平板运动试验的心率校正ST段下移指标对冠心病的预测价值

目的：探讨平板运动试验中ST段下移、△ST／△HR指数和最大ST／HR斜率预测冠心病的价值。方法：对已行冠脉造影检查并在造影前有平板运动试验资料的120例患者资料进行分析。研究ST段下移、△ST／△HR指数和最大ST／HR斜率诊断冠心病的敏感性、特异性。结果：120例患者冠脉造影阳性者66例。ST段下移、△ST／△HR指数和最大ST／HR斜率的（敏感性和特异性）分别为（69．7％、72．2％）、（92．4％、88．9％）和（93．9％、90．7％）。冠心病组△ST／△HR指数和最大ST／HR斜率敏感性、特异性均显著高于非冠心病组（P〈0．01）。结论：平板运动试验中采用心率校正的ST段指标能提高对冠心病的诊断价值。     

心率调整的ST段降低方法定性和定量检测冠心病的研究

目的探讨心率调整的ST段降低方法定性和定量检测冠心病的价值,并把ST/HR斜率和ST/HR指数两种指标和传统ST段指标进行了系统比较。方法选取2001年1月至2002年3月行平板运动ECG试验并在随后3周内住院行冠状动脉造影的可疑冠心病患者共173例,应用Cornell运动试验方案,分别测定并计算运动试验过程中ST段变化值及ST/HR斜率和ST/HR指数值,以冠状动脉造影结果作为诊断冠心病的标准。结果传统ST段指标、ST/HR斜率和ST/HR指数诊断冠心病的敏感性分别为68%、86%和81%,特异性分别为70%、85%和81%。ST/HR斜率和ST/HR指数诊断冠心病的敏感性、特异性均明显高于传统ST段指标(P<0.05)。传统ST段指标(ST段降低≥0.2mV)、ST/HR斜率和ST/HR指数定量识别冠心病3支血管病变的敏感性分别为30%、81%和64%,特异性分别为70%、65%和69%。ST/HR斜率和ST/HR指数识别冠心病3支血管病变的敏感性显著高于传统ST段指标(P<0.001),特异性无显著性差异(P>0.05)。结论心率调整的ST段降低指标、ST/HR斜率和ST/HR指数与传统ST段指标相比能明显提高运动ECG试验定性诊断冠心病的敏感性和特异性。与传统ST段指标相比,ST/HR斜率和ST/HR指数明显提高了运动ECG试验定量识别冠心病3支血管病变的敏感性。     

活动平板试验中收缩压恢复比对冠心病的预测价值

目的：研究活动平板试验中收缩压恢复比（rSBP）对冠心病的诊断价值。方法：99例患者接受活动平板试验和冠状动脉造影,分为冠心病组（56例,冠脉造影阳性）、高血压病组（18例,冠脉造影阴性）和对照组（25例,冠脉造影阴性）,对比分析rSBP和ST／HR斜率对冠心病的诊断价值。结果：冠心病组、高血压病组3minrSBP值[（0．94±0．09）、（0．80±0．10）]显著高于对照组的（0．74±0．06）,分别P〈0．01,〈0．05。rSBP诊断冠心病的敏感性、特异性、准确性分别为89．3％、76．7％、特异性、准确性分别为90．7％、90．3％、94．2％。结论：斜率可提高诊断的特异性和准确性。83．3％,联合rSBP和ST／HR斜率诊断冠心病的敏感性、rSBP可作为诊断冠心病的无创指标之一,联合ST／HR     

食管心房调搏负荷试验心率校正ST段变化对冠心病的诊断价值

目的：探讨经食管心房调搏负荷试验（TEAPT）心率校正ST段变化对冠心病的诊断价值。方法：观察55例正常对照组和38例冠心病组患者的试验结果，测定每一时点心电图ST段压低值，计算最大ST／HR斜率和ΔST／HR指数，并比较其与传统ST段压低标准的诊断效能。结果：正常组最大ST／HR斜率、ΔST／HR指数和ST段标准的95％上限值分别为1．1μV／次／min、0．77μV/次／min和70μV，以此为界限值，最大ST／HR斜率诊断冠心病的敏感性，准确性显著大于传统ST段压低标准（P＜0．05）。结论：食管心房调搏负荷试验无创、安全、经济，最大ST／HR斜率诊断冠心病具有较高的准确性。     

平板运动试验心脏变时功能不全对冠心病的诊断价值

目的探讨平板运动试验心脏变时功能不全对冠心病的诊断价值。方法将240例临床拟诊冠心病患者先后行平板运动试验及冠状动脉造影检查，并按冠状动脉造影结果分为冠心病组和非冠心病组，分析比较两组间心脏变时性指标。运动后最大心率〈预测最大心率的85％和变时性指数（CRI）〈0．8为心脏变时功能不全。结果冠心病组运动后最大心率、变时性指数两种变时功能不全的指标均低于非冠心病组（P〈0．01），与传统的ST段标准相比，变时功能不全诊断冠心病的敏感性、特异性、准确性无明显差异（P〉0．05），ST段标准伴变时功能不全诊断冠心病的特异性、准确性均较ST段标准明显增高，差异具有统计学意义（P〈0．05）。结论平板运动试验心脏变时功能不全是诊断冠心病的有用指标，与传统的ST段标准联合应用可提高对冠心病的诊断价值。     

平板运动试验心率恢复环在冠心病诊断中的应用价值

目的 探讨平板运动试验心率恢复环(HRRL)的变化及意义。方法 分析165例确诊或凝似冠心病(CHD)行冠脉造影的亚极量乎板运动试验前后心率恢复环的动态变化，计算HRRL诊断CHD的敏感性及特异性，并与常用的ST段标准进行比较。结果 平板运动试验ST段标准、HRRL标准诊断CHD的敏感性分别为63．2％和81．1％；特异性分别82％和80％。结论 与常用的ST段标准进行比较，心率恢复环在冠心病诊断中敏感性高，特异性无显差别。’     

平板运动试验不同标准诊断冠心病的价值

目的探讨活动平板运动心电图ST段压低、QRS积分和ST／HR指数3种标准诊断冠心病的价值。方法选取可疑冠心病患者共177例,以冠状动脉造影结果为金标准,评价平板运动心电图3种标准诊断冠心病的敏感性和特异性。结果ST段压低、QRS积分和ST／HR指数诊断冠心病的敏感性和特异性均依次增高,ST／HR指数与ST段压低相比敏感性和特异性差异均有显著性意义（P〈0．05）,而QRS积分与ST段压低相比仅特异性差异有显著性意义（P〈005）。另外,ST／HR指数随着冠状动脉病变数目的增多而增高,QRS积分随着病变数目的增多而减少。结论①ST／HR指数可提高对冠心病的诊断价值;②当存在干扰性ST段压低时,采用QRS积分是较好的选择;③ST／HR指数、QRS积分可预计冠状动脉病变情况。     

平板运动试验心率校正的ST段压低参数对冠心病诊断价值的探讨

探讨心率校正的ST段压低参数诊断冠状动脉 (简称冠脉 )病变的准确性 ,12 8例患者接受次极量平板运动试验和冠脉造影。观察各例患者运动中心率相关的ST段压低最大速度即最大ST段 /心率斜率 ,最大心率时ST段与静息时ST段压低值之差除以最大心率与静息心率之差即ΔST/HR指数 ,以及ST段压低 ,观察值与阳性判断标准比较。结果显示 ,最大ST/HR斜率诊断冠心病的敏感性、特异性及诊断符合率最高 ,分别为 94.1%、92 .3%、94.5 % ,ST段压低诊断冠心病的敏感性、特异性及诊断符合率最低 ,分别为 74.5 %、6 9.2 %、73.4%。最大ST/HR斜率在冠脉不同程度病变间无重叠 ,其它参数虽与冠脉病变程度有平行关系 ,但有较大程度的重叠。结论 :心率校正的ST段压低参数显著提高了对冠心病的诊断价值 ,其中最大ST/HR斜率对冠脉病变支数有定量诊断价值     

性别对心率调整心电图ST段降低方法诊断冠心病的影响

目的　就性别对心率 (HR)调整心电图ST段降低方法诊断冠心病的影响进行探讨。方法　选取可疑冠心病患者共 173例 ,测定运动试验过程中心电图ST段变化值及ST/HR斜率和ST/HR指数 ,以冠状动脉 (冠脉 )造影结果作为诊断冠心病的标准。结果　ST/HR斜率和ST/HR指数诊断冠心病的敏感性、特异性均明显高于传统ST段指标 (P <0 0 5 )。ST/HR斜率和ST/HR指数诊断冠心病的敏感性男性患者分别提高 2 3%和 16 % ,女性患者分别提高 5 0 %和 4 2 % ,差异均有显著性意义 (P <0 0 5 ) ;而ST/HR斜率和ST/HR指数诊断冠心病的特异性 ,男性患者无明显提高 (P >0 0 5 ) ,女性患者分别提高 5 8%和 5 0 % (P <0 0 5 )。结论　ST/HR斜率和ST/HR指数与传统ST段指标相比 ,女性患者诊断冠心病的敏感性和特异性明显提高 ,男性患者敏感性有提高 ,特异性无明显变化     

运动心电图试验心率校正的S-T段改变在老年人冠心病临床诊断中的应用

目的　评价运动心电图试验心率校正的ST段改变在老年人冠心病临床诊断中的意义。方法　 61例老年冠心病患者 (冠心病组 )和 47名健康老年人 (对照组 )按Bruce改良方案进行运动平板试验 ,测定受试者心率校正的ST段值 (最大ST/HR斜率 )和ST段压低值。结果　最大ST/HR斜率对冠心病诊断的敏感性 (94% )和特异性 (96% )均优于普通运动心电图试验 (分别为65 % ,76% ) ,两组比较差异有显著性 (P <0 .0 5 ) ;冠心病组的最大ST/HR斜率为 (2 .8± 1.5 ) μV/bpm ,对照组的ST/HR斜率为 (0 .7± 1.1) μV/bpm ,两组比较差异有非常显著性 (P <0 .0 1) ;参照冠脉造影的结果 ,其提示 1～ 2支血管病变的敏感性为 80 %、特异性为 85 % ;提示 3支血管病变的敏感性为 88%、特异性为 78%。结论　心率校正的ST段改变对诊断冠心病有重要价值 ,其敏感性、特异性均明显高于普通运动试验 ,可作为评价心肌缺血的参考     

ST/HR hysteresis: Exercise and recovery phase ST depression/heart rate analysis of the exercise ECG

ST segment depression/heart rate (ST/HR) hysteresis is a recently introduced novel computer method for integrating the exercise and recovery phase ST/HR analysis for improved detection of coronary artery disease (CAD). It is a continuous diagnostic variable that extracts the prevailing direction and average magnitude of the hysteresis in ST depression against HR during the first 3 consecutive minutes of postexercise recovery. This article reviews the development and evaluation of this new method in a clinical population of 347 patients referred for a routine bicycle exercise electrocardiographic (ECG) test at Tampere University Hospital, Finland. Of these patients, 127 had angiographically proven CAD, whereas 13 had no CAD according to angiography, 18 had no perfusion defect according to Tc-99m-sestamibi myocardial imaging and single photon emission computed tomography, and 189 were clinically normal with respect to cardiac diseases. For each patient, the values for ST/HR hysteresis, ST/HR index, end-exercise ST depression, and recovery ST depression were determined for each lead of the Mason-Likar modification of the standard 12-lead exercise ECG and maximum value from the lead system (aVL, aVR, and V₁ excluded). The area under the receiver operating characteristics curve (ie, the discriminative capacity) of the ST/HR hysteresis was 89%, which was significantly larger than that of the end-exercise ST depression (76%, P < .0001), recovery ST depression (84%, P = .0063) or ST/HR index (83%, P = .0023), indicating the best diagnostic performance of the ST/HR hysteresis in detection of CAD regardless of the partition value selection. Furthermore, the superior diagnostic performance of the method was relatively insensitive to the ST segment measurement point or to the ECG lead selection. These results suggest that the ST/HR hysteresis improves the clinical utility of the exercise ECG test in detection of CAD.     

Predictive value and limitations of the ST/HR slope

To assess the value and predictive limitations of the exercise ST/HR slope, exercise test results were compared in 50 patients with stable angina and in 17 normal subjects with those in two groups known to have a high prevalence of inaccurate electrocardiographic responses to exercise. The last two groups included 51 patients tested within three weeks of acute myocardial infarction and 17 with important aortic regurgitation but no coronary disease. Of the normal subjects, 16 (94%) had ST/HR values less than or equal to 1 X 1 microV/beat/min. Of those with stable angina pectoris, 42 of 46 (91%) patients with coronary artery disease had ST/HR slopes ranging from 1 X 2 to 20 X 0 microV/beat/min, with false negative findings (slopes less than or equal to 1 X 1 microV/beat/min) in only four (9%). In contrast, of those with recent myocardial infarction, 15 of 42 (36%) with coronary disease had false negative slopes, including 12 of 20 (60%) with anterior wall injury. Of those with aortic regurgitation, conversely, 14 of 16 (88%) patients with calculable ST/HR slopes had values greater than 1 X 1 microV/beat/min despite the absence of coronary disease. Despite the accuracy of the test in patients with stable angina, false negative results are common in those after recent myocardial infarction, and false positive results occur often in those with abnormal volume loading due to aortic regurgitation.     

Predictive value and limitations of the ST/HR slope.

To assess the value and predictive limitations of the exercise ST/HR slope, exercise test results were compared in 50 patients with stable angina and in 17 normal subjects with those in two groups known to have a high prevalence of inaccurate electrocardiographic responses to exercise. The last two groups included 51 patients tested within three weeks of acute myocardial infarction and 17 with important aortic regurgitation but no coronary disease. Of the normal subjects, 16 (94%) had ST/HR values less than or equal to 1 X 1 microV/beat/min. Of those with stable angina pectoris, 42 of 46 (91%) patients with coronary artery disease had ST/HR slopes ranging from 1 X 2 to 20 X 0 microV/beat/min, with false negative findings (slopes less than or equal to 1 X 1 microV/beat/min) in only four (9%). In contrast, of those with recent myocardial infarction, 15 of 42 (36%) with coronary disease had false negative slopes, including 12 of 20 (60%) with anterior wall injury. Of those with aortic regurgitation, conversely, 14 of 16 (88%) patients with calculable ST/HR slopes had values greater than 1 X 1 microV/beat/min despite the absence of coronary disease. Despite the accuracy of the test in patients with stable angina, false negative results are common in those after recent myocardial infarction, and false positive results occur often in those with abnormal volume loading due to aortic regurgitation.     

ST/HR slope during prostacyclin treatment: an improved method to identify patients with advanced coronary artery disease

Constriction of atherosclerotic coronary segments during exercise may further reduce coronary flow reserve in patients with coronary artery disease. This could influence the linear regression analysis of the heart rate-related changes in ST-segment depression (ST/HR slope) thereby limiting the accuracy of this method in identifying the severity of the disease. To test this hypothesis, the exercise related ST/HR slopes on placebo were compared with those obtained during coronary vasodilation induced by a prostacyclin analogue (iloprost 6 ng kg-1 min-1) in 42 anginal patients with documented coronary artery disease. In seven of these, the same protocol was repeated during right heart catheterization. The overall diagnostic accuracy of the ST/HR slope on iloprost was better than on placebo in patients with advanced coronary artery disease. This was due mainly to a consistent rightward shift of the ST/HR slope in patients with one- and two-vessel, but not three-vessel disease or left main stem disease. The reason for the greater effects of iloprost on ST/HR slopes in patients with a lesser degree of atherosclerosis remains unclear. However, coronary blood flow was higher during drug infusion, which suggests that iloprost may prevent the occurrence of dynamic coronary events able to reduce the maximum coronary flow reserve during exertion. This mechanism may be predominant in patients with minor coronary artery disease.     

Identification of anatomically extensive coronary artery disease by the exercise ECG ST segment/heart rate slope

To assess the ability of the ST segment/heart rate (ST/HR) slope to identify three-vessel coronary disease and the relationship between the ST/HR slope and the anatomic extent of disease as determined by the Gensini and Duke jeopardy scores, the exercise ECGs of 128 patients with stable angina were compared with findings at coronary cineangiography. A ST/HR slope greater than or equal to 6 microV/beat/min identified three-vessel coronary disease with a sensitivity of 93% compared with sensitivities of only 50% for early positive standard test responses (p less than 0.001) and 66% for markedly positive standard test responses (p less than 0.01). The negative predictive value of this ST/HR slope partition for three-vessel disease was 94%. Patients with ST/HR slopes greater than or equal to 6 who did not have three-vessel disease had anatomically more extensive obstruction than did patients with lower test values (mean Gensini score 43 +/- 5 vs 22 +/- 3, p less than 0.002 and mean jeopardy score 4.8 +/- 0.4 vs 3.0 +/- 0.3, p less than 0.01). Test performance of the calculated ST/HR slope exceeded that of a simplified index derived by dividing the total change in ST segment depression by the total change in heart rate. These findings demonstrate that a ST/HR slope greater than or equal to 6 is highly sensitive for the identification of three-vessel coronary disease and also identifies patients with anatomically severe obstruction. A ST/HR slope less than 6 makes three-vessel coronary disease or otherwise anatomically extensive coronary obstruction unlikely.     

Heart rate adjustment of exercise-induced ST segment depression. Improved risk stratification in the Framingham Offspring Study

BACKGROUND. Simple heart rate adjustment of ST segment depression during exercise (delta ST/HR index) and the pattern of ST depression as a function of heart rate during exercise and recovery (the rate-recovery loop) have been shown to improve the ability of the exercise electrocardiogram to detect the presence of coronary heart disease (CHD), but the performance of these methods for the prediction of future coronary events remains to be examined. METHODS AND RESULTS. We compared the delta ST/HR index and the rate-recovery loop with standard electrocardiographic criteria for prediction of CHD events in 3,168 asymptomatic men and women in the Framingham Offspring Study who underwent treadmill exercise electrocardiography and who, at entry, were free of clinical and electrocardiographic evidence of CHD. After a mean follow-up of 4.3 years, there were 65 new CHD events: four sudden deaths, 24 new myocardial infarctions, and 37 incident cases of angina pectoris. When a Cox proportional hazards model with adjustment for age and sex was used, a positive exercise electrocardiogram by standard criteria (greater than or equal to 0.1 mV horizontal or downsloping ST segment depression) was not predictive of new CHD events (chi 2 = 0.40, p = 0.52). In contrast, stratification according to the presence or absence of a positive delta ST/HR index (greater than or equal to 1.6 microV/beat/min) and a positive (counterclockwise) rate-recovery loop was associated with CHD event risk (chi 2 = 9.45, p less than 0.01) and separated subjects into three groups with varying risks of coronary events: high risk, when both tests were positive (relative risk 3.6; 95% confidence interval, 2.4-5.4); intermediate risk, when either the delta ST/HR index or the rate-recovery loop was positive (relative risk, 1.9; 95% confidence interval, 1.3-2.8); and low risk, when both tests were negative. After multivariate adjustment for age, sex, smoking, total cholesterol level, fasting glucose level, diastolic blood pressure, and electrocardiographic evidence of left ventricular hypertrophy, the combined delta ST/HR index and rate-recovery loop criteria remained predictive of coronary events (chi 2 = 5.45, p = 0.02). CONCLUSIONS. Heart rate adjustment of ST segment depression by the delta ST/HR index and the rate-recovery loop during exercise electrocardiography can improve prediction of future coronary events in asymptomatic men and women.     

Evaluation of coronary artery disease by an improved method of exercise electrocardiography: the ST segment/heart rate slope

Analysis of the rate-related change in exercise-induced ST segment depression, the ST/HR slope, has been shown to significantly improve the accuracy of the exercise ECG for the identification of patients with coronary artery disease and for the recognition of patients with stable angina pectoris who have anatomically or functionally severe coronary artery obstruction. This method, in effect, normalizes the extent of ST segment depression for heart rate, which serves as an index of exercise-induced augmentation of myocardial oxygen demand. While preserving the specificity of the exercise ECG at greater than 90%, an ST/HR slope value of 1.1 microV/bpm as an upper limit of normal improved exercise test sensitivity from 57% to 91% in patients with stable angina who were examined using standard Bruce protocols and three monitoring leads. In addition, an ST/HR slope value of 6.0 microV/bpm was found to partition patients with and without three-vessel coronary artery disease with a sensitivity of 78%, specificity of 97%, positive predictive value of 93%, and overall test accuracy of 90%. No other criteria based on standard ECG interpretation performed as well as the ST/HR slope for the recognition of three-vessel disease in these patients. Further, patients with high ST/HR slopes who did not have three-vessel coronary disease could be shown to have functionally severe two-vessel disease by radionuclide cineangiography. These data suggest that the ST/HR slope can improve the evaluation and management of patients with possible coronary disease. Additional improvement in ST/HR slope accuracy and applicability is likely to result from modification of exercise protocols to reduce heart rate increments between stages, an increase in monitoring leads to include CM5, and computer analysis of the ST segment depression.     

ST/HR slope and improved exercise ECG detection of myocardial ischemia in patients with suspected coronary artery disease.

Predictive values of ST/HR slope and ST-segment displacement during symptom-limited exercise were determined in 85 patients who underwent coronary angiography for suspected coronary artery disease, using perfusional and functional radionuclide images with 99mTc-2-methoxy-isobutil-isonitrile as an index of stress-induced myocardial ischemia. ST/HR slope showed a better sensitivity than conventional stress-induced changes of ST-segment displacement (96% vs. 73%, respectively). In patients with clinical suspicion of coronary artery disease, the main result was the negative predictive value of ST/HR slope when compared with conventional ST-segment displacement (98% vs. 41%). ST/HR slope was unable to perfectly separate patients with different degrees of ischemia, however, subjects without scintigraphic signs of stress-induced ischemia and patients with ischemic impairment in three myocardial regions were correctly identified as distinct populations. In patients with a previous myocardial infarction, no difference was found between the two criteria and a wide overlap of ST/HR slope values was present. The authors conclude that ST/HR slope is useful to detect the rate of change in electric parameters during exercise and might therefore more adequately be used to separate normal from definitely abnormal responses to exercise.     

Assessment of aortocoronary bypass grafting using exercise ST segment/heart rate relation

The maximal rate of progression of ST segment depression relative to increases in heart rate (maximal ST/HR slope) has recently been shown to be an accurate index of the presence and the severity of coronary heart disease in patients with angina. The value of this new exercise test was assessed in patients undergoing aortocoronary bypass. The maximal ST/HR slope and the results of coronary angiography were obtained in each of 46 patients before aortocoronary bypass surgery and in 26 of the 46 patients six months after the operation. At each stage of the investigation the maximal ST/HR slope detected without false results the absence and the number of significantly diseased vessels as shown by angiocardiography. As in previous findings the ranges of the maximal ST/HR slope showed no overlap between the four groups of patients: those with no significant disease and those with single, double, or triple vessel disease. In each of the 46 patients in whom the maximal ST/HR slope was determined before operation and three months afterwards the slope was lower after operation than before, indicating improvement. Follow up examinations showed that the maximal ST/HR slopes accurately detected the number of patent grafts used to bypass significantly diseased coronary arteries. Furthermore, the development of a significant narrowing or occlusion in any vein graft caused an increase in the maximal ST/HR slope which was equivalent to the value of single vessel disease. It is suggested that the maximal ST/HR slope may be used reliably in individual patients to indicate restoration of adequate blood supply to the myocardium after successfully aortorcoronary bypass surgery and the to detect in the period of six months after the operation the degree of severity of coronary heart disease whether it is caused by occlusion of the graft of significant disease of the coronary arteries.