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The effects of frequency of encouragement on performance during maximal exercise testing.

The aim of this study was to determine the effects of frequency of verbal encouragement during maximal exercise testing. Twenty-eight participants (12 males, 16 females) aged 20.9 +/- 1.5 years (mean +/- s) performed a maximal exercise test (VO2max) on a treadmill without any verbal encouragement. The participants were matched according to their pre-test VO2max and placed into either a control group or one of three experimental groups. They performed a second exercise test (post-test) 1 week later. During the second test, the control group received no verbal encouragement; the 20 s (20E), 60 s (60E) and 180 s (180E) encouragement groups received verbal encouragement every 20, 60 and 180 s, respectively, beginning with stage 3 of the exercise test. Relative VO2max, exercise time, blood lactate concentration, respiratory exchange ratio (RER) and ratings of perceived exertion (RPE) were not significantly different from the first test to the second test for the control group without verbal encouragement and the 180E group that received infrequent encouragement. Post-test values were significantly higher than pre-test values for the 20E and 60E groups. The post-test values of the 20E group were significantly higher than their pre-test values for relative VO2max (P < 0.001), exercise time (P < 0.0001), blood lactate concentration (P < 0.05), RER (P < 0.01) and RPE (P < 0.0001); this was also the case for the 60E group for relative VO2max (P < 0.01), blood lactate concentration (P < 0.05), RER (P < 0.05) and RPE (P < 0.05). The results suggest that frequent verbal encouragement (every 20 s and 60 s in the present study) leads to significantly greater maximum effort in a treadmill test than when no encouragement is given or when the encouragement is infrequent (i.e. every 180 s).

Achievement↗

Prognostic ability of VE/VCO2 slope calculations using different exercise test time intervals in subjects with heart failure.

BACKGROUND: The minute ventilation-carbon dioxide production (VE/VCO2) slope, obtained during exercise testing, possesses prognostic value in heart failure (HF). The VE-VCO2 relationship is generally linear thereby hypothetically producing similar slope values regardless of the exercise-test time interval used for calculation. DESIGN: This study assesses the ability of the VE/VCO2 slope, calculated at different time intervals throughout a progressive exercise test, to predict 1-year cardiac-related hospitalization and mortality in subjects with HF. METHODS: Seventy-two subjects underwent symptom-limited exercise testing with ventilatory expired gas analysis. Mean age and left ventricular ejection fraction for 44 male and 28 female subjects were 51.2 years (+/-13.0) and 27.0% (+/-12.3) respectively. The VE/VCO2 slope was calculated from time 0 to 25, 50, 75 and 100% of exercise time and subsequently used to create five randomly selected VE/VCO2 slope categories. RESULTS: (The intraclass correlation coefficient found calculation of the VE/VCO2 slope, when divided into quartiles, to be a reliable measure (alpha=0.94, P<0.0001). Univariate Cox regression analysis revealed all VE/VCO2 slope categories (25-100% and random selections) were significant predictors of cardiac-related hospitalization and mortality over a 1-year period. Multivariate Cox regression analysis revealed all VE/VCO2 slope categories outperformed peak oxygen consumption (VO2) in predicting hospitalization and mortality at 1 year. CONCLUSIONS: Although the different classification schemes were not identical, these results suggest VE/VCO2 slope maintains prognostic significance regardless of exercise-test time interval. Calculation of VE/VCO2 slope may therefore still be valuable in subjects putting forth a sub-maximal effort while effort-dependent measures, such as peak VO2, are not.

Adult↗

Cardiopulmonary exercise testing following hay exposure challenge in farmer's lung.

In patients experiencing an acute episode of hypersensitivity pneumonitis (HP), the alveoli and interstitium show a marked inflammation. The effects of this infiltration with effector cells on gas exchange and the cardiopulmonary system are not well characterized, and there are no data regarding cardiopulmonary exercise testing during hypersensitivity pneumonitis. The aim of this study was to gain new insights into the pathophysiology of acute farmer's lung using cardiopulmonary exercise testing. Cardiopulmonary exercise testing was performed in patients who had farmer's lung (n=21) before and 4 h after a standardized exposure with mouldy hay. Farmers who were asymptomatic for this condition (n=15) served as controls. At baseline, patients who had farmer's lung had a decreased breathing reserve and a greater alveolar to arterial oxygen difference. Following exposure, all of these patients developed hypersensitivity pneumonitis. Compared to the asymptomatic farmers, they showed an increase of alveolar to arterial oxygen difference and functional dead space ventilation during exercise and a reduction of the breathing reserve. In addition, 40% of the asymptomatic farmers demonstrated a pathological increase of the alveolar to arterial oxygen difference during exercise following exposure. In conclusion, our data signify that acute hypersensitivity pneumonitis induces significant changes in pulmonary gas exchange during exercise. Cardiopulmonary exercise testing may help to identify individuals with possible subclinical farmer's lung disease.

Adult↗

Reproducibility of cardiopulmonary exercise testing in men following myocardial infarction.

Peak oxygen consumption during progressive exercise is of clinical relevance in the functional evaluation of the cardiac patient. The use of cardiopulmonary exercise testing for the evaluation of the efficacy of therapeutic intervention requires that the methods used yield reproducible results. This study compared the results of two consecutive, symptom-limited, maximal exercise tests in 170 men following confirmed myocardial infarction. On-line, real-time respiratory gas exchange was measured on a breath-by-breath basis. The data were processed by the system using a 9 s moving average filter and the peak values were determined as averaged over a representative 20-s interval during the final 1 min of the test. The mean (+/- SD) total exercise times for the two tests were 635 (+/- 109) vs. 652 (+/- 112) (r = 0.946). The mean (+/- SD) peak VO2 values were 1480 (+/- 337) vs. 1495 (+/- 350) ml min-1 (r = 0.923). Performance could not be predicted by routine assessment of infarct type or size. This study demonstrates that maximal cardiopulmonary exercise testing in men following myocardial infarction yields highly reproducible results.

Adult↗

How much prognostic information do exercise test data add to clinical data after acute myocardial infarction?

We compared the prognostic significance of variables from a symptom-limited bicycle exercise test performed three weeks after acute myocardial infarction with clinical variables from the hospitalization utilizing discriminant function analysis for one year follow-up. Clinical exclusion criteria define a high-risk group of patients not eligible for exercise testing. Among 430 patients without test 28.4% died versus 6.6% among 456 patients with test (P less than 0.0001) and 21.4% versus 9.6% experienced a new infarction (P less than 0.001). The most important exercise test variables were duration of exercise and ventricular premature beats. The prediction of death was not significantly different when clinical variables, exercise test variables or the combined set were used for positive predictive value (66.7%, 60.0%, 63.3%) and negative predictive value (71.6%, 67.4%, 71.8%). For new infarction the positive predictive value was significantly higher for exercise test variables (56.8%, P less than 0.03) or the combined set (59.3%, P less than 0.02) compared to clinical variables (45.5%). The negative predictive value was significantly higher for clinical variables (79.6%) compared to exercise data (63.6%, P less than 0.0001) or the combined set (67.0%, P less than 0.001). We conclude that exercise data cannot improve prediction of death but provides higher positive predictive value for the prediction of new infarction.

Aged↗

Superiority of 24-hour outpatient monitoring over multi-stage exercise testing for the evaluation of syncope.

Twenty-four hour outpatient monitoring was compared with maximum multi-stage Treadmill exercise testing for the detection of dysrhythmias producing syncope or near syncope in 119 patients. All patients had cardiovascular disorders; only 21% had coronary artery disease. Patients with obvious cause of syncope and/or significant dysrhythmias by resting electrocardiograms (ECGs) were excluded. A significant dysrhythmia was found which was considered the probable cause of syncope or pre-syncope in 76 patients (64%). A non-cardiac cause was found in tachycardia, exercise testing identified only patients with complex ventricular dysrhythmias and missed 64% of these. Overall, dysrhythmias were found by ambulatory monitoring alone in 63 patients, by exercise testing alone in only three, and by both in 10. It is concluded that: 1) in the majority of patients with syncope or pre-syncope suspected to be of a cardiac origin, a dysrhythmia can be found; 2) ambulatory monitoring is far superior to exercise testing for detection of dysrhythmias; 3) exercise testing increases the yield for complex ventricular dysrhythmias.

Adolescent↗

Identifying which patients with diabetes should be tested for the presence of coronary artery disease--the importance of baseline electrocardiogram and exercise testing.

Numerous studies have reported that diabetic patients should not always be considered to be coronary artery disease (CAD)-equivalent as was previously suggested. Exercise testing is widely available at a relatively low cost, and even among patients in whom the diagnosis of CAD is highly probable on the basis of age, sex, description of chest pain and history of prior myocardial infarction, exercise testing is often a clinical requirement for risk or prognosis assessment to determine the need for possible coronary angiography or revascularization. Nevertheless, because of either the presence of atypical symptoms or the absence of symptoms often encountered, the screening approach may differ in patients with diabetes mellitus. Because CAD is the major cause of mortality in patients with diabetes, its early detection is important to improve medical interventions and outcomes. This is critical because the available evidence suggests that occult CAD is common among asymptomatic patients with diabetes. Therefore, noninvasive testing for asymptomatic CAD may be helpful for the identification of diabetic patients with severe coronary obstruction in whom revascularization therapy may be considered the first manifestation of silent CAD in patients with diabetes is a fatal cardiac event in approximately one-half of the patients. The present paper reviews some clinical markers that may be helpful to the clinician to increase the yield of finding significant occult CAD while screening patients with diabetes.

Coronary Artery Disease↗

Contribution of cardiopulmonary indices in the assessment of patients with silent and symptomatic ischemia during exercise testing.

Cardiopulmonary and radionuclear indices were used to evaluate and compare cardiac function during exercise testing in patients with symptomatic and silent ischemia. The study comprised 58 patients aged 35-74 years, divided into three groups: Group I-20 patients (controls) with neither ST depression nor chest pain; Group II-22 patients with ST depression > 1 mm and no chest pain; Group III-16 patients with both ST depression and chest pain. All patients in Groups II and III demonstrated significant coronary artery disease. No antianginal medication was taken at least 24 h before testing. All patients underwent a cardiopulmonary exercise test and a multigated acquisition radionuclear study. The following variables were measured: oxygen consumption (VO2), CO2 output (VCO2), minute ventilation (VE), O2-pulse, ventilatory anaerobic threshold (VAT), left ventricular ejection fraction (LVEF) at rest (r) and at maximal effort (ex). Probability values were significant for all variables (P < 0.01-0.0001) except left ventricular ejection fraction-rest (P not significant between the three groups). No significant differences in extent of coronary artery disease were noted between Groups II and III. These findings suggest that during exercise testing patients with silent ischemia have better overall cardiac function than patients with symptomatic ischemia. Their value for both cardiopulmonary and radionuclear indices are closer to those of the control group than to the symptomatic group, regardless of the severity of the coronary artery disease Summary of results: (mean +/- 1 S.D.) Group VO2-max O2-Pulse max VAT (%) VAT (ml/min) LVEF-rest delta LVEF (ex-r) I 25.2 +/- 6.3 15.7 +/- 3.4 51.2 +/- 6.6 1075 +/- 289 54.7 +/- 7 5.4 +/- 4.85 II 22.4 +/- 2.8 14.5 +/- 2 47.0 +/- 5.3 854 +/- 136 52 +/- 10 1.2 +/- 6.7 III 16.0 +/- 2.5 11.4 +/- 2 41.6 +/- 7.7 683 +/- 105 51 +/- 8.5 -5.87 +/- 6.3

Adult↗

Decrease in systolic blood pressure during exercise testing: reproducibility, response to coronary bypass surgery and prognostic significance.

To investigate the reproducibility and prognostic significance of an exercise-induced decrease in systolic blood pressure, 47 patients were identified who manifested such a reduction below the pre-exercise standing level in a consecutive series of 436 patients who underwent treadmill exercise testing and cardiac catheterization during a 3 year period. The prevalence of this abnormal finding was 11 percent in the total group but 21 percent in the 124 patients with three vessel or left main coronary artery disease. Patients with an exercise-induced reduction in systolic blood pressure were more likely to be male, have typical angina pectoris with class III or IV functional limitation and to have had a prior myocardial infarction than were patients without this finding (p less than 0.05). Although no complications occurred during the exercise test of these 47 patients, the majority had severe ischemic responses and 14 (30 percent) showed complex repetitive ventricular arrhythmias. Of the 47 patients, 24 (group 1a) received medical treatment and 23 (group 1b) underwent coronary bypass surgery. On repeat exercise testing in 42 patients, a decrease in systolic blood pressure during exercise was consistently present in group 1a (17 of 20) but entirely absent (0 of 22) in group 1b (p less than 0.001). The mean treadmill time, peak heart rate and systolic blood pressure were not significantly different in the initial and on repeat exercise tests in patients in group 1a; however, in patients in group 1b, all of these variables were significantly higher in the repeat test (p less than 0.001). At a mean follow-up time of 37 months, the total cardiac mortality rate was 8 percent (2 of 24) in group 1a and 4 percent (1 of 23) in group 1b. It is concluded that a decrease in systolic blood pressure during exercise testing is highly reproducible and appears to be reversed by coronary bypass surgery.

Angina Pectoris↗

Long-term value of exercise testing after acute myocardial infarction: influence of thrombolytic therapy.

OBJECTIVES: To evaluate the long-term predictive value of exercise testing performed early after acute myocardial infarction (AMI) in patients receiving thrombolytic therapy. DESIGN: Nonblinded prospective follow-up study. SETTING: Cardiac rehabilitation unit in a 900-bed university hospital. SUBJECTS: Four hundred forty-three patients allowed to perform exercise testing 3 weeks after AMI were followed for a median of 75 months; 183 received IV thrombolysis and 263 did not. RESULTS: Cardiac death hazard ratios were significantly increased in the presence of reduced physical working capacity on exertion, left ventricular dysfunction, and > or = 1-mm (but < 2-mm) ST-segment depression on exertion. In the group receiving thrombolytic therapy, no patient with > or = 2-mm ST-segment depression on exercise died; this group was characterized by a high rate of revascularization, whereas the group with > or = 1-mm but < 2-mm ST-segment depression was not. No parameter related to clinical or exercise testing predicted recurrent infarction in the group receiving thrombolytic therapy. Among patients not receiving thrombolysis, cardiac death was significantly related to > or = 2-mm ST-segment depression on exertion, to reduced physical working capacity, and to the lack of revascularization during follow-up. CONCLUSION: Exercise test-derived parameters have variable value in predicting long-term survival of patients performing exercise test after AMI depending on the following: (1) whether thrombolytic therapy was given or not; (2) the degree of ST-segment depression during exercise testing; and (3) the rate of revascularization.

Adult↗

A consensus approach to diagnosing coronary artery disease based on clinical and exercise test data.

OBJECTIVE: To demonstrate that a consensus approach for combining prediction equations based on clinical and exercise test variables derived from different populations can stratify patients referred for possible coronary artery disease (CAD) into low-, intermediate-, and high-risk groups. DESIGN: Retrospective analysis of consecutive patients with complete data from exercise testing and coronary angiography referred for evaluation of possible CAD. After derivation of a logistic equation in our own training set of patients, this equation, along with two other equations developed independently by other investigators, was validated in a test set. The validation strategy for the consensus approach included the following: (1) calculation of probability scores for each patient using each logistic equation independently; (2) determination of probability thresholds in the training set to divide the patients into three groups-low risk (prevalence CAD <5%), intermediate risk (5 to 70%), and high risk (>70% prevalence of CAD); (3) using agreement among at least two of three of the prediction equations to generate "consensus" for each patient; and (4) application of the consensus approach thresholds to the test set of patients. SETTINGS: Two university-affiliated Veteran's Affairs medical centers. PATIENTS: We studied 718 consecutive men between 1985 and 1995 who had coronary angiography within 3 months of an exercise treadmill test for suspected CAD. The population was randomly divided into a training set of 429 patients and a test set of 289 patients. Patients with previous myocardial infarction or coronary artery bypass surgery, valvular heart disease, left bundle branch block, or any Q waves present on their resting ECG were excluded from the study. MEASUREMENTS: Recording of clinical and exercise test data along with visual interpretation of the ECG recordings on standardized forms and abstraction of visually interpreted angiographic data from clinical catheterization reports. RESULTS: We demonstrated that by using simple clinical and exercise test variables, we could improve on the standard use of ECG criteria during exercise testing for diagnosing CAD. Using the consensus approach divided the test set into populations with low, intermediate, and high risk for CAD. Since the patients in the intermediate group would be sent for further testing and would eventually be correctly classified, the sensitivity of the consensus approach is 94% and the specificity is 92%. The consensus approach controls for varying disease prevalence, missing data, inconsistency in variable definition, and varying angiographic criterion for stenosis severity. The percent of correct diagnoses increased from the 67% for standard exercise ECG analysis and from the 80% for multivariable predictive equations alone to >90% correct diagnoses for the consensus approach. CONCLUSIONS: The consensus approach has made population-specific logistic regression equations portable to other populations. Excellent diagnostic characteristics can be obtained using simple data and measurements. The consensus approach is best applied utilizing a programmable calculator or a computer program to simplify the process of calculating the probability of CAD using the three equations.

Coronary Angiography↗

[Comparison of prognostic value of high-dose dobutamine stress-echocardiography and exercise testing in patients with idiopathic dilated cardiomyopathy].

INTRODUCTION: It is of the utmost importance to make an accurate assessment of prognosis in patients with idiopathic dilated cardiomyopathy. Both high-dose dobutamine stress-echocardiography and exercise testing have been used for prognostic stratification of these patients. OBJECTIVE: To make head-to-head comparison of high-dose dobutamine stress-echocardiography and exercise testing in prognostic stratification of patients with idiopathic dilated cardiomyopathy. METHODS: A total of 63 consecutive patients (55 men, mean age 50.1 +/- 9.6 years, mean ejection fraction 19.2 +/- 8.4%) with idiopathic dilated cardiomyopathy, left ventricular end-diastolic diameter >60mm, ejection fraction <35%, and adequate echocardiographic window have been studied. Dobutamine stress echocardiography was performed using 5, 10, 20, 30 and 40 mcg/kg/min infusions, in progressive stages lasting 5 minutes each. Wall motion score index and ejection fraction were considered the indices of the left ventricular contractility. Contractile reserve was defined as the difference between the values of these indices obtained at peak dobutamine dose during the test and the baseline values. Exercise testing was performed as supine bicycle ergometry in progressive stages of 25 W lasting 120 seconds each. Patients were followed one year for combined end-point consisting of cardiac death, partial left ventriculectomy and hospitalization for congestive heart failure. RESULTS: Out of 61, 19 (31%) patients met combined end-point during follow-up [cardiac death in 6/61 (10%), partial left ventriculectomy in 4/61 (7%) and hospitalization for heart failure in 9/61 (15%) patients]. Kaplan-Meier survival analysis demonstrated that dobutamine-induced change of wall motion score index was the best parameter for separation of patients in terms of prognosis during the follow-up (log rank=25.34, p<0.001), followed by change of ejection fraction (log rank=16.83, p<0.001) and duration of exercise testing (log rank 13.85, p=0.002). Cox model identified dobutamine-induced change of wall motion score index as the only independent predictor (p<0.001) of combined end-point during one-year follow-up. DISCUSSION: There is a number of studies dealing with the left ventricular contractile indices. These studies are different with respect to studied population, method used to elicit the left ventricular contractile response and the indices of contractile reserve. A number of studies has suggested that the amount of pharmacologically or physically induced change of wall motion score index and ejection fraction can identify patients with dismal prognosis. Peak oxygen consumption is traditionally considered the most accurate prognostic index, but its usefulness has been recently questioned. Our data suggest that high-dose dobutamine stress-echocardiography may be superior to exercise testing for prognostic stratification of patients with idiopathic dilated cardiomyopathy. The reasons for such observation are not clear, but it can be hypothesized that this may be due to multifactorial nature of the exercise tolerance. The most serious potential drawback of methodology is that, because of technical limitations, we did not test peak oxygen consumption in our patients, but since it has been shown that oxygen consumption correlates well with the duration of exercise, we believe that our methodology is valid. CONCLUSION: Both high-dose dobutamine stress-echocardiography and exercise testing can identify patients with dismal prognosis during one-year follow-up, but it appears that dobutamine stress-echocardiography may yield better prognostic significance.

Cardiomyopathy, Dilated↗

Prolonged exercise testing in two children with a mild Multiple Acyl-CoA-Dehydrogenase deficiency.

BACKGROUND: Multiple Acyl-CoA-Dehydrogenase deficiency (MADD) is an inherited metabolic disorder characterized by impaired oxidation of fatty acids and some amino acids. METHODS: We were interested whether children with MADD could tolerate a prolonged low-intensity exercise test and if this test could have any additional diagnostic value. Therefore, we performed a maximal exercise test and a low-intensity prolonged exercise test in 2 patients with MADD and in 5 control subjects. During a prolonged exercise test the subjects exercised on a cycle ergometer at a constant workload of 30% of their maximum for 90 minutes and heart rate, oxygen uptake, fuel utilization and changes in relevant blood and urinary parameters were monitored. RESULTS: The tests were tolerated well. During the prolonged exercise test the fatty acid oxidation (FAO) was quite low compared to 5 control subjects, while characteristic metabolites of MADD appeared in plasma and urine. CONCLUSION: We suggest that the prolonged exercise test could be of diagnostic importance and might replace the fasting test as a diagnostic procedure in some cases, particularly in patients with anamnestic signs of intolerance for prolonged exercise.

Journal Article↗

[Accuracy of the Master's exercise test in detecting significant coronary artery disease].

To assess the significance and accuracy of noninvasive tests in detecting significant coronary artery disease (CAD; greater than 50% stenosis), the Master's exercise test, treadmill exercise test and dipyridamole-loading myocardial perfusion scintigraphy were performed and their results were compared with coronary angiographic findings in 60 patients with angina but without myocardial infarction. Among these, 27 patients had significant CAD. The Master's test performed in outpatient clinics had an 85% sensitivity and a 76% specificity in detecting significant CAD, when the degree of ST depression was equal to or exceeded 1 mm. The sensitivity further improved to 96% by adding chest pain to the criteria; then all patients with multivessel disease or critical ischemia were identified by the Master's test. Treadmill tests performed after admission had a 78% sensitivity and a 67% specificity. When the severity of ischemia was judged either by exercise capacity or the degree of ST depression or the coronary T wave, the treadmill test was superior to the Master's test. Although patients without significant CAD had longer exercise capacity and the higher maximum heart rate in the treadmill test than did those in the Master's test, these trends were similar but less marked in patients with significant CAD. Dipyridamole-loading myocardial perfusion scintigraphy showed an excellent sensitivity and specificity; 96% and 94%, respectively, in detecting significant CAD. It was particularly useful in distinguishing false positive exercise results due to left ventricular hypertrophy and coronary spasm and that in women, from true positive results. In conclusion, the Master's test is a simple and useful method for screening CAD in community hospitals and in outpatient clinics.

Adult↗

Maximal exercise test results in subacute stroke.

OBJECTIVES: To establish the feasibility and reliability of graded maximal exercise testing, suitability of standard indexes of maximum oxygen consumption (Vo(2)max), and evidence of trial-to-trial practice effects in subacute stroke. DESIGN: Descriptive, cross-sectional study. SETTING: Rehabilitation hospital. PARTICIPANTS: Consecutive sample of 35 participants (mean age, 65.7+/-2.6 y; mean days poststroke, 17.6+/-2.2 d). INTERVENTIONS: Not applicable. MAIN OUTCOME MEASURES: Graded maximal exercise test using semirecumbent cycle ergometry. A subset (n=20) performed repeated tests to determine test-retest reliability and presence of practice effects. RESULTS: Thirty-one (89%) participants completed the exercise test without symptomatic responses (mean peak level of oxygen consumed [Vo(2)peak], 10.7 mL.kg(-1).min(-1); peak work rate, 39 W). Twelve (34%), 15 (44%), and 3 (9%) participants achieved oxygen consumption per unit time (Vo(2)) plateau, respiratory exchange ratio, and heart rate criteria, respectively. Although test-retest correlations were high (intraclass correlation coefficient range, .67-.87), higher Vo(2)peak (1.0 mL.kg(-1).min(-1), P=.04) and work rate (7.3 W, P=.01) were observed with repeated testing, with no associated increase in reaching standard criteria for Vo(2)max. CONCLUSIONS: This work has important implications for developing guidelines for measuring aerobic capacity early after stroke. Although maximal exercise testing using semirecumbent cycle ergometry is feasible, standard Vo(2)max criteria are not consistently appropriate. At least 1 practice trial is recommended before the actual evaluation is performed.

Adult↗

Prediction of morbidity after lung resection with risk factors using treadmill exercise test.

OBJECTIVE: To predict accurate morbidity after lung resection using treadmill exercise test. METHODS: A total of 130 patients (108 men and 22 women, with mean age 67.1+/-11.4 years (range, 34-78 years)) of 1129 patients underwent standard lobectomy were performed both treadmill exercise test and spirometry preoperatively. We measured maximum oxygen uptake/body weight (VO2max/BW) and change in arterial blood oxygen pressure from rest to symptom-limited maximum loading (delta aPaO2) and calculated exercise-induced hypoxemia (delta PaO2/delta VO2/BW), and retrospectively compared these parameters for patients with and without complications. RESULTS: There were five patients with severe postoperative complications, including three requiring use of a respirator, two with home oxygen therapy. %Vital capacity, VC (%, 80.2+/-13.2 vs. 92.5+/-20.9, P=0.026), delta PaO2 (Torr, -29.3+/-4.3 vs. -13.2+/-10.8, P=0.0004), VO2max/BW (ml/min/kg, 16.5+/-2.9 vs. 20.6+/-5.1, P=0.018) and delta PaO2/delta VO2/BW (Torr/ml/min/kg, -1.98+/-0.26 vs. -0.57+/-0.47) were significantly associated with worse outcome. All the five patients with complications had delta PaO2/delta VO2/BW<-1.7. CONCLUSIONS: Treadmill exercise testing is a good method for assessment of cardiopulmonary reserve. Limited resection must be performed if delta PaO2/delta VO2/BW is under -1.7.

Adult↗

Propranolol therapy alters estimation of potential cardiovascular risk derived from submaximal postinfarction exercise testing.

We studied the effect of propranolol administration on risk assessment based on submaximal exercise testing performed early after myocardial infarction. A total of 70 patients with recent infarction underwent modified Bruce treadmill testing with simultaneous measurement of expired gases in the absence of antianginal agents including beta-antagonists. Among these, 31 patients who had at least one of the following abnormalities--ST depression greater than or equal to 1 mm (22 patients), chest pain (four patients), or treadmill time less than 360 seconds (12 patients)--were studied in a randomized double-blind fashion and received either placebo or 240 mg of propranolol/day. A total of 28 patients completed the randomized phase and were able to undergo repeat exercise testing an average of 3.4 +/- 1.8 days later. Randomized groups were equivalent at baseline except for a higher peak oxygen consumption and carbon dioxide production (p less than 0.05) in the propranolol compared with the placebo group; these differences were taken into account in statistical analyses of the study data. Resting heart rate (59 +/- 1.2 versus 82 +/- 4.2 beats/min) and peak heart rate x systolic blood pressure (14,208 +/- 496 versus 20,075 +/- 1,062) were both significantly less (p less than 0.01) after propranolol than after placebo. Eight of nine patients treated with placebo maintained ST depression greater than or equal to 1 mm from the initial to the randomized exercise test, compared with only 4 of 13 receiving propranolol (p less than 0.01). In those with continued ST depression, time to positivity was significantly longer in those receiving propranolol compared with those taking placebo (538 +/- 73 versus 318 +/- 44 seconds, p less than 0.05). In contrast, the peak ratio between carbon dioxide production and oxygen consumption was higher in those receiving propranolol compared with those receiving placebo (0.93 +/- 0.04 versus 0.81 +/- 0.03, p less than 0.05). We conclude that propranolol therapy reduces evidence of ischemia and changes traditional estimates of potential cardiac risk derived from submaximal postinfarction exercise testing.

Cardiovascular Diseases↗

Increased albumin excretion rate during a standardized exercise-test in diabetics with lowered blood filterability.

Albumin excretion rate in urine is a marker of early, reversible stages of diabetic nephropathy. Does abnormal blood rheology represent an additional risk factor in this multifactorial process? We investigated a possible link between red cell filterability and microalbuminuria during an exercise test (exercise is supposed to improve the detection of excessive microalbuminuria). 77 diabetics (27 females, 50 males, age: 15-60 yr) underwent a 20 min inframaximal progressively increasing workload on cycloergometer, rising heart rate up to 200 minus the age. Filterability of whole blood and washed red cells were measured on 5 microns polycarbonate sieves reused after ultrasonic cleaning. Whole blood filterability was found to be impaired in 35 subjects (group A) and normal in 41 (group B). Groups A and B were matched for age, sex, blood pressure, glycemic equilibrium, and duration of disease. Microalbuminuria was higher in A at rest (39.79 +/- 13.83 micrograms/min vs 12.9 +/- 3.21, p less than 0.01) and after exercise (91.80 +/- 20.79 vs 42.23 +/- 7.85, p less than 0.01). The slopes of regression lines between resting Microalbuminuria and blood pressure were greater in group A than in group B (p less than 0.01). No relationship between microalbuminuria and washed red cell filterability was detected. This study confirms on a larger scale a previous report of our team. Some hemorheologic disorders detectable with whole blood filterability (but not with washed red cell filtration) are associated with an increase in resting and postexercise microalbuminuria.

Adolescent↗