大心肺运动试验。为了分析患者的固有心率反应，将起搏器的频率应答模式关闭。8例最大心率<年龄预测心率80%的患者被诊断为变时性功能不全。变时性功能不全亚组的无氧阈值时心率显著低于变时性功能正常的患者和健康受试者（分别为85.9±6.6次/分钟、100.3±9.9次/分钟和112.9±11.7次/分钟）。作为代谢储备函数的心率储备变时斜率在对照组中显著高于轻度或重度变时性功能不全的患者组（分别为0.94±0.17、0.64±0.08和0.43±0.14）。此外，变时性功能不全反应可分为有阈值和无阈值的线性类型、指数类型和对数类型。无氧阈值是个体适度运动水平下一个可客观检测到的转折点，可用于表征变时性功能。在无氧阈值时，生理性心率反应约为220-年龄-50次/分钟。低于该生理值超过10次/分钟的偏差表征变时性功能不全。
