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Treadmill exercise test in aortic stenosis and mitral stenosis.

The incidence of positive submaximal treadmill exercise tests was evaluated in patients with mitral stenosis and aortic stenosis, no electrocardiographic evidence of left ventricular hypertrophy, and normal coronary arteries on angiography. Seven of 19 patients (37 percent) with aortic stenosis (53 to 80 mm Hg gradient across the aortic valve) had greater than or equal to 1.0 mm of ischemic S-T segment depression during or after a submaximal treadmill test. Three of 15 patients (20 percent) with mitral stenosis (11 to 22 mm Hg mean gradient across the mitral valve) had greater than or equal to 1.0 mm of ischemic S-T segment depression during or after a submaximal treadmill exercise test. Patients with significant valvular disease, no electrocardiographic evidence of left ventricular hypertrophy, and normal coronary arteries may have a positive submaximal treadmill exercise test due to an unfavorable balance between myocardial oxygen supply and myocardial oxygen demand.

Adult↗

[Exercise test after acute myocardial infarction: without therapy?].

In this article we analyze the role of ECG exercise test in the clinical evaluation and prognostic stratification of patients after acute myocardial infarction. Moreover, we analyze if test results may be influenced by drugs. In clinical practice, most of the cardiologists working in hospital perform pre-discharge tests while patients are on medical therapy; after the acute event, exercise test is performed after pharmacological wash-out. In the thrombolytic age exercise test has a well-defined role in the evaluation and prognostic stratification of postinfarction patients, but some aspects regarding the way of performance and the opportunity of a pharmacological wash-out need further investigation.

Data Interpretation, Statistical↗

Estimating the total energy demand for supra-maximal exercise using the VO2-power regression from an incremental exercise test.

The VO2-power regression and estimated total energy demand for a 6-minute supra-maximal exercise test was predicted from a continuous incremental exercise test. Sub-maximal VO2-power co-ordinates were established from the last 40 seconds (s) of 150-second exercise stages. The precision of the estimated total energy demand was determined using the 95% confidence interval (95% CI) of the estimated total energy demand. The linearity of the individual VO2-power regression equations was determined using Pearson's correlation coefficient. The mean 95% CI of the estimated total energy demand was 5.9 +/- 2.5 mL O2 Eq x kg(-1) x min(-1), and the mean correlation coefficient was 0.9942 +/- 0.0042. The current study contends that the sub-maximal VO2-power co-ordinates from a continuous incremental exercise test can be used to estimate supra-maximal energy demand without compromising the precision of the accumulated oxygen deficit (AOD) method.

Adult↗

Reproducibility of the catecholamine response to serial exercise testing in normals.

Plasma norepinephrine (NE) and epinephrine (E) increase with exercise but the reproducibility of their response to short-term serial exercise testing has not been established. Therefore, NE and E were measured at rest, 6 minutes, peak exercise, and 5 minutes postexercise in 10 normal subjects undergoing three identical exercise tolerance tests within 4-13 days. Norepinephrine and E were also measured in tests 2 and 3 at the time equivalent to the peak exercise duration in test 1 (peak--equivalent). Exercise duration increased slightly from test 1 (15.6 +/- 0.7 min) to test 2 (16.5 +/- 0.5 min; p = 0.07) but no further on test 3 (16.2 +/- 0.9 min). Norepinephrine and E did not differ across the three tests at rest, 6 minutes, peak test or posttest, but a significant decrease in both NE and E was seen at peak-equivalent by test 3 (p less than 0.05). Heart rate decreased across the three tests at 3, 6, 9, and 12 minutes (p less than 0.02 for each) and peak equivalent (p less than 0.005) but was unchanged at rest, peak exercise and postexercise. Thus, plasma catecholamines and heart rate decrease at high levels of exercise with repeated, short-term exercise testing, possibly due to familiarity with the protocol. These results suggest that control groups are important when measuring the effects of short-term pharmacologic intervention by serial exercise tests.

Adult↗

[Exercise test and differential diagnosis of fetal arrhythmia].

The cases here reported show in the first place that external fetal ECG is useful to detect fetal distress and should therefore be included as a prenatal control from the second trimester of pregnancy on, specially in cases where there is a past history of fetal death of unknown origin, or a family history of congenital heart defects. A fetal tolerance test to exercise should also be done in those cases with a past history of fetal death, distress or whenever chronic fetal distress may be suspected to take place because of the presence of maternal pathology (endocrine, cardiovascular, or infectious diseases, etc.). Fetal tolerance test to uterine contractions should also be done whenever possible to evaluate the tolerance of these fetuses to uterine contractility during labor. More studies are needed to establish standard guides of this method for the practical obstetrical management of products of high risk pregnancies.

Adult↗

Graded exercise testing for spaceflight.

We developed and validated a graded exercise protocol suitable for operational use on space station. The new treadmill protocol has three level-grade stages (3-min each) at 70, 80, and 90% of estimated VO2peak. The protocol maintains the third stage speed while grade increases each minute to produce work rates equivalent to 100, 107, and 115% of the estimated VO2peak. We compared the new protocol's peak and submaximal responses to those observed during a NASA graded exercise test. All mean protocol differences, including peak work rate (-1.8%), VO2peak (-6.4%), HRpeak (-2.4%), and VEpeak (-9.7%), were not significantly different from the expected measurement errors. We observed similar results for indices (the oxygen uptake at a HR of 150 and the HR's at 70, 80, and 90% of VO2peak) of the submaximal HR-VO2 relationship. The new protocol is an acceptable graded exercise test for periodic operational fitness tests.

Adult↗

Risk stratification by early exercise testing after an episode of unstable coronary artery disease. The RISC Study Group.

After stabilization of symptoms by medication a predischarge exercise test was performed in 855 men admitted with suspected unstable angina (54%) or non-Q-wave myocardial infarction (46%). Multiple logistic regression analysis demonstrated that the number of leads with ST-depression at exercise, low maximal work load, increasing age and ST-elevation in electrocardiogram at rest had independent prognostic value concerning the risk of myocardial infarction or death during the following year. Therefore a combination of extension of ST-depression and peak work load was used to define 'high and low risk response' at the exercise test. After 1 year the mortality in patients with 'high risk' compared to 'low risk' exercise response was 3.6% and 0% (P < 0.001) and the risk of either myocardial infarction or death was 15.4% and 3.9% (P < 0.0001), respectively. ST-depression, occurrence of angina and low peak load at exercise were independent predictors of future severe angina. After 1 year 29.5% of patients with any of these indicators at exercise had incapacitating symptoms that necessitated referral for coronary angiography compared to 4.8% in the group without these findings (P < 0.0001). The predictive value of the exercise test remained high in subgroups based on inclusion diagnosis, age or findings in electrocardiogram at rest and independently of treatment with beta-blockade, other antianginal medication or aspirin at the time of the exercise test.

Aged↗

Relationship between ventilatory expired gas and cardiac parameters during symptom-limited exercise testing in patients with heart failure.

PURPOSE: This study investigates the relationship between ventilatory expired gas and cardiac parameters measured during exercise testing in patients with heart failure. METHODS: Twenty-five subjects (12 male, 13 female) diagnosed with compensated heart failure underwent symptom-limited exercise testing with ventilatory expired gas analysis. Metabolic and cardiac measures of interest were collected during testing. RESULTS: Mean peak oxygen consumption (VO2), minute ventilation/carbon dioxide production (VE/VCO2) slope, percentage of age predicted maximal heart rate achieved during exercise testing (%APMHR), and peak respiratory exchange ratio were 14.7 +/- 4.7 mL O2/kg/min-1, 33.8 +/- 9.8, 76% +/- 15%, and 1.1 +/- 0.11, respectively. The VE/VCO2 slope was significantly correlated with the following: %APMHR (r = -0.81, P < 0.001), peak VO2 (r = -0.83, P < 0.001), VO2 at ventilatory threshold (r = -0.70, P < 0.001), and the dead space to tidal volume ratio (VD/Vt) (r = 0.65, P < 0.001). The ability of peak VO2 and %APMHR to predict the VE/VCO2 slope was significant (r = 0.86, r2 = 0.72, P < 0.0001). CONCLUSION: This study demonstrates the importance of analyzing multiple exercise test parameters, including metabolic measures, in patients with heart failure.

Adult↗

Exercise testing and prognosis in adult cystic fibrosis.

BACKGROUND: The assessment of prognosis is an important issue in cystic fibrosis. The prognostic value of exercise testing in comparison with other predictors of mortality was examined. METHODS: Ninety two adult patients with cystic fibrosis performed progressive maximal exercise tests and outcome was assessed at five years. The results of exercise testing were examined along with spirometric values, age, sex, body mass index (BMI), and sputum culture. RESULTS: Twenty two subjects died during the five year follow up period and 67 survived. Five subjects received a lung transplant and were excluded from the analysis. There were significant differences between those who survived and those who died: mean (SE) forced expiratory volume in one second (FEV1) 68.9 (2.7) versus 39.7 (3.5)% predicted, BMI 19.0 (0.3) versus 17.1 (0.4) kg/m2, peak oxygen uptake (VO2 peak) 66.6 (2.2) versus (53.7) (3.7)% predicted, peak work rate (Wpeak) 89.4 (3.8) versus 71.2 (5.5)% predicted, peak minute ventilation (VEpeak) 51.3 (2.0) versus 43.3 (3.1) 1/min, and ventilatory equivalent for oxygen (VE/VO2) 32.4 (0.6) versus 38.7 (1.7). Age, sex, oxygen saturation and Burkholderia cepacia colonisation were not found to be significant predictors of mortality. When significant independent factors were entered into a multivariate logistic regression model only FEV1 was found to be a significant correlate of mortality. A cutoff for FEV1 of 55% predicted gave the best combination of specificity and sensitivity with 54% of those below this value dying within five years and 96% of those above it surviving. CONCLUSIONS: The results of maximal exercise testing are correlated with survival but they are not better than the FEV1 as prognostic indicators.

Adolescent↗

Feasibility of maximal cardiopulmonary exercise testing in patients with end-stage arthritis of the hip and knee prior to total joint arthroplasty.

STUDY OBJECTIVE: Although no studies exist, to our knowledge, that examine the feasibility and safety of stress testing in a consecutive series of patients with severe arthritis, musculoskeletal conditions are often listed as relative contraindications to graded exercise testing. The current study was designed to examine the feasibility of maximal exercise testing in patients with end-stage arthritis prior to total joint arthroplasty. DESIGN: An observational and descriptive study in a consecutive series of patients with severe arthritis. SETTING: This study was conducted in the outpatient clinics and cardiopulmonary exercise physiology laboratory of a rural teaching hospital. PARTICIPANTS: Sixty-one patients with severe osteoarthritis and rheumatoid arthritis were recruited from the orthopedic surgical service immediately before total joint arthroplasty of the hip, knee, or both. A reference group of 23 nonarthritic control patients were recruited from the general medical population of the same hospital and subjected to measures of arthritis severity. MEASUREMENTS AND RESULTS: The severity of arthritis was graded by assessment of variables reflective of subjective symptoms, lifestyle impact, joint deformity, and radiographic abnormality. Arthritic subjects underwent a single graded, maximal, symptom-limited, cardiopulmonary exercise test using an electronically braked ergometer and a metabolic cart. Subjects were first asked to pedal with their legs; those apparently incapable performed the same task using their arms. Ninety-five percent of subjects who presented for an exercise test were capable of symptom-limited exercise. Of 29 patients evaluated before hip replacement, 66% completed leg tests, 31% completed arm tests, and 3% were incapable of symptom-limited exercise. Of 30 patients evaluated before knee replacement, 57% completed leg tests and 37% completed arm tests, while 7% were incapable of symptom-limited exercise. Two patients were evaluated before hip and knee surgery; one completed a leg study and one completed an arm study. Among the 37 subjects completing leg tests, a mean percentage of age-predicted maximum heart rate (APMHR) of 92 +/- 11% and a mean respiratory exchange ratio (RER) of 1.15 +/- 0.13 were noted. Among the 21 completing arm tests, a mean percentage of APMHR of 87 +/- 11% and a mean RER of 1.10 +/- 0.10 were observed. High rates of achievement of physiologic values indicative of maximal exercise (80% or more of APMHR and RER > or = 1.0) were noted in individuals in both exercise groups. Similar findings were noted regardless of the patient's subjective symptomatic limitation to exercise and the presence or absence of documented or suspected coronary heart disease. CONCLUSIONS: Most patients with severe arthritis are capable of maximal, symptom-limited exercise using ergometry methods. Ergometry stress testing may be a viable, low-cost alternative to dipyramidole-thallium testing or cardiac catheterization in some patients with arthritis warranting objective assessment of known or suspected cardiac disease.

Aged↗

[Value of exercise test for assessment of hemodynamic efficiency of the heart].

The purpose of the work was an attempt at determination of the value of exercise test for the assessment of haemodynamic heart effectiveness. The reaction of blood pressure and heart rate to exercise was accepted as the basis for analysis. The analysis was based on a material of 40 men aged 33-66 years (mean = 51 years) with a history of myocardial infarction in whom exercise tests were carried out one year after aortocoronary bypass graft implantation. The studied men were divided into two groups A abd B depending on the reaction of blood pressure and heart rate occurring during exercise. Group A consisted of persons who responded to exercise with blood pressure and heart rate in a physiological way. The patients in group B terminated the exercise test due to pathological response. The subject of the analysis were: ischaemic changes during exercise; duration of the exercise test; attained workload in Watts; heart rhythm disturbances in group A and B; segmental left ventricular contractility disturbances evaluated on the basis of echocardiography findings. Among the patients in group B a higher percent of positive tests was found as well as shorter duration of the test and lower mean workload in relation to the patients in group A. Contractility disturbances occurred significantly more frequently - 80% among the patients in group B with greater prevalence of more sever forms of akinesis and dyskinesis (p < 0.05). Hypokinesis was observed in 7 patients (35%), akinesis in 5 cases (25%), and dyskinesis in 4 cases (20%).(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗

Clinical and exercise test predictors of all-cause mortality: results from > 6,000 consecutive referred male patients.

OBJECTIVE: To report the prevalence of abnormal treadmill test responses and their association with mortality in a large consecutive series of patients referred for standard exercise tests, with testing performed and reported in a standardized fashion. BACKGROUND: Exercise testing is widely performed, but few databases exist of large numbers of consecutive tests performed on patients referred for routine clinical purposes using standardized methods. Even fewer of the available databases have information regarding all-cause mortality as an outcome. METHODS: All patients referred for evaluation at two university-affiliated Veterans Affairs medical centers who underwent exercise treadmill testing for clinical indications between 1987 and 2000 were determined to be dead or alive using the Social Security death index after a mean 6.2 years (median, 7 years) of follow-up. Clinical and exercise test variables were collected prospectively according to standard definitions; testing and data management were performed in a standardized fashion using a computer-assisted protocol. All-cause mortality was utilized as the end point for follow-up. Standard survival analysis was performed, including Kaplan-Meier curves and a Cox hazard model. RESULTS: There were 6,213 male patients (mean +/- SD age, 59 +/- 11 years) who underwent standard exercise ECG treadmill testing over the study period with a mean follow-up duration of 6.2 +/- 3.7 years. There were no complications of testing in this clinically referred population, 78% of whom were referred for chest pain, or risk factors or signs or symptoms of ischemic heart disease. Overlapping thirds had typical angina or history of myocardial infarction (MI). Five hundred seventy-nine patients had prior coronary artery bypass surgery, and 522 patients had a history of congestive heart failure (CHF). Indications for testing were in accordance with published guidelines. Twenty percent died over the follow-up period, for an average annual mortality rate of 2.6%. Cox hazard function chose the following variables in rank order as independently and significantly associated with time to death: exercise capacity (metabolic equivalents < 5, age > 65 years, history of CHF, and history of MI. A score based on these variables (summing up the four variables [if yes = 1 point]) classified patients into low-risk, medium-risk, and high-risk groups. The high-risk group (score > or = 3) has a hazard ratio of 5.0 (95% confidence interval, 4.7 to 5.3) and a 5-year mortality rate of 31%. CONCLUSION: This comprehensive analysis provides rates of various abnormal responses that can be expected in patients referred for exercise testing at a typical medical center. Four simple variables combined as a score powerfully stratified patients according to prognosis.

Aged↗

Use of exercise testing in noncoronary heart disease.

Although the application of exercise testing has not been as extensive in patients with noncoronary heart disease as in those with atherosclerotic coronary heart disease, the body of knowledge of the roles of exercise testing in these disorders is increasing. The usefulness of this extension of the clinical examination in the evaluation of patients with a variety of noncoronary cardiovascular disorders is becoming increasingly apparent.

Aortic Coarctation↗

Predicting complications after pulmonary resection. Preoperative exercise testing vs a multifactorial cardiopulmonary risk index.

Recent studies have used preoperative cardiopulmonary exercise testing to improve risk assessment of pulmonary resection for lung cancer. These studies have demonstrated inconsistent correlation between peak oxygen uptake (VO2) and postoperative complications but have not systematically examined other methods of risk stratification. We analyzed the findings in 42 patients who had cardiopulmonary exercise testing prior to lung cancer resection. Preoperative clinical data combining pulmonary factors (obesity, productive cough, wheezing, tobacco use, ratio of the forced expiratory volume in 1 s over the forced vital capacity [FEV1/FVC] < 70 percent, and PaCO2 > 45 mm Hg), and an established cardiac risk index were used to generate a cardiopulmonary risk index (CPRI). When analyzed using the risk index, the incidence of postoperative complications increased with higher CPRI scores. Those with a CPRI of 4 or greater were 22 times more likely to develop a complication, compared to a CPRI of less than 4 (p < 0.0001). We found that patients with a peak VO2 less than 500 ml/m2/min (body surface area) were 6 times more likely to experience a cardiopulmonary complication (p < 0.05). With multiple logistic regression analysis, peak VO2 was not an independent predictor of postoperative complications. Analysis also demonstrated that a CPRI of 4 or greater was associated with significant reductions in peak VO2. We conclude that both the peak VO2 during cardiopulmonary exercise testing and a multifactorial CPRI are highly predictive of complications after lung resection. Adding the peak VO2 did not enhance the risk estimation generated by the CPRI. The association between postoperative complications and peak VO2 may be explained by the correlation between identifiable cardiopulmonary disease (CPRI) and reduced oxygen uptake with exercise.

Electrocardiography↗

Radionuclide imaging correlatives of heart rate impairment during maximal exercise testing.

A lower than normal heart rate response to maximal dynamic exercise, known as chronotropic incompetence or heart rate impairment, has been demonstrated to have a poor prognosis. In order to better describe patients with this finding, 156 men with coronary heart disease were evaluated. All patients were studied with maximal exercise testing, including measurements of oxygen consumption, exercise electrocardiograms, thallium scintigraphy and radionuclide ventriculography. Chronotropic incompetence was defined as a maximal heart rate 1 standard error of the estimate below the regression line of age versus maximal heart rate on two separate exercise tests. In patients so defined, mean maximal oxygen consumption was significantly lowered and angina was the major reason for stopping exercise on the treadmill. Patients with chronotropic incompetence not limited by angina had more evidence of myocardial scar and dysfunction and had a greater prevalence of three vessel coronary disease than did patients with a normal heart rate response. Radionuclide testing results suggest that among patients with chronotropic incompetence, those with angina have a better prognosis than those who do not have angina but who may have myocardial dysfunction.

Adult↗

Influence of R wave analysis upon diagnostic accuracy of exercise testing in women.

Exercise electrocardiography in women with chest pain is associated with a high incidence of false positive ST segment depression. The recent observation that changes in R wave amplitude during exercise can also be used diagnostically may improve the value of stress testing in women. The results of 12 lead treadmill exercise and coronary angiography were reviewed in 62 women, mean age 51 years, presenting with "angina" without previous myocardial infarction. These were compared with exercise results in 14 healthy asymptomatic volunteers with a mean age of 26 years. In addition to conventional ST analysis, R wave amplitude changes during exercise, measured in leads II, III, a VF, and V4 to 6, were examined. While the sensitivity and specificity of ST and R wave changes were similar at about 67%, their combined interpretation was helpful. If both ST and R wave criteria were negative the predictive accuracy for normal coronary angiography was 94% (17/18). Alternatively, in tests showing both ST depression and an abnormal R wave response, coronary angiography was always abnormal (13/13). None of the normal volunteers developed ST segment depression and 93% (13/14) had a normal R wave response. If both were positive, however, coronary angiography was always abnormal (13/13). Although stress test interpretation in women is difficult, R wave analysis is a useful adjunct to ST change and can improve the predictive accuracy of the test in a significant number of patients.

Adult↗

Comparative predictive value of ST-segment depression or angina during early and repeat postinfarction exercise tests.

To determine the relative value of electrocardiographic (ECG) ST-segment depression alone compared to angina alone for predicting multivessel coronary artery disease during early and repeat postinfarction exercise tests, we evaluated 93 postmyocardial infarction patients with modified treadmill exercise tests prior to hospital discharge (mean 14 +/- 2 days), and 36 of these 93 patients with repeat exercise tests at six weeks following infarction. It was concluded that angina alone or angina irrespective of the presence of ST-segment depression are better predictors of multivessel coronary artery disease than ECG ST-segment depression alone, and the persistence of ischemic abnormalities during repeat treadmill exercise tests following infarction is useful for confirming the presence of multivessel coronary artery disease.

Adult↗

Statistical methods to improve the precision of the treadmill exercise test.

OBJECTIVES: The study systematically compared different measures of ST segment depression from the treadmill exercise test. BACKGROUND: The value of the treadmill exercise test for objectively measuring treatment effects is limited by random error in the measurement of ST depression and may be biased by regression to the mean or by the decision to terminate the test. METHODS: Treadmill exercise was performed in 21 subjects with ischemic heart disease 1 h after isosorbide dinitrate 10 mg or placebo in a double-blind randomized crossover study. A 12-lead electrocardiogram (ECG) was recorded every 30 s during and at peak exercise. The relative sample size needed to detect the nitrate effect was compared for different summary measures of ST depression. RESULTS: The ST depression measured from a single unmatched lead at longest equivalent sub-maximal exercise needed the lowest sample size to detect the nitrate effect in paired comparisons (p = 0.000006). Averaging over multiple leads or times did not improve detection of the nitrate effect. The rate of increase in ST depression (in mm/min) calculated by linear regression needed a similar sample size (x1.32, 95% CI 0.62 to 2.58). A larger sample size was needed for ST depression at peak exercise (x2.9, CI 1.3, 11.1) and exercise duration (x4.5, CI 1.5, 38). Time to 1-mm ST depression was the least efficient measurement (relative sample size x15.5, CI 1.6, >1,000). Comparison of matched leads resulted in >2-fold differences in estimates of the nitrate effect because of bias from regression to the mean. CONCLUSIONS: Maximal ST depression at longest equivalent sub-maximal exercise and the maximal rate of increase in ST depression had less bias and random variation than did other commonly used measures. The rate of increase in ST depression is preferred because it can be calculated in either paired or unpaired studies.

Administration, Oral↗