Cardiorespiratory Exercise Testing Research Articles

Physical training modulates proinflammatory cytokines and the soluble Fas/soluble Fasligand system in patients with chronic heart failure

ObjectivesWe sought to investigate the effects of physical training on circulating proinflammatory cytokines and the soluble apoptosis mediators Fas (sFas) and Fas ligand (sFasL) in patients with chronic heart failure (CHF). BackgroundRecent investigations have shown an overexpression of circulating proinflammatory cytokines and soluble apoptosis mediators in patients with CHF, which may be related to their exercise intolerance and clinical deterioration. MethodsPlasma levels of tumor necrosis factor-alpha (TNF-alpha), soluble TNF receptors I and II (sTNF-RI and sTNF-RII, respectively), interleukin-6 (IL-6), soluble IL-6 receptor (sIL-6R), sFas and sFasL were measured in 24 patients with stable CHF (New York Heart Association functional class II/III; left ventricular ejection fraction 23.2 ± 1.3%) and in 20 normal control subjects before and after a 12-week program of physical training in a randomized, crossover design. Functional status of patients with CHF was evaluated by using a cardiorespiratory exercise test to measure peak oxygen consumption (Vo2max). ResultsPhysical training produced a significant reduction in plasma levels of TNF-alpha (7.5 ± 1.0 pg/ml vs. 4.6 ± 0.7 pg/ml, p < 0.001), sTNF-RI (3.3 ± 0.2 ng/ml vs. 2.7 ± 0.2 ng/ml, p < 0.005), sTNF-RII (2.6 ± 0.2 ng/ml vs. 2.3 ± 0.2 ng/ml, p = 0.06), IL-6 (8.3 ± 1.2 pg/ml vs. 5.9 ± 0.8 pg/ml, p < 0.005), sIL-6R (34.0 ± 3.0 ng/ml vs. 29.2 ± 3.0 ng/ml, p < 0.01), sFas (5.5 ± 0.7 ng/ml vs. 4.5 ± 0.8 ng/ml, p = 0.05) and sFasL (34.9 ± 5.0 pg/ml vs. 25.2 ± 4.0 pg/ml, p < 0.05), as well as a significant increase in Vo2max (16.3 ± 0.7 ml/kg per min vs. 18.7 ± 0.8 ml/kg per min, p < 0.001). Good correlations were found between a training-induced increase in Vo2max and a training-induced reduction in levels of the proinflammatory cytokine TNF-alpha (r = −0.54, p < 0.01) and the apoptosis inducer sFasL (r = −0.57, p < 0.005) in patients with CHF. In contrast, no significant difference in circulating cytokines and apoptotic markers was found with physical training in normal subjects. ConclusionsPhysical training reduces plasma levels of proinflammatory cytokines and the sFas/sFasL system in patients with CHF. These immunomodulatory effects may be related to the training-induced improvement in functional status of patients with CHF.

Pulmonary function tests, aerobic capacity, respiratory muscle strength and endurance of patients with rheumatoid arthritis.

Patients with rheumatoid arthritis (RA) show lower cardiorespiratory fitness than normal subjects. This study was planned to investigate the pulmonary function tests (PFT), respiratory muscle strength and endurance, and aerobic capacity of patients with RA, as well as the relationship of these parameters to clinical and functional status. Twenty-five RA patients aged 25-71 (48.52 +/- 14.09) and 21 control subjects aged 25-66 (45.67 +/- 13.27) participated in the study. PFT, maximum volunteer ventilation, maximum inspiratory and maximum expiratory pressures and cardiorespiratory exercise tests were carried out in all subjects to evaluate the respiratory involvement, inspiratory and expiratory muscle strength and endurance, and aerobic capacity. Patients' duration of disease, smoking and alcohol habits, duration of morning stiffness, visual analogue scale scores, ARA functional classifications and Ritchie articular indexes were recorded. All the patients and control subjects were non-exercising individuals. As a result, we found that RA patients have normal PFT but reduced respiratory muscle strength and endurance, and also reduced aerobic capacity compared to controls. According to this result, respiratory and aerobic exercises may be recommended to improve respiratory muscle strength and endurance and aerobic capacity in these patients.

Comparison of usefulness between exercise capacity and echocardiographic indexes of left ventricular function in cardiac amyloidosis

In patients with primary systemic amyloidosis (AL), the echocardiographic assessment of ventricular function alone does not always correspond to patients’ symptoms and functional status. Peak oxygen uptake and anaerobic threshold (AT), in contrast, constitute 2 objective, reliable and reproducible indicators of functional status in patients with circulatory failure. Thirty-two consecutive patients (mean age 50 ±13 years) with histologic evidence of systemic primary AL were studied (29 AL, 3 hereditary). There were 16 with echocardiographic features of cardiac infiltration (group I) and 16 without (group II). Twenty age- and gender-matched healthy subjects were also studied for comparison. Of the 32 patients, 12 were in New York Heart Association functional class I, 9 were in class II, and 11 were in class III. Each subject underwent 2-dimensional and Doppler echocardiography and cardiopulmonary exercise testing using a modified Bruce protocol. Left atrial (LA), left ventricular (LV) dimensions, wall thickness, and LV fractional shortening, as well as transmitral flow velocities and their E/A ratio were measured. Peak oxygen consumption (VO 2max [ml/kg/min]), AT (ml/kg/min), and exercise duration (seconds) were also measured. VO 2max and AT were lower in patients with AL than in controls (20.8 ± 7.0 vs 35.0 ± 8.5, p <0.001 and 13.1 ± 3.7 vs 27.0 ± 4.2, p <0.001, respectively). As a group, symptomatic patients had lower VO 2max, AT, and exercise duration than those without symptoms (17.1 ± 3.6 vs 27.0 ± 6.9, p = 0.0001, 11.1 ± 2.1 vs 16.2 ± 3.6, p = 0.0001, and 489 ± 235 vs 843 ± 197, p = 0.0001, respectively), whereas LV dimensions only showed a small difference (p = 0.03). VO 2max, AT, and exercise duration of patients in functional class I were higher than those in functional classes II and III (p = 0.01, p <0.05, and p = 0.007, respectively). Asymptomatic patients had lower VO 2max, AT, and exercise duration than controls (p <0.0001). VO 2max, AT, and exercise duration were poorly related to LA diameter, LV dimensions, fractional shortening, wall thickness, peak velocities of E and A waveforms, and E/A ratio. Patients with VO 2max >15 ml/kg/min had a better survival than patients with VO 2max <15 ml/kg/min. Thus, in patients with primary systemic AL, cardiorespiratory exercise testing is the preferred way of assessing functional capacity. Echocardiographic Doppler indexes at rest are not predictive of a patient’s symptoms and exercise capacity. Furthermore, VO 2max is a strong independent predictor of survival in these patients.

Clinical Exercise Testing - Expanding Utility Beyond the 1990's.

799 This symposium will present perspectives on current research related to exercise testing with patients who have suspected or known coronary artery disease (CAD), congestive heart failure (CHF), or certain chronic obstructive pulmonary diseases (COPD). Cardiorespiratory exercise testing continues to be a widely utilized stand-alone procedure in the clinical setting, even apart from its substantial use in conjunction with stress imaging technologies. With appropriately selected patients, it carries a very low risk of serious complications, has documented diagnostic value, and is relatively inexpensive to administer. The symposium will focus on the research evidence related to the following issues: 1) prognosis with CAD patients, particularly with approaches that use multivariate prediction models derived from physiological and clinical responses to exercise; 2) prognosis with CHF patients, based upon criteria obtained from cardiorespiratory exercise variables; 3) understanding diagnostic implications of exercise testing, as a result of recent advances in quantification of CAD by angiography; 4) prognosis with CAD patients, based on the finding of chronotropic impairment during exercise; 5) understanding of functional limitations with COPD patients; and 6) assessment of CAD patients in the setting of exercise rehabilitation.

A new method for data presentation in incremental cardiorespiratory exercise testing.

In incremental cardiopulmonary exercise testing, the averaging of data is usually performed to provide group mean data for statistical purposes. They are usually presented as averaged maximum values, or as averaged data at different exercise levels. However, during incremental exercise testing the change in metabolic status may vary between subjects, thus averaging data may not classify the metabolic status accurately. We present an averaging method using a segmented ordinal scale based on individual maximal work performance and the anaerobic threshold (AT). Individual exercise data are grouped into ten classes ranging from unloaded exercise to maximal exercise. The classes are defined in relation to the AT, resulting in an ordinal scale of four classes for exercise data below the AT, one class at the AT and five classes beyond the AT. Resting and unloaded pedalling are treated as separate classes. For evaluation, this method of classification is compared to one based on an absolute scale of oxygen uptake (Cabs) and to another based on a relative scale in 10% steps of maximal oxygen uptake (Crel). Ten healthy male subjects (mean age 23.3 years) performed a ramp cycle ergometer test. When using the Cabs classification method for mean data averaging, mean values for performance at high-intensity exercise were calculated using data from only two of the ten subjects because of variations in individual work capacity. In addition, the AT data were distributed across four classes, thus anaerobic and aerobic exercise data were mixed. Using the Crel classification method enabled data for all ten subjects to be included in the calculation of every data point, but the AT values were still distributed across three classes, resulting in the mixing of anaerobic and aerobic exercise data. However, using the segmented ordinal scale method of classification enabled data from all ten subjects to be included in the calculation of all data points, and it permitted the grouping of the AT values into one class. Thus, this latter method more accurately represents the data of the whole group under study and it allows the metabolic status of the subjects to be taken into consideration.

Analysis of fetal and neonatal urine using proton nuclear magnetic resonance spectroscopy.

To use high field proton nuclear magnetic resonance spectroscopy (1H NMR) to characterise the low molecular weight metabolite composition of neonatal and fetal urine in relation to gestational age and perinatal outcome. The first urine passed by two neonatal groups, six full term and five preterm infants with normal renal function, was analysed by 1H NMR and compared with fetal urine from 14 cases with obstructive uropathy. The mean ratios of taurine, myo-inositol, and trimethylamine-N-oxide (TMAO) to creatinine were 4.3, 10.1, and 14.1 times higher, respectively, in the preterm group when compared with those of the full term group. Fetal obstructive uropathy was characterised by glycosuria, amino and organic aciduria, regardless of gestational age (13-30 weeks). Samples of the first urine passed--that is, urine produced in fetal life--by normal preterm infants are useful controls for cases of obstructive uropathy detected in the third trimester. 1H NMR will become a clinically useful tool for monitoring renal development and abnormalities in utero.

Can an echocardiographic score predict who will benefit clinically from balloon dilation of the mitral valve?

Deciding whether a patient with sub-optimal mitral valve anatomy will benefit from percutaneous mitral valvotomy remains a demanding clinical problem. We assessed the ability of an established echo score applied to transoesophageal images to predict absolute increases in mitral valve area and improvement in exercise capacity. Twenty five consecutive patients undergoing routine percutaneous mitral valvotomy were studied. Changes in exercise tolerance were measured by serial cardiorespiratory treadmill exercise testing. Before the procedure, exercise duration was directly related to mitral valve area ( r s = 0.44, P < 0.05). Following percutaneous mitral valvotomy there was an increase in valve area (0.9 ± 0.2 to 1.4 ± 0.3 cm 2, P < 0.0001) and repeat exercise testing demonstrated increases in exercise duration (470 ± 220 to 610 ± 240 s, P < 0.001) and peak VO 2 (12.6 ± 4.2 to 15.1 ± 4.5 ml/kg/min, P < 0.01). There was an inverse correlation between the echo score and the increase in valve area ( r s = −0.52, P < 0.05) but no relationship between the echo score and the increase in exercise duration or peak minute oxygen consumption (V O 2 ). These data demonstrate that a score applied to transoesophageal images echocardiographic images can predict changes in mitral valve area but that the score fails to predict functional improvement for an individual patient. This suggests, therefore, that patients without contraindications to valvotomy whose valves have a high echo score should still be considered for valvotomy as they may benefit considerably from the procedure.

Serial cardiorespiratory exercise testing in patients with congenital heart disease.

Aerobic capacity of patients with different forms of congenital heart disease was serially evaluated in 79 patients and the evolution was correlated with the lesion and the level of daily activity. The patients were divided into six groups: patients with a small ventricular septal defect (VSD) with mini shunt (n = 14), mild pulmonary valve stenosis with gradient < 40 mm Hg (PS) (n = 12), mild to moderate aortic valve stenosis (gradient 36 +/- 17 mmHg) (AS) (n = 12), patients 4.7 +/- 2.1 years after repair of tetralogy of Fallot (PO-TF) (n = 16), patients 2.2 +/- 2.9 years after closure of a high flow/high gradient VSD (PO-VSD) (n = 13), and patients 2.6 +/- 1.7 years after Fontan repair (Fontan-PO) (n = 12). Aerobic capacity was assessed by determination of the ventilatory anaerobic threshold (VAT). VAT reflects the highest aerobic exercise level prior to a disproportionate increase of CO2 and ventilation relative to O2 uptake; it is independent of patient motivation. Data are expressed as percentage of normal O2 uptake at VAT, determined in 234 age/gender matched controls. The habitual level of physical activity was assessed by a standardised questionnaire. Aerobic capacity in all subgroups of patients, even with very mild defects, was at or below the lower limit of normal. Children left unrestricted from physical exercise (VSD, PS, PO-VSD) had no change over the study period. However, aerobic capacity of patients with medically imposed physical restrictions (AS) and significant residual haemodynamic lesions (PO-TF, Fontan) decreased with age.(ABSTRACT TRUNCATED AT 250 WORDS)

Cardiorespiratory Responses to Incremental Exercise in Sarcoidosis Patients With Normal Spirometry

Patients with sarcoidosis are known to have histologic pulmonary abnormalities despite normal lung fields or conventional pulmonary function or both. These patients permit a useful assessment of the alleged greater sensitivity of the various measurements made during incremental cardiorespiratory exercise testing. Abnormal responses on such testing may provide insight into such complaints as dyspnea in these patients. Incremental exercise testing was performed on 30 patients with biopsy-proven sarcoidosis who had normal spirometry; 13 had clear lung fields radiographically. Of these patients, the 21 who had normal single-breath diffusing capacity for carbon monoxide (Dsb; [group A]) were compared with the 9 who had decreased Dsb (group B). Half of the group A patients had excessive ventilation and 38% had increased dead space to tidal volume ratio (Vd/Vt), but frequencies of these abnormalities were greater in group B, 89 and 78%, respectively. Ventilatory response, as minute ventilation to oxygen consumption ratios ventilatory equivalents, and deadspace to tidal volume ratio (Vd/Vt) ratios were higher in group B. Widened alveolar-arterial oxygen pressure differences were seen in 7 of 9 group B patients but only 1 of 17 group A patients. This study supports the clinical impression that occult pulmonary impairment may be present in patients (in this case, sarcoidosis patients) with normal pulmonary function, and corroborates the utility of exercise testing in demonstrating such impairment. Reduction in Dsb predicted greater frequency of abnormal exercise responses, especially in oxygenation.

Cardiorespiratory Responses to Incremental Exercise in Patients With Asbestos-related Pleural Thickening and Normal or Slightly Abnormal Lung Function

An increasing number of patients with asbestos exposure are being identified with pleural thickening (PT) alone, with little or no impairment in standard tests of lung function despite their frequent complaint of dyspnea. We have employed incremental cardiorespiratory exercise testing to evaluate the types and mechanisms of impairment in 23 such patients. All had normal lung fields on radiographic examinations and normal (group 1, n = 12) or minimally reduced (group 2A slight restriction, n = 5, group 2B, slight obstruction, n = 6), lung function. Excessive ventilation was common in all groups, but especially in group 2B. Abnormal dead space ventilation (VD/VT) was more frequent in groups 2A (4/5) and 2B (4/6) than in group 1 (3/12). It was associated with O2 desaturation in three patients in groups 2A and B. Cardiovascular abnormalities were rare (1/23). Excessive ventilation and dead space provide a basis for the symptom of dyspnea in these patients.

Cardiorespiratory fitness and exercise testing in patients with Kawasaki syndrome

Cardiorespiratory fitness and exercise testing in patients with Kawasaki syndrome

Cardiorespiratory exercise testing after venous switch operation in children with complete transposition of the great arteries

In 14 children who underwent a venous switch operation for complete transposition of the great arteries, exercise testing was performed 3 to 15 years (mean 8) after the operation. Exercise performance capacity was assessed by the determination of the ventilatory threshold during exercise and by the oxygen uptake (V̇O 2) reached at a heart rate of 170 beats/min (V̇O 2, 170). The ventilatory threshold was defined as the highest oxygen uptake (V̇O 2) at which the pulmonary ventilation (V̇ E) stops to increase linearly when related to V̇O 2. During exercise above this threshold a disproportionate increase in V̇ E relative to V̇O 2 is observed. The mean ventilatory threshold was significantly lower (p < 0.01) than the normal mean value and averaged 72 ± 15%, 67 ± 15% and 70 ± 13% of the predicted normal value for children of comparable age, weight and height, respectively. The mean value for V̇O 2, 170 also was significantly lower (p < 0.05) than the normal mean value for children of comparable age, weight and height, and averaged 81 ± 20%, 81 ± 18% and 80 ± 18%, respectively. Compared with normal control subjects of the same sex and age, the ventilatory threshold was surpassed sooner (p < 0.001) and reached after 2 ± 1 min instead of the 4 ± 1 min required by the controls. In nearly half of the patients, a lower than normal (i.e. below the 95% confidence limit) heart rate response to exercise was observed. Theoretically, this could be interpreted as indicating a normal or high physical performance capacity. However, the ventilatory threshold was subnormal in all but 1 of these patients. The blunted heart rate response observed in many patients after a venous switch operation suggests sinoatrial dysfunction secondary to extensive intraatrial operation.