重复运动试验的心肌缺血预适应作用的研究

The research on myocardial ischemic precondition effect of repeated treadmill exercise tests

目的观察运动试验诱发的心肌缺血能否减轻随后运动试验引起的心肌缺血的严重程度及降低心律失常的发生率。方法稳定型劳力性心绞痛患者40例,依序进行两次平板运动试验。两次运动量相同,两次运动间隔12 m in。对比两次ST段压低1 mm出现时间(1 mm STD时间);ST段压低大于1mm持续时间(总缺血时间);ST段压低最大程度(最大STD);ST段恢复1 mm的时间(1 mm恢复时间);表现缺血的导联数(1 mm STD导联数);心律失常及心绞痛发生情况。结果与第1次运动试验相比,第2次运动试验的1 mm STD时间从490 s延长到620 s(P<0.001);总缺血时间从510 s减少到350 s(P<0.001);最大STD从3.1 mm降至1.2 mm,两次比较差异有显著性(P<0.001);1 mm恢复时间从420 s缩短到180 s(P<0.001);1 mm STD导联数从4.2个减少到2.3个(P<0.01)。40例患者中35例首次运动中发作心绞痛,其中30例再次运动中症状明显减轻,5例未发作心绞痛。第1次运动试验后心律失常的发生率62.5%(25例),而第2次运动试验后心律失常的发生率为20%(8例)。结论重复运动试验作为临床心肌缺血预适应的方法可提高稳定型劳力性心绞痛患者的缺血阈值,增强心肌对缺氧的耐受,减轻心肌损伤程度,降低心律失常的发生率。

Objective To examine whether myocardial ischemia induced by repeated exercise tests can reduce the severity of ischemia and the incidence of arrhythmias induced by subsequent exercise test. Methods Fourty patients with stable effort angina pectoris underwent two treadmill exercise tests at 12-minute intervals. The two exercise tests were of similar work and load, and the data between the two tests were compared. Results Compared with the first test, time to the point when ST segment depressed no less than 1 mm from the beginning of the test （ 1 mm ST depression）in second test was prolonged from 490 to 620 seconds （P 〈 0. 001 ）, as well as duration of ST segment depressed no less than 1 mm（the total ischemic time）was markedly shortened from 510 to 350 seconds （P 〈 0. 001 ） ;ST segment depressed to the most declined from 3. 1 mm to 1.2 mm（ P 〈 0. 001 ） ; time to the point when ST segment returned to l mm（the recovery time）reduced from 420 seconds to 180 seconds （ P 〈 0. 001 ）, and the total leads of ischemia （ leads of 1 mm STD） depressed from 4. 2 to 2. 3 （ P 〈 0. 01 ）. Thirty five patients had angina pectoris during the first test, and the syndrome in 30 of them lessened. Five of them didnt have angina pectoris in the second test. Arrhythmias occur red in 25 cases in the first test while 8 cases in the second test（ P 〈 0. 01 ）. Conclusion It was found that repeated exercise test as a way of myocardial precondition could make myocardium a higher ischemic threshold and reduce the severity of ischemia and the incidence of arrhythimias.