De Vito F, Giordano A, Giannuzzi P, Tavazzi L
Division of Cardiology, 'Clinica del Lavoro Foundation', Veruno, Novara, Italy.
Eur Heart J. 1988 Apr;9 Suppl F:45-54. doi: 10.1093/eurheartj/9.suppl_f.45.
Two hundred and forty patients with recent inferior myocardial infarction were studied by a symptom-limited ergometric test with haemodynamic monitoring (triple lumen tip-thermistor Swan-Ganz catheter) in order to investigate and quantify the haemodynamic effects of exercise-induced myocardial ischaemia in post-infarct patients and to assess whether the ST-segment changes give any indication of the degree of ventricular impairment. One hundred and thirteen patients showed no ST-segment changes during excercise; ST-segment elevation in leads with abnormal Q wave occurred in 14 patients, ST-segment depression was recorded in 88 subjects, and both ST-segment elevation and depression were found in 27 patients. In subjects with no ST-segment shift, as well as in those with exercise-induced ST-segment elevation, the resting and exertional haemodynamic patterns were normal or nearly normal. In subjects showing ST-segment depression or both ST-segment elevation and depression during exercise the mean pulmonary wedge pressure was abnormally elevated (at peak exercise 25 +/- 8 and 24 +/- 7 mm Hg, respectively). However, 31% of these showed a normal haemodynamic pattern either at rest or during exercise. The number of leads with ST-segment depression and the sum of ST-segment depressions in standard ECG does not reliably indicate the degree of ischaemia-dependent left ventricular impairment. In contrast, in patients grouped on the basis of time of ST depression appearance, the lower the ischaemic threshold the more severe was the left ventricular impairment. Finally, to assess the relative role of both scar and ischaemia in producing left ventricular dysfunction, the haemodynamic patterns of patients with and without exercise-induced ST-segment depression were compared in subsets with similar echocardiographic wall asynergy extent (inferior, infero-apical, infero-septo-apical). Among patients with small or medium-sized scar, the exertional left ventricular filling pressure was normal in patients with no ST-segment depression and abnormally elevated in those with ST-segment depression. In patients with large infarct, the exercise pulmonary wedge pressure was similarly elevated in both the ischaemic and non-ischaemic group, but in the latter cardiac output increase during exercise was limited.
in patients with recent inferior myocardial infarction exercise-induced ST-segment depression is a marker of left ventricular impairment when the ischaemic threshold is low. The impairment consists of an abnormal elevation of left ventricular filling pressure in all subjects, associated with a reduced increase in cardiac output in patients with large infarct.
对240例近期发生下壁心肌梗死的患者进行了症状限制性运动负荷试验，并进行血流动力学监测（使用三腔顶端热敏电阻Swan-Ganz导管），以研究和量化运动诱发的心肌缺血对梗死患者血流动力学的影响，并评估ST段改变是否能提示心室功能损害的程度。113例患者运动期间未出现ST段改变；14例患者Q波异常导联出现ST段抬高，88例记录到ST段压低，27例患者同时出现ST段抬高和压低。在无ST段移位的患者以及运动诱发ST段抬高的患者中，静息和运动时的血流动力学模式正常或接近正常。在运动期间出现ST段压低或同时出现ST段抬高和压低的患者中，平均肺毛细血管楔压异常升高（运动高峰时分别为25±8和24±7 mmHg）。然而，其中31%的患者静息或运动时血流动力学模式正常。标准心电图中ST段压低的导联数和ST段压低总和并不能可靠地提示缺血依赖性左心室功能损害的程度。相反，在根据ST段压低出现时间分组的患者中，缺血阈值越低，左心室功能损害越严重。最后，为评估瘢痕和缺血在导致左心室功能障碍中的相对作用，在超声心动图显示室壁运动不协调程度相似（下壁、下-心尖部、下-间隔-心尖部）的亚组中，比较了有和无运动诱发ST段压低患者的血流动力学模式。在有小或中等大小瘢痕的患者中，无ST段压低的患者运动时左心室充盈压正常，而有ST段压低的患者则异常升高。在有大面积梗死的患者中，缺血组和非缺血组运动时肺毛细血管楔压均同样升高，但后者运动时心输出量增加受限。
在近期发生下壁心肌梗死的患者中，当缺血阈值较低时，运动诱发的ST段压低是左心室功能损害的标志。这种损害表现为所有患者左心室充盈压异常升高，在大面积梗死患者中伴有心输出量增加减少。
