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PubMed1993

Ambulatory ST-recording has no additional value to exercise test for identification of severe coronary lesions after an episode of unstable coronary artery disease in men.

One month after an episode of unstable coronary artery disease, 95 male patients performed coronary angiography, 48 hours ambulatory ST-recording and also an exercise test. ST-depression occurred in 29.5% during the ST-recording and in 44.2% during the exercise test (p < 0.05). In patients with ST-depression at ambulatory monitoring, 79% demonstrated the same finding at the exercise test. A high risk response at the exercise test--defined as either ST-depression in > or = 3 leads, ST-depression in 1-2 leads with a maximal work load below the 60th percentile or a maximal work load below the 30th percentile regardless of the ECG reaction--occurred in 56.8%. Severe coronary lesions--defined as three vessel disease, left main stenosis or proximal left anterior descending artery stenosis as part of two vessel disease--was observed in 46.3%. Patients with a high risk exercise test response and patients with ST-depression during ST-recording had severe coronary lesions in 67% and 64% respectively. However, a high risk exercise test response occurred in 82%, while ST-depression at ambulatory monitoring was observed only in 41% of the patients with severe coronary lesions (p < 0.001). Thus, ambulatory ST-recording one month after an episode of unstable coronary artery disease in men adds no further information to a symptom limited exercise test in order to identify patients with severe coronary lesions.

Adult↗
PubMed1978

"Silent" myocardial ischemia during and after exercise testing in patients with coronary artery disease.

Although many patients with coronary artery disease (CAD) have a positive exercise test without pain, the frequency and significance of this "silent" ischemia is unclear. Therefore, we studied 122 consecutive clinically stable patients with angiographically defined CAD (greater than 75 per cent luminal stenosis) and a positive exercise test. Seventy-eight patients had pain or anginal equivalent during or after a positive exercise test; 44 did not, including 32 (26 per cent) with no symptoms at all. Patients were evaluated as to age, sex, prior myocardial infarction, congestive failure, hypertension, diabetes mellitus, and digoxin or propranolol therapy--in addition to anginal symptoms before, during, or after the exercise itself. Extent of CAD, presence of collaterals, and left ventricular ejection fraction were also determined. All exercise tests were evaluated for evidence of ST-T abnormalities or prior infarction on the control ECG as well as peak heart rate during exercise and post-exercise degree of ST segment depression. There were no significant differences between patients with and without exercise-induced pain in regard to any of the clinical and angiographic features noted above, demonstrating that "silent" myocardial ischemia during or after exercise testing is not uncommon and is not readily attributable to any obvious clinical or catheterization findings. Further studies are necessary to determine if patients with evidence of "silent" myocardial ischemia are especially prone to sudden death.

Angina Pectoris↗
PubMed1992

Respiratory mechanics of horses during stepwise treadmill exercise tests, and the effect of clenbuterol pretreatment on them.

Normal Standardbred horses were given an incremental exercise test on a horizontal treadmill to evaluate the influence of exercise on gas exchange, resistance, dynamic compliance and inertance of the respiratory system. The exercise test consisted of 2 min exercise steps at each of the following speeds: 2.4 m/sec (walk), 4.5 m/sec (slow trot), 7.0 m/sec (fast trot) and 10 m/sec (gallop). At rest and after 1 min of exercise at each step, airflow, tidal volume, respiratory frequency, pharyngeal, mid-oesophageal and transdiaphragmatic pressures and arterial blood gas tensions were measured. The same horses were subsequently treated intravenously with clenbuterol (0.8 microgram/kg) and an identical exercise test and measurement performed 10 min after clenbuterol injection. In response to exercise, there were large increases in tidal volume, respiratory frequency, airflow and pressures. Exercise was associated with a decrease in upper airway resistance but total pulmonary resistance was unchanged. Exercise did not alter inertance or dynamic compliance, horses became hypoxaemic, and at 10 m/sec (galloping) also developed hypercarbia. Treatment with clenbuterol did not alter any of these measurements in response to exercise. These data suggest that dilation of upper airways occurs during exercise, and that inertial forces are important in strenuously exercising horses and may influence the accuracy of dynamic compliance determinations at high exercise intensities.

Airway Resistance↗
PubMed2004

Exercise testing in pediatrics.

This article discusses exercise physiology and its application in the pediatric population. This article discusses exercise physiology and its application in the pediatric population. The authors briefly review the normal physiologic response to exercise. They then discuss populations in which exercise testing is most useful, the indications and contraindications for graded exercise, and the usual parameters that are measured during testing. Finally, the authors review some of the recent data on exercise performance in specific pediatric populations.

Adolescent↗
PubMed2005

Assessment of ventilatory thresholds during graded and maximal exercise test using time varying analysis of respiratory sinus arrhythmia.

OBJECTIVE: To test whether ventilatory thresholds, measured during an exercise test, could be assessed using time varying analysis of respiratory sinus arrhythmia frequency (f(RSA)). METHODS: Fourteen sedentary subjects and 12 endurance athletes performed a graded and maximal exercise test on a cycle ergometer: initial load 75 W (sedentary subjects) and 150 W (athletes), increments 37.5 W/2 min. f(RSA) was extracted from heart period series using an evolutive model. First (T(V1)) and second (T(V2)) ventilatory thresholds were determined from the time course curves of ventilation and ventilatory equivalents for O(2) and CO(2). RESULTS: f(RSA) was accurately extracted from all recordings and positively correlated to respiratory frequency (r = 0.96 (0.03), p<0.01). In 21 of the 26 subjects, two successive non-linear increases were determined in f(RSA), defining the first (T(RSA1)) and second (T(RSA2)) f(RSA) thresholds. When expressed as a function of power, T(RSA1) and T(RSA2) were not significantly different from and closely linked to T(V1) (r = 0.99, p<0.001) and T(V2) (r = 0.99, p<0.001), respectively. In the five remaining subjects, only one non-linear increase was observed close to T(V2). Significant differences (p<0.04) were found between athlete and sedentary groups when T(RSA1) and T(RSA2) were expressed in terms of absolute and relative power and percentage of maximal aerobic power. In the sedentary group, T(RSA1) and T(RSA2) were 150.3 (18.7) W and 198.3 (28.8) W, respectively, whereas in the athlete group T(RSA1) and T(RSA2) were 247.3 (32.8) W and 316.0 (28.8) W, respectively. CONCLUSIONS: Dynamic analysis of f(RSA) provides a useful tool for identifying ventilatory thresholds during graded and maximal exercise test in sedentary subjects and athletes.

Adult↗
PubMed2006

Diagnostic accuracy of serum B-type natriuretic peptide for myocardial ischemia detection during exercise testing with spect perfusion imaging.

OBJECTIVE: To determine whether serum B-type natriuretic peptide measured at rest and peak exercise and DeltaBNP contribute to the predictive value and diagnostic accuracy of exercise test in the diagnosis of myocardial ischemia. BACKGROUND: Ventricular myocytes release BNP in response to increased wall stress that occurs in acute ischemia. During exercise testing, transient myocardial ischemia could also cause acute myocardial stress and changes in circulating BNP. METHODS: BNP was measured before and immediately after exercise testing with radionuclide imaging in 203 consecutive subjects referred for chest pain evaluation. Tested subjects were classified as ischemic and non-ischemic based on exercise results, and no ischemia, mild-moderate, and severe ischemia according to perfusion scan results. A logistic regression model, constructed of an ROC and an AUC (area under the curve), was used. RESULTS: Ischemic ECG changes (> or =1 mm, horizontal S-T shift) were detected in the treadmill exercise test in 127 subjects (62.6%), and 76 (37.4%) had neither ST segment shift nor chest pain. Baseline BNP was higher in the ischemic group compared to the non-ischemic group (p=0.044); peak BNP was also higher in the ischemic group (p=0.025), as was DeltaBNP (p=0.0126). Of these 127 subjects, 106 (52% of all) had abnormal perfusion scan results. In the ischemic group, the median baseline, peak exercise BNP, and DeltaBNP values from baseline to peak were higher than in the non-ischemic group. In the severe ischemic group these variables were approximately three-fold higher than in the mild-moderate ischemic group (p<0.0001 for baseline; p<0.0001 for peak; and p<0.0001 for DeltaBNP). Rest, peak exercise, and DeltaBNP values were significantly higher in patients with previous myocardial infarction (p<0.001) and in patients treated with beta blockers; peak exercise BNP was higher in hypertensives and diabetics (p<0.05). The ROC convergence model showed that the AUC for peak-exercise BNP was best able to discriminate and predict severe ischemia and no ischemia, while DeltaBNP from rest to peak exercise discriminated best between mild-moderate and severe ischemia. CONCLUSIONS: Peak exercise BNP and DeltaBNP improved the sensitivity, specificity, positive likelihood ratio, predictive value, and diagnostic accuracy of severe ischemia detection during an exercise test. The contribution of BNP determination during exercise was, however, less impressive than previously reported by others.

Aged↗
PubMed2001

Sarcoidosis: the value of exercise testing.

STUDY OBJECTIVES: To evaluate exercise testing for the assessment of the extent of pulmonary disease in patients with sarcoidosis. DESIGN: Retrospective analysis of consecutive patients with sarcoidosis referred to the Pulmonary Physiology Laboratory between 1992 and 1997, who completed at least 6 min of progressive bicycle exercise. Resting and exercise pulmonary function measurements were compared to radiographic stage of disease. SETTING: Pulmonary Physiology Laboratory at Washington, DC, Veterans Affairs Medical Center. PATIENTS: Forty-eight outpatient veterans with biopsy specimen-proven sarcoidosis. RESULTS: Across all radiographic stages of sarcoidosis, total lung capacity, resting diffusing capacity, and exercise gas exchange measurements had a significant variance with radiographic stage. Across the early radiographic stage disease (stages 0 to 2), the change in alveolar-arterial oxygen pressure gradient between rest and exercise, normalized for oxygen uptake, was the most significant measurement in its variation with radiographic stage. CONCLUSIONS: Changes in gas exchange with exercise may be the most sensitive physiologic measurements to assess the extent of disease in early radiographic stages of sarcoidosis.

Adult↗
PubMed1983

Exercise testing in patients with aortic and mitral valve disease: current applications.

In recent years, exercise testing has become an increasingly important means of evaluating subtle symptomatic changes in patients with aortic and mitral valve disease. Perhaps more significantly, however, when employed with other objective indicators of cardiac function, exercise testing appears to be of value in identifying patients with clinically important deterioration of myocardial function and in assessing the efficacy of various forms of therapy. As investigation of the role of exercise testing in these patients continues, it seems likely that application of exercise testing will prove of value in the rational selection of patients for available therapy.

Aortic Valve Insufficiency↗
PubMed1983

Prognostic significance of the ST-segment response during exercise test shortly after acute myocardial infarction. Comparison with other exercise variables.

An exercise test was made in 317 patients in the third week after acute myocardial infarction. The following types of exercise associated ST-segment responses were registered in patients less than 70-years-old. I: no ST-deviation (33.6%), II: ST-depression (42.9%), III: ST-elevation (13.4%) and IV: inconclusive ST-response (10.1%). The 5-year mortality was significantly lower in group III than in groups II and IV. Group IV had a significantly higher 5-year mortality than all the other groups. Patients with ST-depression had an increased late mortality compared to that of the patients without ST-deviation, but the total mortality did not differ between these two groups. A highly increased risk of dying was found in groups I, II and IV in patients with exercise associated major ventricular arrhythmias and/or with a small increase of the pressure-rate-product (PRP) during exercise. Patients without arrhythmias and with a high increase of the PRP had a low mortality rate irrespective of their ST-response. In the older patients (70-years-old or more) the ST-response was of no prognostic value at all. The ST-segment response was thus generally of limited value in the prognostic management of the present patients. Their survival was mainly determined by the other exercise variables-the magnitude of an exercise index of left ventricular function and the occurrence of ventricular arrhythmias.

Adult↗
PubMed1986

The role of exercise testing in identifying patients with improved survival after coronary artery bypass surgery.

To determine whether exercise testing can identify patients whose survival might be prolonged by coronary artery bypass surgery, the results of bypass surgery were compared with those of medical therapy alone in 5,303 nonrandomized patients from the Coronary Artery Surgery Study registry who underwent exercise testing. Patients in the two treatment groups differed substantially with regard to important baseline variables. Analysis of 32 variables by Cox's regression model for survival revealed an independent beneficial effect of bypass surgery on survival (p less than 0.00001). Patients were then stratified into subsets according to the results of exercise testing. Surgical benefit was greatest in the 789 patients who exhibited at least 1 mm of ST segment depression and who could exercise only into stage 1 or less. Among the 398 patients with three vessel coronary disease showing these characteristics, 7 year survival was 58% for the medical group and 81% for the surgical group (p less than 0.001). There was no difference in survival between the surgical and medical groups among the 1,545 patients without ischemic ST segment depression who were able to exercise into stage 3 or greater. Thus, in patients who demonstrate ischemia on exercise testing and whose exercise capacity is limited, coronary bypass surgery appears to improve survival in comparison with medical therapy alone.

Coronary Artery Bypass↗
PubMed1995

Exercise testing as a long-term predictor of the development of microalbuminuria in normoalbuminuric IDDM patients.

OBJECTIVE: To determine the association between exercise-induced albuminuria and the development of microalbuminuria over 10 years in subjects with insulin-dependent diabetes mellitus (IDDM) who were initially normoalbuminuric. RESEARCH DESIGN AND METHODS: Thirty-two patients with IDDM and a resting urinary albumin/creatinine ratio (UA/UC) < 2.1 mg/mmol (< 15 micrograms/min) were exercised after water loading on a treadmill for 20 min at double their resting heart rate. UA/UC was determined before and after exercise. The exercise test was considered positive if the UA/UC was > 4.3 mg/mmol (> 30 micrograms/min). Results were compared with resting UA/UC after a 10-year follow-up. Persistent microalbuminuria was defined as a UA/UC > 2.1 mg/mmol (> 15 micrograms/min) in each of two early-morning urine collections. RESULTS: Five patients developed persistent microalbuminuria after 10 years, and four patients were predicted by a positive exercise test. Two patients with positive exercise tests did not develop persistent microalbuminuria. The sensitivity of the exercise test for the development of microalbuminuria was 80% (95% confidence interval [CI] 65.8-94.2%) and the specificity was 92.9% (95% CI 83.9-100%). The postexercise UA/UC was positively associated with the UA/UC after 10 years (P = 0.005, R2 = 0.31). This association was independent of HbA1, systolic blood pressure, body mass index, and duration of diabetes, but HbA1 remained an independent predictor (P = 0.02) of UA/UC at follow-up. CONCLUSIONS: Exercise testing may be useful for identifying normoalbuminuric IDDM patients who are susceptible to the later development of microalbuminuria.

Adult↗
PubMed2005

Can we reliably predict long-term mortality after exercise testing? An external validation.

OBJECTIVE: The aim of the study was to derive and externally validate a mortality prediction rule for patients undergoing exercise testing. BACKGROUND: The prognostic value of exercise testing is increasingly appreciated. However, global prognosis estimates ideally should account for numerous routinely obtained variables, including demographics, risk factors, resting electrocardiogram, and multiple exercise test measures. METHODS: A prediction rule was derived by parametric hazards modeling on a derivation set of 46047 Cleveland Clinic patients (age 55 +/- 11 years, 67% male) who had no history of heart failure, valve disease, or atrial fibrillation. Twenty-two variables covering demographics, risk factors, exercise hemodynamics, and electrocardiogram findings at rest and during exercise were considered. The resulting model included 16 variables and was tested on 4981 patients (age 50 +/- 12 years, 55% male) who underwent exercise testing at West Virginia University. RESULTS: In the derivation cohort there were 3173 deaths during a mean of 7 years of follow-up, whereas in the validation cohort there were 180 deaths during a mean of 5 years of follow-up. Comparisons of predicted and observed death rates showed very good agreement among all patients across all spectrums of risk, as well as among prespecified high-risk subgroups. Model discrimination was also good, with c statistic of c = 0.79 in the derivation group and c = 0.81 in the validation cohort. CONCLUSIONS: We have externally validated a mortality prediction rule for patients undergoing exercise testing and confirmed its accuracy among a wide spectrum of patients.

Adult↗
PubMed1999

Artifact processing during exercise testing.

In signal processing of exercise electrocardiograms (ECGs), artifacts are a recurring problem. It is still difficult to discriminate the ECG curves from artifacts, especially in exercise ECGs and particularly in the high exercise phase. We focused on the artifact problem and worked on two new topics: the Finite Impulse Response Residual Filtering (FRF) algorithm and the Intelligent Lead Switch algorithm. The FRF algorithm reduces the baseline wander and muscle noise in the ECG stream, with much less distortion of the QRS complexes. It subtracts a continuously updated median beat from the current ECG, filters the residual signal with a high-pass and a low-pass filter, and adds the median beat to the filtered residual signal. The Intelligent Lead Switch algorithm takes advantage of the redundancy of a multilead system (eg, standard leads), which is nowadays used during exercise testing. It selects the best leads for QRS detection and thus improves the heart rate calculation, ST segment evaluation, and arrhythmia classification.

Algorithms↗
PubMed2005

Exercise testing in asymptomatic adults: a statement for professionals from the American Heart Association Council on Clinical Cardiology, Subcommittee on Exercise, Cardiac Rehabilitation, and Prevention.

Along with coronary artery calcium scanning, ankle-brachial index measurement, and carotid artery ultrasound, exercise electrocardiography has been proposed as a screening tool for asymptomatic subjects thought to be at intermediate risk for developing clinical coronary disease. A wealth of data indicate that exercise testing can be used to assess and refine prognosis, particularly when emphasis is placed on nonelectrocardiographic measures such as exercise capacity, chronotropic response, heart rate recovery, and ventricular ectopy. Nevertheless, randomized trial data on the clinical value of screening exercise testing are absent; that is, it is not known whether a strategy of routine screening exercise testing in selected subjects reduces the risk for premature mortality or major cardiac morbidity. The writing group believes that a large-scale randomized trial of such a strategy should be performed.

Adult↗
PubMed1999

Can reactive hyperemia be used instead of exercise test in assessment of mild intermittent claudication.

BACKGROUND AND AIMS: Purpose of the study was to find out if reactive hyperemia stress test could serve as an alternative for treadmill exercise test in assessment of mild intermittent claudication (IC). MATERIAL AND METHODS: A total of 22 claudicants with resting ankle brachial index (ABI) ranging from 0.61 to 1.23 were stressed with progressive treadmill exercise test and suprasystolic thigh occlusion test to provoke reactive hyperemia. Immediate pressure measurements were obtained after the test. RESULTS: ABI drop after progressive exercise test was in average 0.29 and after reactive hyperemia 0.16. The pressures indices after these stress tests correlated well (r = 0.82). The tests were equally good in detecting mild arteriosclerotic disease. CONCLUSIONS: In conclusion, although postexercise ABI was able to detect mild atherosclerotic disease as the reason for IC with a better marginal than hyperemia test both methods are useful. In circumstances where the patient is for some reason unable to carry out treadmill test reactive hyperemia test is an alternative for differential diagnosis. This enables vascular surgeons to improve their diagnostics without vascular laboratory.

Arteriosclerosis↗
PubMed1989

Prognostic value of an exercise test one year after myocardial infarction.

An exercise test was performed in 306 patients who had had acute myocardial infarction one year previously. The five year cumulative coronary heart disease mortality was 40.0%, when the test had to be discontinued because of ventricular arrhythmias but only 13.0% if discontinued because of fatigue (P less than 0.05). If the maximum work load was less than 80 W the mortality was 30.7% compared with 16.6% in patients who exercised at least 80 W (P less than 0.01). If maximum systolic blood pressure was less than or equal to 150 mmHg mortality was 40.3% compared with 8.5% in patients with greater than 200 mgHg (P less than 0.001). The mortality was 38.2% in patients having single monoform ventricular ectopic beats at a rate of three or more per minute or multiform, paired or early cycle ventricular ectopic beats or ventricular tachycardias: this compared with 14.1% (P less than 0.001) in patients having no or only single monoform ventricular ectopic beats at a rate of less than three per minute. ST-segment depression in univariate testing had no prognostic value. When both exercise test and clinical variables were used in survival analysis (Cox's regression) the most important variable was heart volume and after that ventricular arrhythmias. In multivariate regression analysis ST segment depression also had additional prognostic value. Thus ventricular arrhythmias turned out to be the most important prognostic factor measured during exercise test.

Aged↗
PubMedDate not supplied

Cardiorespiratory function as assessed by exercise testing in patients with non-insulin-dependent diabetes mellitus.

Exercise testing was used to examine 19 cardiorespiratory diabetes mellitus patients, aged 32-68 years (body mass index, 27.8 +/- 4.8 kg/m2), and 16 healthy volunteers, aged 23-57 years (body mass index, 22.7 +/- kg/m2). A graded cycling exercise test was done, monitoring gas exchange, ventilation and heart rate. Values were significantly higher in the non-insulin-dependent diabetes mellitus (NIDDM) patients than in the controls for fasting blood glucose (P < 0.01), glycosylated haemoglobin (P < 0.01), body weight (P < 0.05) and body mass index (P < 0.05). The exercise testing produced values that were significantly lower in the patients with NIDDM than in the controls for percentage oxygen uptake (P < 0.05), maximum load (P < 0.05), maximum metabolic equivalent (P < 0.01) and maximum oxygen uptake per unit body weight (P < 0.01). Ventilatory capacity and forced expiratory volume at 1 sec did not differ significantly in the two groups. These results suggest that general fitness is diminished due to reduced cardiorespiratory function in patients with NIDDM.

Adult↗
PubMed2006

[Exercise test in athletes].

The particularities of exercise tests in athletes concern mainly the exertion protocols adapted to their increased physical capacities and the interpretation of ECG tracing which can sometimes be very special at rest and also misleading during exercise. In the great majority of cases, the test used is both cardiac and pulmonary, in order to assess the aerobic capacities, the maximal aerobic power, and the determination of ventilation thresholds (programming and follow-up of training...). More infrequently, the test is used to detect cardiovascular diseases, especially during a longitudinal follow-up of high-level athletes, or to exclude it in case of cardiovascular symptoms, atypical resting ECG or even in case of suspicion of disease (arrhythmia, cardiac chamber hypertrophy or dilation at echocardiography). In more aged sportsmen (athletes masters), exercise tests performed are usually required for screening coronary heart disease. In this case the test protocols should be more adapted for screening than for the assessment of sportive capacities.

Electrocardiography↗