Wiens R D, Lafia P, Marder C M, Evans R G, Kennedy H L
Am J Cardiol. 1984 Jul 1;54(1):74-8. doi: 10.1016/0002-9149(84)90306-0.
Chronotropic incompetence has been found to be an important predictor of obstructive coronary artery disease (CAD). However, few data define the normal heart rate response to progressive exercise and allow a clear definition of chronotropic incompetence. In this study, 312 patients who underwent an exercise stress test and coronary angiography were evaluated. The exercise heart rates of 140 normal subjects were used to define the normal mean heart rate at progressive work loads. Two standard deviations of the mean were chosen to represent a normal response at various levels of exercise. Analysis of the exercise heart rates in 172 patients who had CAD revealed 16 patients who had a peak exercise heart rate below 2 standard deviations of the mean. Of the 16 patients, 5 had 1-vessel, 5 had 2-vessel and 6 had 3-vessel CAD. Of 65 patients who had no significant ST-segment shift and who did not reach 85% of age-predicted heart rate, 13 (20%) had an inappropriately low heart rate for the work load performed. Each of the 13 patients had CAD. Of the 172 patients with CAD, those with chronotropic incompetence exercised further than the patients who did not have chronotropic incompetence (9.4 +/- 2.1 vs 7.0 +/- 3.4 METs, p less than 0.01). In conclusion, chronotropic incompetence is a relatively infrequent occurrence in an exercise test population; however, this finding, when present, is relatively specific for CAD, and may be useful in detecting patients with CAD who have an indeterminate exercise test.
变时性功能不全已被发现是阻塞性冠状动脉疾病（CAD）的一个重要预测指标。然而，很少有数据能明确正常心率对渐进性运动的反应，也无法清晰界定变时性功能不全。在本研究中，对312例行运动负荷试验和冠状动脉造影的患者进行了评估。用140名正常受试者的运动心率来确定渐进性工作负荷下的正常平均心率。选择平均心率的两个标准差来代表不同运动水平下的正常反应。对172例CAD患者的运动心率分析显示，有16例患者的运动峰值心率低于平均心率的2个标准差。在这16例患者中，5例为单支血管病变，5例为双支血管病变，6例为三支血管病变。在65例无显著ST段移位且未达到年龄预测心率85%的患者中，13例（20%）的心率对于所进行的工作负荷而言过低。这13例患者均患有CAD。在172例CAD患者中，变时性功能不全的患者比无变时性功能不全的患者运动得更多（9.4±2.1代谢当量对7.0±3.4代谢当量，p<0.01）。总之，在运动试验人群中，变时性功能不全相对少见；然而，这一发现一旦出现，对CAD具有较高的特异性，可能有助于检测运动试验结果不确定的CAD患者。
