Accuracy of exercise electrocardiography in detecting physiologically significant coronary arterial lesions

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.     

Unstable coronary artery disease in post-menopausal women. Identifying patients with significant coronary artery disease by basic clinical parameters and exercise test

Background The diagnostic information from an ECG taken while at rest andan exercise test is considered less reliable in women than inmen, mostly due to a high percentage of false-positive tests.This can be explained by a lower pre-test likelihood of coronaryheart disease. Aims To evaluate the diagnostic information that can be gained frombasic clinical parameters, an ECG and exercise test in a groupof post-menopausal women with symptoms of unstable coronaryartery disease in order to identify patients with significantcoronary artery stenoses. Methods and Results We prospectively studied 200 post-menopausal women admittedto the coronary care unit with symptoms of unstable coronaryartery disease and ECG changes suggestive of ischaemia. Thediagnostic value of common risk factors, myocardial enzymesand an early exercise test were assessed. A coronary angiogramwas performed within 60 days. Median age was 67 years. On admission,38% had ST depression on an ECG taken while at rest, 76% hadT-wave inversion, and 41% increased enzyme levels. The coronaryangiogram revealed that 15% had no atherosclerosis, 14% hadatherosclerosis but no lesion 50% of luminal diameter and 71%had at least one significant stenosis. Of patients with knownindicators of atherosclerotic disease, all but one had atherosclerosisvisualized on the coronary angiogram. A relative ST depression0·1mV and a low maximum workload at exercise test werestrong predictors of significant coronary artery disease. Thepositive predictive value of ST depression was 91% and of lowmaximum workload 84%. Conclusion In post-menopausal women with signs of unstable angina and ischaemiaon an ECG taken while at rest, the prevalence of coronary atherosclerosisis high, 85%. Contrary to earlier studies, ST T-changes at theearly exercise test had a high positive predictive value, especiallyin combination with a low maximum workload with no false-positiveresults.     

Value of arm exercise testing in detecting coronary artery disease

Alternative methods of exercise testing are needed for patients with vascular, orthopedic or neurologic conditions who cannot perform leg exercise. To determine the sensitivity of arm exercise in detecting coronary artery disease (CAD), 30 patients with angina pectoris performed both arm ergometry and treadmill testing before coronary angiography. All patients had at least 70% diameter reduction in 1 or more major coronary arteries. Ischemic ST depression (greater than or equal to 1 mm) or angina occurred more frequently (86%, 26 patients) with leg exercise than with arm exercise (40%, 12 patients). There was no significant difference in peak rate-pressure product achieved with either test, although the peak oxygen consumption was greater during leg exercise than during arm exercise (18 vs 13 ml/kg/min, respectively, p less than 0.001). For concordantly positive tests, the oxygen consumption at onset of ischemia was significantly lower during arm testing than during leg testing (12 vs 17 ml/kg/min, respectively, p less than 0.001). There was no significant difference in heart rate during either test at onset ischemia. Thus, arm exercise testing is a reasonable, but not equivalent, alternative to leg exercise testing in patients who cannot perform leg exercise.     

Accuracy of dobutamine stress echocardiography in detecting coronary artery disease.

The diagnostic accuracy of dobutamine stress echocardiography (DSE) (incremental infused doses of 5, 10, 20 and 30 micrograms/kg/min) was evaluated in 141 patients who underwent coronary arteriography within 2 weeks of DSE. All patients were being evaluated for known or suspected coronary artery disease (CAD). DSE was interpreted blindly as normal or showing evidence of CAD, depending on the presence of resting or inducible wall motion abnormalities. Coronary arteriograms were reviewed in a blinded, quantitative fashion. DSE had a sensitivity of 96% for detecting patients with CAD, and a specificity of 66%. For the 53 patients with normal resting wall motion, sensitivity was 87% and specificity 91%. The protocol was well-tolerated by all patients. In comparison with wall motion analysis, 12-lead electrocardiograms during dobutamine infusion revealed ischemic changes in only 17% of patients with CAD. It is concluded that DSE is a clinically useful and accurate means for detecting CAD, its specificity is hindered in patients with resting wall motion abnormalities, and it can safely be used in patients with known cardiac disease.     

运动试验阳性无冠状动脉病变者血流动力学变化的临床意义

目的探讨运动试验阳性但无显著冠状动脉病变患者血流动力学变化的临床意义。方法选取因发作性胸痛症状拟诊冠心病入院,选择性冠状动脉造影正常,左心室射血分数超过0．55的病人85例,根据次极量踏车运动试验(Bruce方案)结果,分为运动试验阳性组58例与阴性组27例,分析两组间升主动脉脉压(pulse pressure,PP)与脉压指数(pulse pressure index,PPI)、左心室舒张末压(left ventricular end diastolic pressure,LVEDP)及左心室舒张末压指数(left ventricular end diastolic pressure index,LVEDPI) 等血流动力学指标变化的临床意义。结果①运动试验阳性与阴性组间的病人一般资料如年龄、性别、是否伴有高血压及左心室射血分数差异无统计学意义(P>0．05);②升主动脉PP与PPI在两组间差异无统计学意义(P>0．05);③LVEDP在运动试验阳性组显著高于阴性组(P<0．01),而LVEDPI则前者显著低于后者(P<0．01)。结论有胸痛症状而选择性冠状动脉造影正常者,PP或PPI指标并不能反映其冠状动脉血流储备,同时伴有LVEDP增加者易出现运动试验阳性,提示X综合征者的LVEDP增加可能与心内膜下心肌缺血有关,LVEDPI较LVEDP反应可能更为敏感。     

Diagnostic value of the cardiopulmonary exercise test in coronary artery disease

BackgroundCoronary angiography (CAG) is “gold standard” for the diagnosis of coronary heart disease (CHD). This study aimed to explore the diagnostic value of cardiopulmonary exercise testing (CPET) and the oxygen uptake kinetics indexes of CPET.MethodsOne hundred thirty-one patients with chest pain who underwent coronary angiography in the Department of Cardiology of our hospital from April to September 2021 were selected. According to the results of angiography, the patients were divided into an observation group (patients with coronary heart disease, n=80) and a control group (patients without coronary heart disease, n=75). Both groups underwent CPET before angiography. The differences of peak oxygen uptake, anaerobic threshold, peak kilogram oxygen uptake, peak oxygen pulse, maximum exercise load, maximum metabolic equivalent, and exercise time between the two groups were compared. Also, the correlation between the above indexes and the degree of coronary artery stenosis was analyzed, and the clinical value of the CPET in the diagnosis of CHD was evaluated.ResultsThe peak oxygen uptake, anaerobic threshold, peak kilogram oxygen uptake, peak oxygen pulse, maximum exercise load, maximum metabolic equivalent, and exercise time in the observation group were lower than those in the control group (P<0.01), and were negatively correlated with the Gensini score (P<0.01). The area under the receiver operating characteristic (ROC) curve of the above seven indexes in the combined diagnosis of CHD was 0.974, the sensitivity was 86.40%, and the specificity was 98.50%, which was better than the clinical value of any of the above indexes alone.ConclusionsCPET is an effective non-invasive examination in the diagnosis of CHD, and has a certain clinical value in the evaluation of the severity of coronary artery stenosis.     

平板运动试验诊断冠心病的临床价值

目的通过与冠脉造影（CAG）结果对比,探讨运动平板试验（TET）对冠心病的诊断价值。方法以CAG为诊断冠心病（冠脉狭窄≥50%）的＂金标准＂,对同期先后行TET和CAG检查的150例疑似冠心病患者进行回顾性分析,将其TET的结果与CAG进行比较。结果 TET检出冠心病的敏感性80.5%,特异性63.3%,准确性为72.7%,阳性预测值为72.5%,阴性预测值72.9%。冠心病患者中TET诊断阳性率与病变血管支数无明显相关性（r=0.482,p=0.68）,TET诊断结果阳性与阴性仅与血管狭窄程度≥75%狭窄的节段数目有统计学差异（p〈0.05）。结论 TET检出冠心病的特异性较低,但敏感性较高,能较准确评价冠心病的缺血情况。     

Cardiopulmonary exercise test evidence of isolated right coronary artery disease

Isolated right coronary artery disease is usually difficult to diagnose because of frequent negativity of standard exercise stress test. We report a case of isolated coronary artery stenosis which was not detected by standard ECG stress testing. The cardiopulmonary exercise test showed a peculiar pattern: abrupt flattening in VO2/Work relationship, plateau in O2 pulse and 90 s afterwards a plateau in heart rate, probably related to vagal afferent stimulation by ischaemia of the postero-inferior wall of the left ventricle. Multidetector computed tomography of coronary vessels and coronary angiography confirmed isolated critical stenosis of middle right coronary artery. After revascularization by PTCA, normalization of cardiopulmonary exercise test was obtained.     

Quantitative thallium-201 imaging: Limitations in detecting pathophysiologically significant obstructive coronary artery disease

Washout of thallium-201 after stress testing has been proposed as a method of detecting abnormal zonal myocardial perfusion without relating it to a reference “normal” area. Therefore, 18 patients with single-vessel coronary artery disease, undergoing percutaneous transluminal coronary angioplasty, underwent maximum stress testing and thallium imaging. A myocardial perfusion defect was seen in the immediate postexercise images in all 19 zones (one patient studied twice) supplied by the vessel with the obstructive lesion. Delayed images showed improvement in 15 of the 19 segments. Of the four zones which did not improve, three had evidence of a prior nontransmural myocardial infarction. Quantitative analysis of washout curves showed that counts decreased in 17 of 19 zones after background subtraction and in all 19 zones if background was not subtracted. In the corresponding normal zones directionally similar decreases in counts were seen. Thus washout characteristics were similar for both diseased and normal zones. These data indicate that washout curves are limited in their ability to detect the presence of a physiologically significant lesion.     

The cardiokymography exercise test compared to the thallium-201 perfusion exercise test in the diagnosis of coronary artery disease

To determine the usefulness of exercise cardiokymography (CKG) compared to thallium-201 perfusion scanning in the diagnosis of coronary artery disease (CAD), 179 patients with a mean age of 54 +/- 10 years (73% men) were studied. Previously documented CAD was present in 73 patients (41%); 13 (7%) were asymptomatic and 93 (53%) had chest pain syndrome. Exercise stress testing, CKG, and thallium-201 perfusion scanning were independently correlated with coronary angiographic data. Treadmill exercise stress test alone without CKG had a sensitivity of 68% and specificity of 62%. CKG showed a sensitivity of 76% and a specificity of 90%, and easily interpreted cardiokymograms were obtained in 78% of patients studied. Thallium-201 scans had a sensitivity of 79% and a specificity of 88%. However, when the CKG and treadmill exercise test results were concordant (both positive or both negative), the CKG exercise test had a sensitivity of 87% and specificity of 100%. Thus, when the CKG and exercise test results are concordant, the sensitivity and specificity are equal to or better than thallium-201 perfusion scanning for the prediction of CAD. Since CKG is an inexpensive and noninvasive test, its adjunctive use with routine exercise stress testing may be of great value.     

Evaluation of the exercise test in patients with angiographically documented coronary artery disease

100 male patients with at least 75% obstruction of one or more coronary arteries were subjected to submaximal exercise tests. Among the 73 subjects who had positive tests, 92% of those with one-vessel obstruction had an ST depression of 1 mm, none having more than 2 mm; by contrast, 44% of those with three-vessel disease had an ST depression of more than 2 mm and only 27% on ST depression of 1 mm. Left-ventricular end-diastolic pressure exceeded 15 mm Hg in 86% of the patients who had an ST depression of more than 2 mm but only in 33% of those with a depression of 1 mm; impaired contractility was found in 81% of the former and in 36% of the latter. 92% of those with one-vessel obstruction were able to perform work of 75 and 100 W/min while only 25% of those with three-vessel disease were able to perform the same amount of work. The peak exercise heart rate and systolic blood pressure also decreased with the increase in the number of affected vessels.     

Estimating the likelihood of significant coronary artery disease

Among 23 clinical characteristics examined in 3,627 consecutive, symptomatic patients referred for cardiac catheterization between 1969 and 1979, nine were found to be important for estimating the likelihood a patient had significant coronary artery disease. A model using these characteristics accurately estimated the likelihood of disease when applied prospectively to 1,811 patients referred since 1979 and when used to estimate the prevalence of disease in subgroups reported in the literature. Since accurate estimates of the likelihood of significant disease that are based on clinical characteristics are reproducible, they should be used in interpreting the results of additional noninvasive tests and in quantitating the added diagnostic value.     

Right ventricular systolic function during exercise with and without significant coronary artery disease

To evaluate the effects of exercise and coronary artery disease on right ventricular (RV) systolic function, rest and exercise biplane RV angiograms were recorded in 20 patients undergoing diagnostic cardiac catheterization. Thirteen patients had exercise angiograms of sufficient quality to undergo analysis and were classified into 2 groups. Group 1 had no or only mild coronary artery disease; group 2 had significant coronary artery disease as manifested by new, exercise-induced, left ventricular regional wall motion abnormalities. RV systolic pressure increased in both groups during exercise: 33 to 57 mm Hg in group 1 (p = 0.0002) and 33 to 55 mm Hg in group 2 (p = 0.0004). Pulmonary resistance did not change in group 1 during exercise but increased in group 2 (3.2 to 4.8 Wood units, p = 0.04). RV ejection fraction increased slightly, but not significantly, during exercise in group 1, but decreased in group 2 (73 vs 58% with exercise [p = 0.01]). The change in RV ejection fraction from rest to exercise correlated closely with the change in pulmonary resistance from rest to exercise (r = -0.89, p less than 0.0001). RV regional wall motion analysis demonstrated a generalized decline in regional ejection fraction in group 2 during exercise, even in patients without right coronary artery disease. In conclusion, there is a decline in RV ejection fraction during exercise in patients with significant coronary artery disease. The generalized reduction in regional RV ejection fraction coupled with the close correlation with the change in pulmonary resistance suggests that increased afterload, rather than RV ischemia, is the cause.     

平板运动试验假阳性相关因素的分析

目的 探讨活动平板运动试验假阳性相关影响因素,调整观察参数,提高心电图活动平板运动试验评估冠脉病变的价值.方法 收集整理2012年1月至2014年6月因疑似冠心病在苏州九龙医院心脏中心接受活动平板运动试验、结果阳性的94例患者,所有患者均在平板运动试验后1w内行冠脉造影检查.根据造影结果将其分为真阳性组(A组)和假阳性组(B组),对比分析两组各项临床资料及活动平板试验数据.结果 真阳性组和假阳性组在性别、最大运动耐量(Mets)、运动峰值、心率收缩压乘积方面有显著差异(p＜0.05),A组平板运动试验中最大心率与运动终止后2 min心率的差值显著低于B组;A组平板运动试验终止后3 min收缩压与运动终止1 min收缩压的比值、包含2个以上冠心病危险因子的例数明显大于B组(p＜0.05).结论 活动平板试验参数结合相关的临床资料、血流动力学相关参数,能提高冠脉病变的诊断准确性,对临床诊断冠心病、评估治疗效果和预后等方面可提供有价值的参考.     

Accuracy of systolic time intervals in detecting abnormal left ventricular performance in coronary artery disease

Sixty-six consecutive patients with a history of previous myocardial infarction and 48 patients with angina pectoris without evidence of previous myocardial infarction, all of whom had diagnostic coronary arteriography and left ventriculography, were studied in a prospective analysis of the accuracy of noninvasively determined systolic time intervals as a measure of global left ventricular performance. Forty-one patients who were evaluated for atypical chest pain and found to have normal coronary arteries and left ventricular performance served as control subjects. Six methods of statistical analysis were employed in assessing the accuracy of systolic time intervals in relation to the left ventricular ejection fraction: (1) analysis of variance, (2) cumulative distribution analysis, (3) correlation, (4) sensitivity and specificity, (5) percent agreement, and (6) logistic regression analysis. These tests permitted comparison between the systolic time intervals and the angiographic left ventricular ejection fraction. Analysis of variance revealed identical discriminating power for the ratio of the preejection period to left ventricular ejection time (PEP/ LVET) and left ventricular ejection fraction in separating the normal group and patients without previous myocardial infarction from the patients with previous myocardial infarction. The preejection period and left ventricular ejection time corrected for heart rate were less discriminating than left ventricular ejection fraction or PEP/LVET. The cumulative distribution plots for the left ventricular ejection fraction and PEP/LVET in the three groups of patients were remarkably similar. The correlation of PEP/LVET and left ventricular ejection fraction for all three groups of patients was 0.84. The sensitivity and specificity of the PEP/LVET in relation to the left ventricular ejection fraction were 88 and 96 percent, respectively. The overall agreement between the two measures in detecting the prevalence of abnormality in global left ventricular performance in subgroups of patients was 92 percent. By logistic regression analysis the two measures had equal capacity in discriminating the patients with previous myocardial infarction from the control group.The multiple strategies of comparison employed in this study document the close relation of measures of the timing of the left ventricular contraction cycle by systolic time intervals and estimates of the extent of left ventricular contraction by ejection fraction in patients with coronary artery disease. It is concluded that these measures afford independent and complementary methods of defining the presence of abnormal left ventricular performance in the resting supine patient with coronary artery disease.