Wang C H, Cherng W J, Hung M J
Department of Internal Medicine, Chang Gung Memorial Hospital, Keelung, Taiwan.
Changgeng Yi Xue Za Zhi. 1997 Sep;20(3):163-73.
The diagnostic ability of dobutamine stress two-dimensional echocardiography is limited by the clarity of the echocardiographic image. In this study, left ventricular isovolumic relaxation time (IVRT) was modified and the effect of this modification on the diagnostic accuracy of dobutamine echocardiography (DE) in detecting ischemia was assessed.
DE was performed in 59 subjects (34 and 25 in the control and patient group, respectively). The results were compared with coronary angiography and stress scintigraphy. We focused on the changes of the IVRT, the corrected IVRT which was the IVRT corrected for heart rate, and the modified IVRT which is the corrected IVRT modified by a new-designed equation.
These isovolumic relaxation variables shortened with the increment of dobutamine dosage and were markedly prolonged when ischemia developed. The sensitivity and specificity of DE were 84% and 74%. However, using the prolongation of corrected IVRT and modified IVRT as indicators of ischemia, the specificity increased (from 74% to 91% and to 94%, respectively), without a significant reduction in sensitivity (from 84% to 76% and to 84%, respectively). Patients with positive results for these variables, as compared with negative results, had a significant result of more ischemic segments and a tendency of more diseased vessels.
The prolongation of these isovolumic relaxation variables during myocardial ischemia improves the diagnostic accuracy of DE and is also well correlated with the severity of ischemia.
多巴酚丁胺负荷二维超声心动图的诊断能力受超声心动图图像清晰度的限制。在本研究中，对左心室等容舒张时间（IVRT）进行了修正，并评估了这种修正对多巴酚丁胺超声心动图（DE）检测心肌缺血诊断准确性的影响。
对59名受试者（对照组34名，患者组25名）进行了DE检查。将结果与冠状动脉造影和负荷闪烁显像进行比较。我们重点关注IVRT、校正心率后的IVRT（校正IVRT）以及通过新设计方程修正的校正IVRT（修正IVRT）的变化。
这些等容舒张变量随着多巴酚丁胺剂量的增加而缩短，在心肌缺血发生时显著延长。DE的敏感性和特异性分别为84%和74%。然而，以校正IVRT和修正IVRT的延长作为心肌缺血的指标，特异性增加（分别从74%提高到91%和94%），而敏感性无显著降低（分别从84%降至76%和84%）。这些变量结果为阳性的患者与结果为阴性的患者相比，缺血节段更多，病变血管更多的趋势更明显。
心肌缺血期间这些等容舒张变量的延长提高了DE的诊断准确性，并且与缺血严重程度也有良好的相关性。
