The effect of resting ST segment depression on the diagnostic characteristics of the exercise treadmill test

OBJECTIVES: The aim of this study is to demonstrate the effect of resting ST segment depression on the diagnostic characteristics of the exercise treadmill test. BACKGROUND: Previous studies evaluating the effect of resting ST segment depression on the diagnostic characteristics of exercise treadmill test have been conducted on relatively small patient groups and based only on visual electrocardiogram (ECG) analysis. METHODS: A retrospective analysis of data collected prospectively was performed on consecutive patients referred for evaluation of chest pain. One thousand two hundred eighty-two patients without a prior myocardial infarction underwent standard exercise treadmill tests followed by coronary angiography, with coronary artery disease defined as a 50% narrowing in at least one major epicardial coronary artery. Sensitivity, specificity, predictive accuracy and area under the curve of the receiver operating characteristic (ROC) plots were calculated for patients with and without resting ST segment depression as determined by visual or computerized analysis of the baseline ECG. RESULTS: Sensitivity of the exercise treadmill test increased in 206 patients with resting ST segment depression determined by visual ECG analysis compared with patients without resting ST segment depression (77 +/- 7% vs. 45 +/- 4%) and specificity decreased (48 +/- 12% vs. 84 +/- 3%). With computerized analysis, sensitivity of the treadmill test increased in 349 patients with resting ST segment depression compared with patients without resting ST segment depression (71 +/- 6% vs. 42 +/- 4%) and specificity decreased (52 +/- 9% vs. 87 +/- 3%) (p < 0.0001 for all comparisons). There was no significant difference in the area under the curve of the ROC plots (0.66-0.69) or the predictive accuracy (62-68%) between the four subgroups. CONCLUSIONS: The diagnostic accuracy and high sensitivity of the exercise treadmill test in a large cohort of patients with resting ST segment depression and no prior myocardial infarction support the initial use of the test for diagnosis of coronary artery disease. The classification of resting ST segment depression by method of analysis (visual vs. computerized) did not affect the results.     

提出和探讨新变量ST×t作为平板运动试验诊断标准的意义

目的提出新变量ST×t作为平板运动试验诊断冠心病标准并评价其临床意义。方法给76例患者在2周内分别做运动核素心肌显像和平板运动试验检查,依据自身对照设计原理,以三种平板试验阳性判定方法对每一例的平板试验结果进行分析。其中之一是新提出的以变量ST×t作为诊断标准的方法。并以运动核素心肌显像结果做对照, 计算三种评定方法对冠心病诊断的准确率、敏感性和特异性,并加以比较。结果以ST×t作为平板运动试验新的诊断标准,其准确率、敏感性和特异性高于或达到目前普遍使用的方法。结论以ST×t作为平板运动试验新的诊断标准,在操作上更为简便,优于传统的判定方法。     

平板运动试验致ST段抬高的临床意义

目的平板运动试验诱发ST段抬高的临床意义。方法比较平板运动试验中ST段抬高组与ST段压低组患者的冠状动脉造影结果。结果ST段抬高组和ST段压低组患者冠状动脉造影显示的血管狭窄程度及血管受累支数有显著差异(p<0.05)。结论平板运动试验诱发的ST段抬高是冠状动脉严重狭窄和痉挛所致心肌严重缺血损伤的表现。     

平板运动试验中室性早搏ST段下移诊断冠状动脉病变的价值

探讨平板运动试验中室性早搏(VPCs)ST段下移程度对反映冠状动脉(简称冠脉)病变的价值。将休息和平板运动试验中均发生VPCs并且在3个月内进行冠脉造影的92例患者按冠脉造影结果分成冠心病组和非冠心病组,比较两组VPCsST段下移程度,下移程度与冠脉狭窄程度的关系以及VPCsST段下移诊断冠心病的价值。结果:冠心病组运动中VPCsST段下移及ST/R均大于非冠心病组。其中ST/R>10%对冠心病诊断灵敏度为91%,特异度为75%;对单支、2支、3支血管病变诊断灵敏度分别为84%、91%、100%。冠脉狭窄≥90%组运动中VPCsST段下移和ST/R大于狭窄为50%~69%组。结论:运动试验中VPCsST段下移可作为诊断冠心病的有效参考指标,其下移程度可能与冠脉狭窄程度有关。     

平板运动试验时U波倒置的临床意义

目的 通过对比平板运动试验中U波倒置和ST段压低的发生情况,评价U波倒置对诊断冠心病的临床意义.方法 选择我院内科2011年8月～2013年2月心内科行平板运动试验检查的患者151例,其中男性76例,平均年龄57.9±5.16岁;女性75例,平均年龄55.4±7.09岁.对平板运动试验中出现的U波倒置和ST段下移进行对比研究和分析.结果 151例患者中,平板运动试验阳性55例,阴性96例;U波阳性33例,阴性118例.平板运动试验的阳性率36.4％,U波阳性率21.8％,卡方检验显示p=0.014;平板运动试验阳性的患者中冠脉造影阳性49例,阴性6例;U波阳性的患者中冠脉造影阳性27例,阴性6例.平板运动试验阻性的敏感性89.1％,U波阳性的敏感性81.8％,卡方检验显示p=0.578.结论 平板运动试验中U波倒置发生率较ST段下移发生率低,但冠脉造影确诊的冠心病患者中,U波倒置的敏感性和ST段下移相似,建议作为冠心病患者平板运动的阳性指标之一.     

Comparison of the electrocardiographic changes induced by maximam exercise testing with treadmill and cycle ergometer

Maximum exercise testing using treadmill walking and cycle ergometry was compared in 40 male patients who had suffered a myocardial infarction in the preceeding twelve months. Maximum oxygen uptake was on average 17% greater in the treadmill than the cycle test and maximum heart rate was also higher, but the rate pressure product (RPP) was a similar due to a higher blood pressure in the cycle ergometer test. Eleven subjects showe ST-segment depression greater than 1 min and eight subjects showed ST-segment elevation greater than 1 mm. There was a close relationship (r2 = 0.96) between the magnitude of ST-segment changes in the two tests. Four subjects showing ST depression of 1 mm in the treadmill test showed depression during the cycle ergometer test which was less than this conventionally "positive" value. In these subjects RPP was lower during cycling than in treadmill walking. With both tests maximum ST-segment changes were measured immediately on stopping exercise: resolution of ST depression was more rapid than ST elevation. The two exercise testing modes are closely comparable in their ability to reveal changes of myocardial ischemia.     

Efficacy of Terminalia arjuna in chronic stable angina: a double-blind,placebo-controlled,crossover study comparing Terminalia arjuna with isosorbide mononitrate

BACKGROUND: Terminalia arjuna, an Indian medicinal plant, has been reported to have beneficial effects in patients with ischemic heart disease in a number of small, open studies. The need for a double-blind, randomized, placebo-controlled study with adequate sample size has long been felt. The bark extract (IPC-53) contains acids (arjunic acid, terminic acid), glycosides (arjunetin arjunosides I-IV), strong antioxidants (flavones, tannins, oligomeric proanthocyanidins), minerals. etc. and exhibits antifailure and anti-ischemic properties. METHODS AND RESULTS: Fifty-eight males with chronic stable angina (NYHA class II-III) with evidence of provocable ischemia on treadmill exercise test received Terminalia arjuna (500 mg 8 hourly), isosorbide mononitrate (40 mg/daily) or a matching placebo for one week each, separated by a wash-out period of at least three days in a randomized, double-blind, crossover design. They underwent clinical, biochemical and treadmill exercise evaluation at the end of each therapy which were compared during the three therapy periods. Terminalia arjuna therapy was associated with significant decrease in the frequency of angina and need for isosorbide dinitrate (5.69+/-6.91 mg/week v. 18.22+/-9.29 mg/week during placebo therapy, p<0.005). The treadmill exercise test parameters improved significantly during therapy with Terminalia arjuna compared to those with placebo. The total duration of exercise increased (6.14+/-2.51 min v. 4.76+/-2.38 min, p<0.005), maximal ST depression during the longest equivalent stages of submaximal exercise decreased (1.41+/-0.55 mm v. 2.21+/-0.56 mm, p<0.005), time to recovery decreased (6.49+/-2.37 min v. 9.27+/-3.39 min, p<0.005) and higher double products were achieved (25.75+/-4.81x10(3) v. 23.11+/-4.83x10(3), p<0.005) during Terminalia arjuna therapy. Similar improvements in clinical and treadmill exercise test parameters were observed with isosorbide mononitrate compared to placebo therapy. No significant differences were observed in clinical or treadmill exercise test parameters when Terminalia arjuna and isosorbide mononitrate therapies were compared. No significant untoward effects were reported during Terminalia arjuna therapy. CONCLUSIONS: Terminalia arjuna bark extract, 500 mg 8 hourly, given to patients with stable angina with provocable ischemia on treadmill exercise, led to improvement in clinical and treadmill exercise parameters as compared to placebo therapy. These benefits were similar to those observed with isosorbide mononitrate (40 mg/day) therapy and the extract was well tolerated. Limitations of this study include applicability of the results to only men with chronic stable angina but not necessarily to women, as they were not studied.     

Relevance of simultaneous ST segment elevation and depression in an exercise treadmill test

Simultaneous ST segment elevation and depression recorded during an exercise treadmill test and its correlation with coronary angiogram is a new finding that does not find a place in medical literature. We conclude that in the presence of simultaneous ST segment elevation and ST segment depression during exercise treadmill test (1) the localizing value of isolated ST elevation is lost and (2) there is severe triple vessel disease warranting early intervention.     

Effects of Trimetazidine on Submaximal Exercise Test in Patients with Acute Myocardial Infarction

Background: It was demonstrated that the novel metabolic agent, trimetazidine, could lessen the incidence and severity of angina, whether used in monotherapy or combination. Although the animal studies demonstrated that trimetazidine reduces myocardial infarct size and improves recovery of mechanic function after ischemia, little is known on the potential benefits of trimetazidine in patients with acute myocardial infarction (AMI). The aim of this study was to evaluate the efficacy of trimetazidine on AMI by sub-maximal exercise test. Methods: A double-blind crossover trimetazidine versus placebo trial was carried out in 44 patients with AMI. Patients were randomly allotted into trimetazidine (23 patients) or placebo (21 patients) for 5 days and underwent an initial sub-maximal exercise test. Exercise tests according to the modified Bruce protocol were performed. Exercise end points included completion of stage II or 75% of maximum predicted heart rate whichever came first. An averaged 12-lead ECG was obtained at rest, every minute during exercise, at the onset of anginal symptoms, at the onset of 1-mm ST segment depression, at peak exercise and every 2-minute during recovery. After the initial exercise tests, study groups resumed the drugs in the opposite order for 4 to 5 days and underwent a second sub-maximal exercise test. Results: Exercise induced ST segment depression was noted in 17 patients (38.6%) receiving placebo. However, exercise induced ST-segment depression was observed in 8 patients (18.1%) taking TMZ. Positive exercise test results were significantly higher in placebo group than TMZ group (p = 0.018). Additionally, trimetazidine prolonged the time to 1-mm ST-segment depression (6.1 ± 0.5 vs 4.9 ± 0.4, p < 0.031) and exercise duration (7.2 ± 0.9 vs 5.8 ± 0.9, p < 0.025). Conclusion: Trimetazidine therapy improves the exercise capacity and reduces evidence of ischemia derived from sub-maximal post-infarction exercise testing.     

踏板运动试验对评估冠状动脉狭窄严重程度的意义

为明确踏板运动试验与冠状动脉狭窄程度的关系,选取115例冠状动脉造影阳性、且于造影前或造影后1周作踏板运动试验的患者,观察以直径法确定的冠状动脉狭窄程度和范围与踏板运动试验结果对比.结果显示:踏板运动试验中ST段压低出现越早、ST段压低程度越大、持续时间越长、出现ST段压低的导联数目越多,冠状动脉狭窄越重.冠状动脉造影阳性而踏板运动试验阴性者,多为单支或轻度病变.认为踏板运动试验可初步估测冠状动脉狭窄程度.     

Absence of ST elevation in ECG leads V7, V8, V9 in ischaemia of non-occlusive aetiologies

BACKGROUND AND OBJECTIVE: Occlusion of the circumflex coronary artery may present with either ST elevation typical of inferior or lateral myocardial infarction, ST depression or a normal 12-lead electrocardiogram (ECG). In patients presenting with ST depression, concomitant ST elevation in the posterior leads V7, V8 and V9 is believed to reflect ST-elevation myocardial infarction of the posterior wall. However, to be confident of this diagnosis, it is necessary to know that posterior ST depression does not occur in acute subendocardial ischaemia. METHODS AND RESULTS: We have prospectively recorded leads V7, V8 and V9 simultaneously with the standard 12-lead ECG in patients who underwent treadmill stress test. Group A consists of 35 patients who showed ischaemic praecordial ST depression in their 12-lead ECGs during treadmill stress test and subsequent angiographic documentation of significant coronary artery disease. Group B consists of 35 subjects who showed normal ECG findings during treadmill stress test. In none of the Group A or B patients was there ST elevation in leads V7, V8 or V9 either at rest or at peak exercise. ST depression was seen in 69% in V7, 31% in V8 and 11% in V9 in the Group A patients at peak exercise. CONCLUSION: ST elevation in leads V7, V8 and V9 is uncommon in patients presenting with subendocardial ischaemia. Therefore, in patients presenting with acute chest pain and ST depression in the 12-lead ECG, concomitant posterior ST elevation may be a reliable indicator of ST elevation posterior MI. This is likely due to circumflex artery occlusion and may require thrombolytic therapy.     

The effect of hypolipemic therapy with diet and simvastatin on the course of angina pectoris and the results of exercise stress test in patients with coronary artery disease

Statins are the multi-directorial acting drugs in atherosclerosis prevention, which decrease the overall and cardiovascular mortality. The aim of this study was to estimate the effect of six-month long hypolipemic therapy with diet and 20 mg of simvastatin on clinical intensity of angina pectoris and the course of exercise stress test. Patients and methods: We studied 44 patients with typical anginal chest pain. In all blood sampling and treadmill stress test were made, and next in all hypolipemic diet and simvastatin 20 mg were recommended. After four weeks and six months of treatment clinical assessment and exercise test were made. Results: After four weeks and six month long observation period the decrease of total and LDL cholesterol, triglycerides and fibrinogen were found. Moreover, we have observed the improvement in frequency of anginal symptoms, their intensity in CCS classification and number of nitroglycerin tablets taken per week. The course of exercise test was also ameliorated: the percentage of patients, in whom stress test was finished because of chest pain was decreased, time of chest pain duration after exercise cessation was shorter, the percentage of patients with significant ST interval depression diminished, maximal ST interval depression as well as the time of significant ST interval depression duration also decreased. Although improvement in values of mentioned parameters, after six months long therapy with simvastatin the percentage of patients with Duke's treadmill score value showing intermediate cardiovascular risk (between -10 and +4) increased. In conclusion, therapy with hypolipemic diet and simvastatin already after four weeks decreased plasma lipids and fibrinogen levels and improved the course of angina pectoris and exercise stress test, what suggested its effectiveness not only as the treatment improving atherosclerosis risk factors, but also with prompt and clinical important effect ameliorating the handicapped coronary reserve.     

Attenuation of exercise-induced ST depression during combined isometric and dynamic exercise in coronary artery disease

ST-segment depression was measured during submaximal dynamic (treadmill) and combined isometric-dynamic (isodynamic) exercise at comparable rate-pressure products in 11 patients (mean age 63 years) with stable coronary artery disease who were participating in an exercise training program. Each patient completed 3 separate trials. Trial 1 (baseline) was a submaximal treadmill exercise test to determine the threshold heart rate-systolic blood pressure (rate-pressure product) for ST-segment depression (greater than or equal to 1.0 mm). During trials 2 and 3, patients performed (in random order) dynamic treadmill exercise and isodynamic exercise (treadmill walking 1.5 to 2.0 mph carrying 15 to 25 kg) until threshold rate-pressure product was achieved. During trial 1, each patient showed significant ST depression (mean 1.7 mm) at target rate-pressure product (mean 18,200). Subsequent dynamic exercise trials 2 and 3 showed similar mean ST depression (1.5 mm) and rate-pressure product (18,000). During isodynamic exercise trials 2 and 3, subjects showed only minimal ST depression (mean 0.4 mm) at a rate-pressure product similar to dynamic exercise (mean 18,590). Heart rates were significantly lower (-10/min) and systolic (+20 mm Hg) and diastolic (+25 mm Hg) pressure was higher during isodynamic exercise (p less than 0.05). The rate-pressure product is not a valid index of ST response during isodynamic exercise in stable exercise-trained cardiac patients. Attenuation of ST depression during isodynamic exercise may be attributed to a combination of increased diastolic perfusion pressure, decreased heart rate and possibly to reductions in venous return and ventricular diastolic wall tension due to increased intrathoracic and abdominal pressure.     

Clinical studies with transdermal nitroglycerin

The short- and long-term effects of various Nitro-Dur formulations on performance and hemodynamics were studied in 15 men with stable angina pectoris who also had a positive treadmill exercise test. A treadmill exercise score (TES) was used that quantified the “ischemic” ST segment response to exercise. The score incorporated information that reflected the rapidity of evolution of ST segment depression during exercise and the time required for it to resolve after cessation of exercise. In early tests (n = 10) Nitro-Dur improved both the TES (by 31%: p < 0.0001) and the time required for 1 mm ST segment depression (by 33%: p < 0.0001). At all dosage levels, Nitro-Dur also decreased resting systolic blood pressure and increased resting heart rate. No dose-response patterns emerged. Changes in TES and time to ST segment depression were greater with sublingual nitroglycerin than they were with Nitro-Dur. In tests conducted after prolonged dosage (n = 5), the effects of Nitro-Dur on blood pressure and heart rate became attenuated at weeks 2 and 4, although cardiac responsiveness was preserved, as reflected in the increased time required before the occurrence of 1 mm ST segment depression. The latter effect was also observed with sublingual nitroglycerin. The clinical relevance of these data to the design of individual patient therapy is discussed.     

Comparison of clinical and treadmill variables for the prediction of outcome after myocardial infarction

To assess the relative prognostic merits of 15 clinical and 10 predischarge exercise test variables, 226 patients who had sustained an acute myocardial infarction were studied. A submaximal treadmill test was performed on 205 patients to a mean work load of 5.7 +/- 2.9 METS. Testing was performed an average of 11.7 (range 6 to 33) days after myocardial infarction. During the first year of observation, major cardiac events were noted in 33 patients (16%), unstable angina in 7 (3.4%), recurrent myocardial infarction in 14 (6.8%) and death in 12 patients (5.9%). Cardiac mortality correlated with mean peak serum creatine kinase (CK) (p less than 0.05), history of previous myocardial infarction (p less than 0.01) and ST segment depression at rest (p less than 0.01). The only exercise variable that correlated with cardiac mortality was poor exercise endurance (p less than 0.05). Multivariate risk stratification of clinical and treadmill variables from these 205 patients using linear discriminant analysis produced a function that correctly classified 95% of those who were event-free and 80% of those who died. The first four discriminant variables that contributed independent information for the prediction of cardiac mortality were: 1) ST segment depression at rest; 2) CK greater than 1,280 IU/liter; 3) exercise duration less than 3 minutes; and 4) a history of previous myocardial infarction. ST segment depression on the predischarge treadmill test did not predict any event, nor did it improve the predictive accuracy of the clinical variables. It is concluded that a history of previous myocardial infarction and ST segment depression on the rest electrocardiogram indicate a poor prognosis after acute myocardial infarction. Poor endurance is the only exercise variable that suggests a future cardiac event. Prognosis after acute myocardial infarction is more accurately predicted by these clinical data than by variables derived from the predischarge treadmill test.     

Comparison of the ST/heart rate slope with the modified Bruce exercise test in the detection of coronary artery disease

The rate of depression of the ST segment with increasing heart rate (HR) during exercise has been claimed to predict the extent of coronary artery disease (CAD). To determine whether the maximal ST/HR slope is better than the Bruce treadmill exercise test for predicting the presence of CAD, the maximal ST segment/HR slope was calculated in 81 patients and compared with the results of a standard 12-lead exercise test. In 21 patients (26%), the ST/HR slope could not be calculated. In 60 patients with ST/HR slope values, the extent of CAD was predicted in 24 patients (40%). The sensitivity and specificity of the ST/HR slope in predicting the presence of CAD in the 60 patients with slope values were 91% and 27%, respectively. The sensitivity and specificity of the modified Bruce treadmill exercise test in the 81 patients were 81% and 64%, respectively. Thus, the use of the ST/HR slope does not provide additional information that cannot be obtained using the standard Bruce exercise test.     

心脏活动平板运动试验参数对冠心病的诊断价值

目的 总结平板运动试验对冠心病的诊断价值.方法 2006年1月至2011年3月在我院住院接受心脏活动平板运动试验（TET）及冠状动脉造影（CAG）检查的患者445例,回顾性总结分析其平板运动试验中不同参数变化对冠心病的诊断价值.结果 ①进行平板运动试验的445例患者中,TET阳性200例,其中CAG阳性150例、CAG阴性50例;TET阴性245例,其中CAG阴性206例、CAG阳性39例.TET检出冠心病的敏感性为79.36%（150/189）,特异性为80.47%（206/256）,预测准确性为80.00%（356/445）.②CAG阳性组（189例）与CAG 阴性组（256例）比较,CAG阳性组的总运动时间、峰值心率、ST段下移出现时间明显小于CAG阴性组（P＜0.05）,其ST段下移幅度及持续时间显著大于CAG阴性组（P＜0.05）.③CAG阳性的189例中,单支病变87例、多支病变102例,多支病变组总运动时间、峰值心率、ST段下移出现时间明显小于单支病变组（P＜0.05）,ST段下移幅度及持续时间显著大于单支病变组（P＜0.05）.④在平板运动试验阳性组中,性别在冠心病的诊断价值中差异有统计学意义,男性对冠心病的诊断率明显高于女性（P＜0.05）;在平板运动试验阴性组中,性别在冠心病的诊断率方面差异无统计学意义（P＞0.05）.⑤平板运动试验Bruce方案级别与冠心病也有明显的相关性：1级的阳性预测值、阴性预测值和准确率均较其他级高,分别为85.71%、94.44%和88.33%.随着级别的递增,到4级时,其阴性预测值达100%,准确率也为100%.结论 平板运动试验是一项诊断冠心病较理想的非创伤性的检查方法,综合多项参数分析可初步估测其病变程度.     

Mechanism of exercise-induced ST depression based on hemodynamics during cardiac catheterization

OBJECTIVES: The cause of exercise-induced ST depression was studied by assessing left ventricular end-diastolic pressure (LVEDP). METHODS: This study included 28 patients with normal coronary artery, 24 patients with vasospastic angina pectoris and 28 patients with fixed organic lesion who underwent both treadmill exercise testing and selective coronary arteriography. Exercise-induced ST deviation was considered as maximal ST deviation during the exercise test and maximum LVEDP was considered as the pressure measured 1 min after left ventriculography. RESULTS: The degree of exercise-induced ST depression in aVF showed no significant differences between the three groups. Exercise-induced ST elevation occurred in the intracardiac leads and exercise-induced ST depression occurred in the epicardial leads. These electrocardiographic changes were not contradictory to subendocardial ischemia. In addition, there was a good correlation (r = - 0.465, p < 0.01) between exercise-induced ST depression and maximum LVEDP elevation. CONCLUSIONS: Exercise-induced ST depression was caused by subendocardial ischemia due to increased LVEDP.     

Relation between duration and intensity of first exercise and "warm up" in ischaemic heart disease

OBJECTIVE—To determine the importance of the duration and intensity of "warm up" exercise for reducing ischaemia during second exercise in patients with exertional angina.
DESIGN—Randomised crossover comparison of three warm up exercise protocols.
PATIENTS—18 subjects with stable ischaemic heart disease and > 0.1 mV ST segment depression on treadmill exercise testing.
INTERVENTIONS—The warm up protocols were 20 minutes of slow exercise at 2.7 km/h, symptom limited graded exercise for a mean of 7.4 (range 5.0 to 10.5) minutes, and three minutes of symptom limited fast exercise of similar maximum intensity.
MAIN OUTCOME MEASURES—ST segment depression during graded treadmill exercise undertaken 10 minutes after each warm up protocol or no warm up exercise.
RESULTS—Compared with exercise with no warm up, the duration of graded exercise after earlier slow warm up increased by 4.9% (95% confidence interval (CI), −3.3% to 13.7%), after graded warm up by 10.3% (95% CI, 5.6% to 15.2%), and after fast warm up by 16% (95% CI, 6.2% to 26.7%). ST segment depression at equivalent submaximal exercise decreased after slow warm up by 27% (95% CI, 5% to 44%), after graded warm up by 31% (95% CI, 17% to 44%), and after fast warm up by 47% (95% CI, 27% to 61%). Compared with slow warm up exercise, the more intense graded and fast warm up protocols significantly increased the duration of second exercise (p = 0.0072) and reduced both peak ST depression (p = 0.0026) and the rate of increase of ST depression (p = 0.0069).
CONCLUSIONS—In patients with exertional angina the size of the warm up response is related to the maximum intensity rather than the duration of first exercise.


     

Treadmill Exercise Testing in the Presence of Digitalis Therapy or Nonspecific ST-T Changes: Correlation with Coronary Angiography

Treadmill exercise test results were studied in 93 patients with chest pain who had received digitalis therapy or had nonspecific ST-T changes in the resting electrocardiogram. Results of the treadmill test were correlated with the findings of coronary angiography. A positive treadmill result was defined as horizontal or down-sloping ST segment depression greater than or equal to 1.0 mm. Of the 40 patients with no or insignificant coronary artery disease, 15 had taken digitalls; 4 of the 15 demonstrated a positive response on the treadmill test. Of the 53 patients with coronary artery disease, 21 had taken digitalis; 15 of the 21 displayed a positive response. Among the remaining 32 not on digitalis, 20 had a positive response. The specificity of the treadmill exercise test was 96% in patients with coronary artery disease not on digitalis and whose resting electrocardiogram showed nonspecific ST changes. The specificity of the treadmill test in patients who had received digitalis was 73%. Sensitivity was 63% and 71%, respectively. By utilizing more stringent criteria in the interpretation of the treadmill exercise test (greater than or equal to 1.5 mm ST depression), among the patients on digitalis only 6.7% (1/15) with normal coronary arteries and 48% (10/21) with coronary artery disease had a positive response. With the use of the latter criterion the test was specific in 93% (14/15) of the patients and is usually indicative of coronary artery disease.