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Exercise testing in congenital aortic stenosis.

Treadmill exercise testing was performed on 23 patients with isolated congenital aortic stenosis. It was found that eight patients, with a negative exercise test and a normal rise in systolic blood pressure on exercise, had gradients less than 45 mmHg. Fifteen patients with gradients greater than 50 mmHg had positive exercise tests and their systolic blood pressure did not rise normally. It is suggested that the left heart studies to measure aortic valve gradients can safely be postponed if an exercise test is negative. Serial exercise testing of such patients will give an indication when left heart catheterization should be considered.

Adolescent

Detection of ventricular ectopy in patients with coronary heart disease and normal subjects by exercise testing and ambulatory electrocardiography.

Maximal exercise testing and 24-hour ambulatory electrocardiographic recording (Holter monitor) were utilized in the detection of ventricular ectopy in 90 patients with stable chronic coronary heart disease and in 30 normal subjects. Although the occurrence of any ventricular ectopic activity, as detected by either or both methods, was common, the incidence was significantly higher (P less than 0.001) in patients with coronary heart disease (86 percent; 77/90), as compared to that in normal subjects (40 percent; 12/30). Ventricular arrhythmia was more frequently detected by the 24-hour continuous electrocardiographic recording, being found in 70 of the 90 patients with coronary heart disease and in ten of the 30 normal subjects. In comparison, exercise testing disclosed ventricular ectopy in 56 of the 90 patients with coronary heart disease and in two of the 30 normal subjects. Multiform and repetitive patterns of ventricular ectopy were detected twice as commonly by continuous electrocardiographic recording than with exercise testing, and these patterns were present in one-half of the patients with coronary heart disease. Both methods of examination adjunctively disclosed more ventricular ectopy than either method alone.

Angina Pectoris

[The clinical significance of the low level treadmill exercise test in acute myocardial infarction].

To clarify the clinical significance of the exercise test in acute myocardial infarction (AMI), the relationship between the results of exercise test and clinical features was studied. The low level treadmill exercise test (maximum exercise time was 1080 seconds and the maximum oxygen consumption was 7 METs) were performed in 111 patients within 2 months after the onset of AMI. The exercise time, the endpoint of the exercise test, the exercise-induced ST-segment deviation and ventricular premature beats (VPC) were evaluated from the exercise tests. Among the clinical features, age, sex, the severity in the acute period (Killip's classification and Forrester's hemodynamic subset), the findings in cardioangiography (the number of diseased coronary arteries, left ventricular ejection fraction and abnormal wall motion in the left ventricle) and short term prognosis after AMI were evaluated. The prognosis was judged as poor when cardiac death, congestive heart failure, postinfarction angina, the decrease of exercise tolerance and reattack of AMI occurred, or when an aorto-coronary bypass graft or percutaneous transluminal coronary angioplasty was performed. The exercise time was shorter in patients over the age of 60 years (578 +/- 360 seconds) than in younger patients (818 +/- 296 seconds), and also in females (487 +/- 392 seconds) than in males (767 +/- 319 seconds). The patients classed as Forrester's hemodynamic subset IV had shorter exercise time than the others. But, there was no relationship between the exercise time and Killip's classification. Low left ventricular ejection fraction (55% or less) was associated with short exercise time and the apperance of exercise-induced VPC. But the number of diseased coronary artery and abnormal wall motion in the left ventricle were not related to the exercise test. The patients with high exercise tolerance (4.2 METs or more) in the AMI recovery period showed better prognosis than those with low exercise tolerance within one year after AMI (96% vs 50%, p less than 0.0001, respectively). In conclusion, the low level exercise test in AMI was influenced by age, sex and cardiac function, and it was useful in evaluating the short term prognosis after AMI.

Adult

Respiratory gas exchange during treadmill exercise testing: reproducibility and comparison of different exercise protocols.

Ten subjects performed 4 maximal exercise tests to evaluate reproducibility and effects of treadmill inclination on submaximal and maximal oxygen consumption. They performed a standard Bruce protocol twice, and 1 protocol with progressive speed increase with constant, or without, inclination. At maximal exercise there was no significant difference between the protocols in oxygen consumption, respiratory gas exchange ratio, minute ventilation, plasma lactate, serum potassium or heart rate. Exercise time and treadmill distance were shorter than Bruce protocol with inclination, and considerably prolonged without. Reproducibility for Bruce protocol was good for group comparison of oxygen consumption throughout exercise. The individual variations for oxygen consumption were small at maximal exercise, but were considerable at rest and at the lowest exercise steps, this was slightly improved by analysing longer sampling time. Thus, measurement of oxygen consumption is reliable for group analysis, but interpretation must be careful in individuals unless maximal exercise is obtained. Treadmill inclination may be adjusted according to individual preferences.

Adolescent

The safety of maximal exercise testing.

Previous reports on the safety of exercise testing have been based on surveys from different testing facilities with a variety of testing protocols and patient types. From 1971 through 1987, 71,914 maximal exercise tests conducted in a population with a low prevalence of known coronary heart disease under uniform conditions at a single medical facility resulted in six major cardiac complications including one death. No complications have occurred in the past 10 years in 45,000 maximal tests. The overall cardiac complication rate in men and women is 0.8 complications per 10,000 tests with 95% confidence intervals of 0.3-1.9 complications per 10,000 tests. Maximal exercise testing appears safer than some previously published reports have suggested and seems to be getting safer with time.

Accident Prevention

[Hyperventilation test in coronary disease: a comparison with a bicycle ergometer exercise test. Report of 100 cases].

A hundred cases have been studied and divided into three categories:--60 normal subjects;--30 coronary subjects with a positive exercise test;--10 subjects with defective nervous control of the circulation; using the exercise test, we studied the effects of hyperventilation on repolarisation of the ventricle. In the normal subjects there was no ischaemic depression of the ST segment, but there were minor changes in repolarisation which affected the T wave in 73% of subjects and were essentially posterior in distribution. In the coronary subjects, we found three with ischaemic depression of the ST segment and one with ST elevation of 2.5 mm (6.7% of the coronary subjects). This last finding is evidence against the commonly held hypothesis that reproduction of ST depression by hyperventilation during the exercise test indicates a false positive test. In the patients with defective nervous control of the circulation, 9 had an ischaemic type of ST depression, either as a new feature or as a more severe one compared with that found at rest. The mechanism by which these depressions are produced has not been totally explained:--in the cases with defective nervous control of the circulation, it appears that latent increased sympathetic activity is increased by the hyperventilation;--in the coronary subjects, it may be caused by true ischaemia or by an associated defect in nervous control of the circulation.

Adult

Symptom-limited versus low level exercise testing before hospital discharge after myocardial infarction.

OBJECTIVE: This study was undertaken to compare a low level and a symptom-limited test performed before hospital discharge after an uncomplicated myocardial infarction. BACKGROUND: Exercise testing after myocardial infarction provides useful prognostic information. Usually either a low level test is performed before hospital discharge or a symptom-limited test is performed at 3 weeks. METHODS: The study group comprised 202 patients with an uncomplicated myocardial infarction; 58 patients had a non-Q wave infarction and 115 patients had received thrombolytic therapy. Both a low level and a symptom-limited exercise test were performed in 200 of the 202 study patients in randomized order on consecutive days, a mean of 7.4 +/- 2.3 days after infarction. RESULTS: The symptom-limited test required a considerably greater effort than the low level test: exercise duration was 554 +/- 209 versus 389 +/- 125 s (p less than 0.0001), and peak work load was 5.7 +/- 1.8 versus 4.2 +/- 1.1 METs (p less than 0.0001). The peak heart rate was higher during the symptom-limited test (121 +/- 20 vs. 108 +/- 14 beats/min, p less than 0.0001), as was the rate-pressure product. The number of patients who developed ST segment depression greater than or equal to 1 mm increased from 56 during the low level test to 89 during the symptom-limited test (p less than 0.0001). ST segment depression greater than or equal to 2 mm occurred in 22 patients during the low level test and in 41 patients during the symptom-limited test, an 86% increase (p less than 0.0001). The number of patients with either angina or ST depression greater than or equal to 1 mm increased from 66 to 105 (p less than 0.0001) with the symptom-limited test. Exercise test results were similar for patients with a Q wave or a non-Q wave infarction. Exercise duration was longer and exercise-induced ST depression less frequent in patients who had received thrombolytic therapy. CONCLUSIONS: A symptom-limited exercise test performed before hospital discharge after uncomplicated myocardial infarction provides a significantly greater cardiovascular stress than does a low level test and is associated with an ischemic response nearly twice as frequently. The prognostic significance of a positive response at higher work loads has not been defined.

Angina Pectoris

Autonomic dysfunction and silent myocardial ischaemia on exercise testing in diabetes mellitus.

The incidence and mechanism of painless myocardial ischaemia on exercise testing in diabetic patients is not clear. Therefore, two studies were performed. Retrospectively, all exercise tests carried out in our hospital during the past 5 years were reviewed for silent ischaemia. Prospectively, diabetic patients with known or suspected coronary artery disease underwent autonomic function testing and a second exercise test. Of 1653 exercise tests reviewed, 247 were positive (ST depression greater than 0.1 mV). Of the 29 diabetic patients with positive tests 20 (69%) had painless ST depression, compared with 77 (35%) of the 218 non-diabetic patients (p less than 0.001). The diabetic patients with painful and painless ST depression were comparable for age, sex, therapy, but the 20 with no pain on exercise testing had a longer duration of diabetes and a higher incidence of microvascular complications than the 9 with pain (70 vs 22%, p less than 0.05). In the prospective study, 12 of 30 diabetic patients with positive exercise tests had pain in association with ST depression and 18 had no pain. Six patients had mild and 12 severe autonomic neuropathy on formal testing. Twelve had no autonomic dysfunction. Eleven (92%) of 12 patients with severe neuropathy had painless ST depression, compared with 7 (39%) of 18 without severe neuropathy (p less than 0.01). Thus, silent myocardial ischaemia on exercise testing is common among patients with diabetes mellitus and is associated with severe autonomic dysfunction.

Aged

[Hypertensive reaction to exercise. Retrospective studies of 1363 consecutive exercise tests].

OBJECTIVE: To study exercise hypertensive reaction and its relation with rest blood pressure, hypertension type and hypertensive cardiac disease. DESIGN: Retrospective study of treadmill exercise testes (ET) performed from January/89 to June/91: (n: 1703). SETTING: Stress tests Laboratory of Cardiology Service of a Military Hospital. METHODS: 1363 consecutive ET of male subjects, performing at least the 3rd stage of the Bruce protocol, were studied. From each ET record were obtained general data, including the reason for test, medication and the rest and exercise blood pressure. Exercise hypertensive reaction was defined as a Bruce protocol 3rd stage systolic blood pressure above 187 mmHg, which corresponds to mean +2SD of 130 normal male subjects previously studied. The Echocardiograms of non-treated hypertensives, obtained less than a month from ET, were reviewed. The diagnosis of borderline or moderate hypertension was base on the clinical records. RESULTS: 1) The 1363 ET included 132 (9.7%) ET to study hypertensive subjects, and 68 of these had hypertensive reaction. 86 ET were performed by non-treated hypertensive subjects, of whom 73 had Echocardiogram. 43 (3.5%) from 1231 ET performed by non-hypertensive subjects also had exercise hypertensive reaction. 2) The left ventricular (LV) mass index of non-treated hypertensive patients had a positive correlation with exercise systolic pressure (r: 0.45; p < 0.001), more important than with rest blood pressure or exercise systolic pressure response; there was a relation with LV wall thickness, but not with internal ventricular dimensions, that was only observed in hypertensive subjects that also had hypertensive reaction to exercise. 3) Exercise systolic blood pressure was usually normal in borderline and elevated in moderate hypertensives (Qui2: 27.249; p < 0.001). 4) Subjects with exercise hypertensive reaction, but not previously diagnosed as hypertensives, were usually true hypertensives. CONCLUSIONS: 1) Hypertensive peaks seem to be an important determinant factor in LV hypertrophy of hypertension, but its influence is felt only above a certain blood pressure threshold; it results on LV concentric type hypertrophy. 2) Exercise systolic blood pressure had a discrimination power of about 80% to separate borderline and moderate hypertensive subjects. 3) All subjects having an exercise hypertensive reaction must be carefully observed, even if their blood pressure at rest is normal, because most of them are true hypertensive patients.

Adult

[Effect of beta adrenergic blocking drugs on the prognostic value of ST-segment depression during exercise electrocardiogram testing].

Exercise testing has been shown to be predictive for future cardiac events in patients with established diagnosis of coronary heart disease. Exercise test parameters associated with poor prognosis may be unreliable if patient is receiving beta adrenergic agents. The purpose of this study was: 1) to compare the results of exercise testing performed before and during beta blocking therapy, and 2) to determine the role of beta blockers in the prognostic significance of the ST-segment response recorded during exercise testing. The study population consisted of 518 patients (mean age 52 +/- 7 years) with coronary heart disease. The diagnosis was based on the presence of one of the following three criteria: 1) typical history and significant ST-segment depression on resting or exercise electrocardiogram, 2) history of myocardial infarction, 3) significant coronary angiographic abnormalities. In all patients symptom-limited exercise test was performed before and two weeks after the onset of beta blocker therapy. The data from the first and second tests were estimated for significance of differences between the mean values with following results: maximal heart rate--135 +/- 21 and 123 +/- 19 bpm (p less than 0.001), maximal work load achieved--98 +/- 43 and 109 +/- 44 W (p less than 0.001), maximal systolic blood pressure--171 +/- 28 and 163 +/- 26 mmHg (p less than 0.001). Occurrence of characteristic ST-segment depression was more frequent during the first than during the second test (p less than 0.001).(ABSTRACT TRUNCATED AT 250 WORDS)

Adrenergic beta-Antagonists

"Recovery only" ST-segment depression and the predictive accuracy of the exercise test.

STUDY OBJECTIVE: To clarify the predictive value of exercise-induced ST-segment depression occurring in recovery only, and to determine whether the addition of recovery data improves the interpretation of the exercise test. DESIGN: Retrospective analysis of data collected during exercise testing and coronary angiography. SETTING: A 1000-bed Veterans Affairs Medical Center. PARTICIPANTS: The study included 328 male patients who had had both a sign- or symptom-limited treadmill test and coronary angiography. MEASUREMENTS AND MAIN RESULTS: Of the 168 patients who had abnormal ST-segment responses, 26 had such responses only during recovery. The positive predictive value of this pattern for significant angiographic disease (84%) was not statistically different from the predictive value of ST depression occurring during exercise (87%). Inclusion of ST depression during recovery significantly increased the sensitivity of the exercise test from 50% to 59% (P = 0.01) without a change in predictive value. In addition, ST-segment depression occurring only during exercise is usually associated with less-severe angiographic coronary artery disease. CONCLUSION: The occurrence of ST-segment depression during the recovery period only, does not generally represent a "false-positive" response. The inclusion of findings from this period increases the diagnostic yield of the exercise test. Previously proposed exercise test scores, as well as exercise electrocardiography (ECG) analysis done in conjunction with scintigraphy, have a falsely lowered sensitivity that could be increased by considering ST-segment changes occurring in recovery.

Aged

[Early exercise test after acute myocardial infarction].

PURPOSE: To study the predischarge exercise testing importance in determining prognosis after acute myocardial infarction (AMI). PATIENTS AND METHODS: Treadmill exercise testing was performed in 50 stable and without complications patients with AMI, just before hospital discharge; there were 43 men and 7 women, mean age of 53.6 +/- 9.3 years. It was used the modified Naughton protocol and there were no casualties during the exercise testing. Patients were followed up for a mean period of 22.2 +/- 7.7 months. RESULTS: The test was positive in 32% of the patients, abnormal (inadequate blood pressure, heart rate response or arrhythmia) in 36% and normal in 42%. During the first year of follow-up, eleven patients presented with a serious cardiac event. There was one cardiovascular death, 6 patients with unstable angina, 2 reinfarctions and 7 patients had a coronary bypass revascularization. The cumulative risk for these events at one year after myocardial infarction was 50% in patients with a positive exercise test, and 5% in those with a normal exercise test (p less than 0.005). CONCLUSION: The predischarge exercise testing proved to be a simple and safe method to determine prognosis after acute myocardial infarction, identifying a high risk group early after the acute event.

Adult

The evolving role of exercise testing prior to lung resection.

Exercise testing prior to lung resection has long and honored tradition. It began as a test of tolerance using simple techniques such as stair climbing. This was followed by aggressive and invasive protocols using right cardiac catheterization in the search for pulmonary hypertension. More recently, measurement of VO2 with exercise has been reported to predict both postoperative mortality and survivable morbidity. Exercise testing holds promise as a noninvasive test to predict the physiologic outcome from lung resection. Significant questions remain concerning the pathophysiologic mechanisms responsible for an abnormal result and who should be denied thoracotomy based on these results.

Exercise Test

Effects of training on resting and postexercise ECG in standardbred horses, using a standardized exercise test.

Five healthy, mature, previously trained Standardbred horses were given no exercise (left in a stall) for 4 months, then jogged (slow exercise) for 3 weeks, and placed in a 6-week training period. Cardiac variables were measured at the beginning of training and after 14, 20, 35, and 42 days of training before and at 10, 15, 20, 25, and 30 minutes after a 1.8-km (in 3:12 +/- 2 seconds) standard, submaximal exercise test on a deep 0.53-km track. There was no significant change during the 6-week conditioning period in the following variables at rest or at any of the times observed during recovery from test exercise: heart rate, PQ-interval, QRS-duration, QT-interval, and ratio of electrical systole to diastole. It appeared that measuring heart rate by electrocardiogram at rest and during recovery from execise is not of significance in evaluating the fitness in the previously trained adult horse.

Animals

Significant sex differences in the correlation of electrocardiographic exercise testing and coronary arteriograms.

Two hundred fifty-one patients (195 male and 56 females) referred for evaluation of chest pain were studied by multistage submaximal stress testing and selective coronary arteriography. In men with positive exercise tests the incidence rate of true positive exercise test results--that is, positive tests associated with 75 percent of greater coronary stenosis--was 89 percent in contrast to a 33 percent incidence rate of true positive exercise test results in women. The incidence rate of false positive excercise test results--that is, positive tests associated with no coronary stenosis or less than 50 percent stenosis--was 8 percent in men in contrast to 67 percent in women. Conversely, the incidence rate of false negative exercise test results (that is, negative exercise tests associated with 75 percent or greater coronary stenosis) was higher in men (37 percent) than in women (12 percent). It is concluded that in men a positive multistage stress test is useful in predicting the presence of significant coronary artery disease although a negative stress test cannot be relied upon to rule out the presence of significant disease. In women, a positive exercise test is of little value in predicting the presence of significant coronary artery disease, whereas a negative test is quite useful in ruling out the presence of significant disease. New criteria should be developed for stress testing of women.

Adult

Optimizing the exercise test for pharmacological investigations.

Exercise trials in cardiology are often hindered by inconsistent approaches to exercise testing. These inconsistencies include the choice of exercise protocol, exercise end points, points of analysis, and absence or misuse of gas exchange data. Gas exchange techniques greatly enhance the accuracy with which cardiopulmonary function is assessed by exercise. Commonly used protocols are not always appropriate for all patients or all studies. Both cardiovascular disease and the exercise protocol can have an important impact on the relation between changes in work rate and oxygen uptake. Ramp protocols appear to offer the greatest promise for assessing cardiopulmonary function. Analyzing hemodynamic and gas exchange responses at several points submaximally, in addition to those at peak exercise, can add important information concerning the efficacy of a drug. A great deal of confusion continues to hinder the application of the gas exchange anaerobic threshold, and many of the commonly used testing end points are not reliable.

Anaerobic Threshold