Meyers D G, Bendon K A, Hankins J H, Stratbucker R A
Department of Internal Medicine, University of Nebraska College of Medicine, Omaha 68105.
Am Heart J. 1990 Feb;119(2 Pt 1):272-6. doi: 10.1016/s0002-8703(05)80016-x.
Although exercise-induced ST segment depression is thought to be unreliable marker of myocardial ischemia in the presence of resting electrocardiographic changes, this conclusion is based on limited and disparate data from studies often lacking acceptable measures of ischemia. To determine the diagnostic accuracy of the ST segment response in a blinded prospective protocol, we compared ST deviation to thallium201 SPECT scintigraphy in 95 patients during exercise. Diagnostic accuracy was poor in the 95 patients with resting abnormalities: left bundle branch block (LBBB) = 70%, complete right bundle branch block (cRBBB) = 75%, incomplete right bundle branch block (incRBBB) = 79%, intraventricular conduction delay (IVCD) = 44%, left ventricular hypertrophy (LVH) = 59%, digitalis = 53%, compared with a diagnostic accuracy of 90% in 29 patients without resting changes. There were 20 false negative and 17 false positive ST segment responses. The extent and direction of resting ST deviation varied substantially and had no influence on diagnostic accuracy. The extent of change in ST deviation with exercise required for a positive response did not alter diagnostic accuracy: -1.0 mm = 61%, -1.5 mm = 63%, and -2.0 = 61%. While the location of regional ischemia did not influence the accuracy of ST segment analysis, a QRS duration less than 120 msec did improve diagnostic accuracy. Our data confirm that ST segment analysis with exercise testing is not reliable in patients with resting electrocardiographic abnormalities and demonstrates that accuracy is not improved by adjusting for either resting or exercise-induced ST segment changes or for location of the ischemic region.
尽管在静息心电图改变的情况下，运动诱发的ST段压低被认为是心肌缺血的不可靠标志物，但这一结论是基于有限且不一致的数据，这些研究往往缺乏可接受的缺血测量方法。为了在一项盲法前瞻性研究方案中确定ST段反应的诊断准确性，我们在95例患者运动期间将ST段偏移与铊201单光子发射计算机断层扫描（SPECT）闪烁显像进行了比较。在95例有静息异常的患者中诊断准确性较差：左束支传导阻滞（LBBB）为70%，完全性右束支传导阻滞（cRBBB）为75%，不完全性右束支传导阻滞（incRBBB）为79%，室内传导延迟（IVCD）为44%，左心室肥厚（LVH）为59%，洋地黄影响为53%，而在29例无静息改变的患者中诊断准确性为90%。有20例假阴性和17例假阳性ST段反应。静息ST段偏移的程度和方向差异很大，且对诊断准确性没有影响。阳性反应所需的运动时ST段偏移变化程度并未改变诊断准确性：-1.0毫米时为61%，-1.5毫米时为63%，-2.0毫米时为61%。虽然局部缺血的部位不影响ST段分析的准确性，但QRS时限小于120毫秒确实提高了诊断准确性。我们的数据证实，对于有静息心电图异常的患者，运动试验时的ST段分析不可靠，并表明通过调整静息或运动诱发的ST段改变或缺血区域的位置并不能提高准确性。
