Mizutani Y, Nakano S, Iwase T, Samoto T, Fujinami T
J Cardiogr. 1982 Mar;12(1):83-92.
To evaluate cardiac reserve in patients with angina pectoris, 10 healthy control subjects and 15 patients with angina pectoris were examined by exercise echocardiography. Exercise on the bicycle ergometer in supine position was imposed at 25 watts per min initially and the exercise was increased by 25 watts every 3 min until attainment of either maximal predicted heart rate or ST segment depression in the electrocardiogram (ECG) or appearance of severe chest pain. Blood pressure, two-dimensional echocardiogram at the level of the papillary muscle in the short-axis view (Fig. 1) and 12 leads ECG were recorded at the end of each exercise level. Cardiac response to the exercise was evaluated by blood pressure, areas of left ventricular cavity at the end diastole and end systole, percent change of the area, ejection fraction and mVCF, as shown in Figs. 2, 3 and 4. From these parameters, the behavior of cardiac response to exercise was divided into four types (cf. Fig. 5). Type A: left ventricular volume was increased slightly at the initial stage of exercise, and thereafter, the cardiac response was maintained by a gradual increase of myocardial contractility. Type B: initial response to exercise was similar to type A, but cardiac output was maintained only with an increase of heart rate in further exercise load. Type C: left ventricular contractility and increased left ventricular volume were observed from 25 watts load of exercise. Most of the control subjects responded as type A. Patients with angina who underwent 125 watts exercise showed type B response, while those who tolerated only 75 watts exercise revealed type C or type D (Table 1). The latter indicates decreased cardiac reserve to exercise. From the results of 10 patients who showed ST depression during exercise, deterioration of left ventricular contractile function appeared before ST segment depression, indicating that a change in mechanical pump function preceded electrical function of the myocardium (Fig. 6). It may be concluded that serial changes of cardiac parameters obtained from dynamic exercise echocardiography with an area-based method is useful to identify decreased cardiac reserve in patients with angina pectoris.
为评估心绞痛患者的心脏储备功能，对10名健康对照者和15名心绞痛患者进行了运动超声心动图检查。最初让受试者仰卧在自行车测力计上以每分钟25瓦的功率进行运动，每3分钟将运动强度增加25瓦，直至达到最大预测心率、心电图（ECG）出现ST段压低或出现严重胸痛。在每个运动水平结束时记录血压、乳头肌水平短轴视图的二维超声心动图（图1）和12导联心电图。通过血压、舒张末期和收缩末期左心室腔面积、面积变化百分比、射血分数和平均圆周缩短率来评估心脏对运动的反应，如图2、3和4所示。根据这些参数，将心脏对运动的反应行为分为四种类型（见图5）。A型：运动初期左心室容积略有增加，此后，心脏反应通过心肌收缩力的逐渐增加得以维持。B型：运动初期反应与A型相似，但在进一步增加运动负荷时，心输出量仅通过心率增加来维持。C型：从25瓦运动负荷开始观察到左心室收缩力增强和左心室容积增加。大多数对照者表现为A型反应。进行125瓦运动的心绞痛患者表现为B型反应，而仅能耐受75瓦运动的患者表现为C型或D型（表1）。后者表明运动心脏储备功能下降。从10名运动时出现ST段压低的患者结果来看，左心室收缩功能恶化出现在ST段压低之前，表明心肌机械泵功能的改变先于心肌电功能的改变（图6）。可以得出结论，采用基于面积法的动态运动超声心动图获得的心脏参数的系列变化，有助于识别心绞痛患者运动心脏储备功能下降。
