Wilson R F, Marcus M L, Christensen B V, Talman C, White C W
Department of Medicine, University of Minnesota, Minneapolis.
Circulation. 1991 Feb;83(2):412-21. doi: 10.1161/01.cir.83.2.412.
The accuracy of exercise electrocardiography in detecting a physiologically significant coronary artery stenosis has been assessed previously by comparing the exercise test with a coronary arteriogram. The inherent inaccuracy of visually determined percent diameter stenosis measurements might have lead to the conclusion that the exercise electrocardiogram was less accurate than it truly was. To determine the accuracy of the exercise electrocardiography in detecting a physiologically significant coronary stenosis, we studied 40 patients with one-vessel, one-lesion coronary artery disease, a normal resting electrocardiogram, and no hypertrophy or prior infarction. Each patient underwent exercise electrocardiography (Bruce protocol) that was interpreted as abnormal if the ST segment developed 0.1-mV or greater depression 80 msec after the J point. The physiological significance of each coronary stenosis was assessed by measuring of coronary flow reserve (peak divided by resting blood flow velocity) in the stenotic artery using a Doppler catheter and intracoronary papaverine (normal, 3.5 or greater peak/resting velocity). The percent diameter and percent area stenosis produced by each lesion were determined using quantitative angiography (Brown/Dodge method). Of the 17 patients with reduced coronary flow reserve (3.5 or greater peak/resting blood flow velocity) in the stenotic artery, 14 had an abnormal exercise electrocardiogram (sensitivity, 0.82; 95% confidence interval, 0.70-0.94). Conversely, 20 of 23 patients with normal coronary flow reserves had normal exercise tests (specificity, 0.87; 95% confidence interval, 0.77-0.97). The exercise electrocardiogram was abnormal in each of 11 patients with markedly reduced coronary flow reserve (less than 2.5 peak/resting velocity) and in three of six patients with moderately reduced reserve (2.5-3.4 peak/resting velocity). The products of systolic blood pressure and heart rate at peak exercise were significantly correlated with coronary reserve in patients with truly abnormal exercise tests. In comparison, the sensitivity (0.61; 95% confidence interval, 0.46-0.76) and specificity (0.73; 95% confidence interval, 0.60-0.86) of exercise electrocardiography in detecting a 60% or greater diameter stenosis may be significantly lower (p less than 0.05). Exercise electrocardiography, therefore, was a good predictor of the physiological significance (assessed by coronary flow reserve) of a coronary stenosis in patients with a normal resting electrocardiogram and no hypertrophy or prior infarction. Its value in a broader and larger patient population will require further study. These results, however, underscore the importance of a physiological gold standard in assessing the accuracy of noninvasive studies for detecting coronary artery disease.
先前已通过将运动试验与冠状动脉造影进行比较，评估了运动心电图检测具有生理学意义的冠状动脉狭窄的准确性。视觉判定的直径狭窄百分比测量存在固有不准确性，这可能导致得出运动心电图比其实际准确性更低的结论。为了确定运动心电图检测具有生理学意义的冠状动脉狭窄的准确性，我们研究了40例患有单支血管、单处病变的冠状动脉疾病、静息心电图正常且无肥厚或既往梗死的患者。每位患者均接受运动心电图检查（Bruce方案），如果ST段在J点后80毫秒出现0.1毫伏或更大的压低，则判定为异常。使用多普勒导管和冠状动脉内注射罂粟碱，通过测量狭窄动脉的冠状动脉血流储备（峰值除以静息血流速度）来评估每个冠状动脉狭窄的生理学意义（正常情况下，峰值/静息速度为3.5或更高）。使用定量血管造影术（Brown/Dodge方法）确定每个病变导致的直径狭窄百分比和面积狭窄百分比。在17例狭窄动脉中冠状动脉血流储备降低（峰值/静息血流速度为3.5或更高）的患者中，14例运动心电图异常（敏感性为0.82；95%置信区间为0.70 - 0.94）。相反，在23例冠状动脉血流储备正常的患者中，20例运动试验正常（特异性为0.87；95%置信区间为0.77 - 0.97）。在11例冠状动脉血流储备显著降低（峰值/静息速度小于2.5）的患者中，每例患者的运动心电图均异常，在6例储备中度降低（峰值/静息速度为2.5 - 3.4）的患者中，有3例异常。在运动试验真正异常的患者中，运动高峰时的收缩压与心率乘积与冠状动脉储备显著相关。相比之下，运动心电图检测直径狭窄60%或更大时的敏感性（0.61；95%置信区间为0.46 - 0.76）和特异性（0.73；95%置信区间为0.60 - 0.86）可能显著更低（p小于0.05）。因此，对于静息心电图正常且无肥厚或既往梗死的患者，运动心电图是冠状动脉狭窄生理学意义（通过冠状动脉血流储备评估）的良好预测指标。其在更广泛和更大患者群体中的价值需要进一步研究。然而，这些结果强调了生理学金标准在评估检测冠状动脉疾病的非侵入性研究准确性方面的重要性。
