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PubMed1985

Effect of labetalol on exercise tolerance and double product in mild to moderate essential hypertension.

Maximal exercise capacity after control of resting blood pressure with labetalol was studied in nine hypertensive men aged 34 to 69 years (average 52 years). Subjects exercised to exhaustion on an upright cycle ergometer with workload increased as a step function by 25 watts every three minutes, both before and after control of blood pressure was obtained. Mean exercise capacity expressed as total time of exercise until exhaustion was 936 seconds prior to control of the resting blood pressure and 884 seconds (no significant difference) after control of resting blood pressure with labetalol. Double product at peak exercise fell from 254 X 10(2) mm Hg beats per minute prior to blood pressure control to 183 X 10(2) mm Hg beats per minute (p = 0.006) after control of blood pressure with labetalol. The difference in the means of resting heart rate and both peak blood pressure and peak heart rate with exercise were all statistically significant after control of blood pressure with labetalol. These findings suggest that labetalol has an ideal exercise profile affording a cardioprotective effect by decreasing double product but without sacrificing exercise capacity.

Adult↗
PubMed2005

Granulocyte colony-stimulating factor-induced blood stem cell mobilisation in patients with chronic heart failure--Feasibility, safety and effects on exercise tolerance and cardiac function.

Bone marrow-derived stem cells may contribute to the regeneration of non-haematopoietic organs. In order to test whether an increase in circulating stem cell numbers improves impaired myocardial function we treated 16 male patients with chronic heart failure due to dilated (DCM; n = 7) or ischaemic cardiomyopathy (ICM; n = 9) with the stem cell mobilising cytokine granulocyte colony-stimulating factor (G-CSF; four 10-day treatment periods interrupted by treatment-free intervals of equal length). Safety and efficacy analyses were performed at regular intervals. Peak CD34+ cell counts remained constant from cycle to cycle. Cardiac side effects in ICM patients included occasional episodes of dyspnea or angina and one episode of fatal ventricular fibrillation. Nine (4 DCM, 5 ICM) of 12 patients receiving four full G-CSF cycles experienced an improvement by one New York Heart Association (NYHA) class and a statistically significant increase in six-minute walking distance. By contrast, none of 8 ICM historical controls had a change in NYHA class during a similar time period. Statistically significant changes in echocardiographic parameters were not recorded. Sequential administration of G-CSF is feasible and possibly effective in improving physical performance in patients with chronic heart failure. Patients with ICM may be at risk of increased angina and arrhythmias.

Aged↗
PubMed2002

Biventricular pacing improves quality of life and exercise tolerance in patients with heart failure and intraventricular conduction delay.

BACKGROUND: Biventricular pacing improves left ventricular dysynchrony, leading to improvement in congestive heart failure symptoms. The extent of placebo effect, the predictors of response and the long term benefits are unknown. PATIENTS AND METHODS: Forty-five patients with symptomatic congestive heart failure underwent implantation of a biventricular pacing system over a 30-month period (age 65 10 years, 37 men). Patients underwent implantation of a biventricular pacemaker or implantable defibrillator one month or longer after stabilization of congestive heart failure on maximal medical therapy, including angiotensin-converting enzyme inhibitors in 84% of patients and beta-blockers in 56% of patients. Three patients had New York Heart Association (NYHA) class II heart failure, 34 had NYHA class III and eight had NYHA class IV. Cardiomyopathy was ischemic in 31 patients, dilated in 12 and the result of other causes in two. The left ventricular ejection fraction was 19 5%. RESULTS: Implantation of the biventricular pacing system was successful in 38 of 45 patients (84%). Two patients had successful implantation with a second attempt, and one patient had an epicardial lead implant. Lead dislodgement occurred in four patients, with successful repositioning in all. During a mean follow-up of 10 7 months, the Minnesota Living with Heart Failure Questionnaire quality of life index score improved from 62 16 to 42 22 at one month (P<0.001), but subsequently returned to intermediate levels (55 26 at three months, 48 26 at six months and 56 34 at one year, P=0.50). In seven patients with deferred device activation, quality of life scores also improved by 10 15 points from baseline to one month with VDI 35 pacing, and improved a further 15 20 points with left ventricular lead activation. The mean NYHA class fell from 3.1 0.5 at baseline to 2.7 0.7 at one month (P=0.006) and remained stable thereafter (2.8 0.9 at three months, 2.8 0.9 at six months). Six patients died during follow-up, one patient had a cardiac transplantation and subsequently died, one patient had a successful cardiac transplantation and one patient underwent insertion of a left ventricular assist device. Death occurred due to progressive heart failure in five patients, sudden death occurred in one patient and a noncardiovascular cause resulted in the death of one patient. An analysis of NYHA responders (NYHA class improvement of 1 or more at last follow-up, 44% of patients) and quality of life responders (score improvement of 10 or more at last follow-up, 57% patients) did not show any difference in age, sex, heart failure etiology, QRS width, ejection fraction or baseline NYHA class. CONCLUSIONS: Biventricular pacing improves quality of life and NYHA class in patients with advanced heart failure and intraventricular conduction delay. The attenuated benefit seen over time may be related to initial placebo effect or simple dual- chamber pacing, or the natural history of the underlying disease. Identification of patients most likely to respond to biventricular pacing was not possible.

Aged↗
PubMed1991

Exercise tolerance in patients with heart failure--how should it be measured?

The exercise capability of 12 patients with heart failure was investigated by a variety of different methods before and after treatment with the vasodilator flosequinan. Two treadmill protocols were used, a modified Bruce with incremental workloads and a fixed workload protocol. On placebo, mean exercise time was greater with the Bruce protocol, 526 (64) s, than with the fixed protocol, 359 (59) s, P less than 0.005. Flosequinan increased exercise time more with the fixed protocol, so after 5 weeks' treatment exercise time was the same with both protocols; 680 (64) s with the Bruce and 673 (147) s with the fixed protocol. When the results are expressed as work, the patients achieved less with the Bruce protocol, 7.8 (1.9) kJ, than with the fixed protocol 12.5 (1.5) kJ on placebo, P less than 0.01. After flosequinan, the respective values were 14.5 (2.8) and 25.3 (5.1) kJ. Flosequinan improved corridor walk test times but there was no relationship between this and either treadmill test. Pedometer scores of customary activity were unchanged by flosequinan and were not correlated with any other exercise test. Different methods of assessing exercise capability provide different measures of patients' incapacity.

Clinical Protocols↗
PubMed1984

Effects of ipratropium bromide and fenoterol aerosols on exercise tolerance.

Twelve male patients with radiological evidence of pulmonary emphysema performed progressive exercise tests on a cycle ergometer. Ipratropium bromide (Ip) 40 micrograms, Fenoterol (Fen) 400 micrograms, their combination (Ip/Fen) and Placebo were administered from metered-dose inhalers in a double-blind crossover study to compare the effects on ventilation (VE), heart rate (fc) and oxygen uptake (VO2) at rest and at maximal and sub-maximal workloads. There were no significant differences in resting VE (p greater than 0.05) between the 4 treatment regimes. During submaximal exercise, VE at a given workload was greater after Fen containing treatment regimes than after Ip alone or placebo. There was no significant difference in the maximal workload achieved after the active treatments compared with placebo. With respect to fc and VO2, there were no differences between treatments at rest or on submaximal or maximal exercise. Fenoterol produces a mild stimulation of VE during exercise as observed with other beta-agonists, but compared with the changes in resting vital capacity, functional residual capacity and residual volume, the bronchodilator induced changes in exercise variables were relatively small.

Aged↗
PubMed2003

[Preliminary data on combined assessment of tolerance to exercise, left ventricular contractile function in ischemic heart disease patients taking bradycardic agents].

AIM: To study effects of bradicardia induced by atenolol, diltiazem and ivabradin on exercise tolerance, myocardial perfusion and left ventricular contractile function in patients with stable angina pectoris. MATERIAL AND METHODS: The trial included 7 male patients aged 57 +/- 2.6 years with coronary heart disease, stable angina of functional class II free of cardiac failure and severe arterial hypertension, with a positive and reproducible VEM test after therapy discontinuation. For 10 consecutive days with 5-day intervals, all the patients received atenolol, diltiazem, ivabradin in doses lowering heart rate at rest by 20% from the initial level. Before the treatment all the patients were studied with VEM test, perfusion synchronized single-photon emission computerized tomoscintigraphy of the myocardium (PSSPECT) at rest and exercise. On day 10 of each drug intake PSSPECT and VEM test were performed if the expected heart rate was achieved. RESULTS: Each of the studied drugs resulted in a 22-24% reduction in the heart rate at rest accompanied by a significant rise in exercise tolerance, improvement of performance and myocardial perfusion. There were no significant changes in left ventricular contractility. CONCLUSION: A 20% reduction in resting heart rate due to monotherapy with drugs having a bradicardic effect leads to positive changes in exercise tolerance and myocardial perfusion.

Atenolol↗
PubMed1985

Effects of coenzyme Q10 on exercise tolerance in chronic stable angina pectoris.

The effects of coenzyme Q10(CoQ10) on exercise performance were studied in 12 patients, average age 56 years, with stable angina pectoris. The study involved a double-blind, placebo-controlled, randomized, crossover protocol, using multistage treadmill exercise tests. CoQ10(150 mg/day in 3 daily doses) was administered orally for 4 weeks, tended to reduce anginal frequency from 5.3 +/- 4.9 to 2.5 +/- 3.3 attacks for 2 weeks and nitroglycerin consumption from 2.6 +/- 2.8 to 1.3 +/- 1.7 tablets for 2 weeks compared with patients receiving the placebo, but the reduction was not statistically significant. Exercise time increased from 345 +/- 102 seconds with placebo to 406 +/- 114 seconds during CoQ10 treatment (p less than 0.05). The time until 1 mm of ST-segment depression occurred increased from 196 +/- 76 seconds with placebo to 284 +/- 104 seconds during CoQ10 treatment (p less than 0.01). During the exercise test, ST-segment depression, heart rate and pressure-rate product at the same and at the maximal workload showed no significant difference between patients after placebo and CoQ10 administration. The average CoQ10 plasma concentration increased from 0.95 +/- 0.48 microgram/ml to 2.20 +/- 0.98 microgram/ml after CoQ10 treatment. This increase was significantly related to the increase in exercise duration (r = 0.68, p less than 0.001). Only 1 patient had a loss of appetite, but continued therapy. This study suggests that CoQ10 is a safe and promising treatment for angina pectoris.

Aged↗
PubMed1984

Sympathetic nervous system and exercise tolerance response in normotensive and hypertensive adolescents.

Comparative evaluation of isometric and dynamic exercise performance in normotensive, borderline hypertensive and hypertensive adolescents was made. Hemodynamic changes were correlated with level of adrenergic sympathetic nervous system activity as measured by plasma epinephrine and norepinephrine values. No significant intergroup differences were found with respect to isometric exercise with the exception of high peak isometric exercise heart rates and plasma epinephrine levels in the patients with significant hypertension. During dynamic treadmill testing, patients with the most marked hypertension demonstrated a statistically significantly greater tachycardia response to exercise that correlated with highest peak exercise epinephrine levels. The most hypertensive systolic dynamic exercise response was evidenced in the borderline hypertensive group in which peak exercise norepinephrine values were significantly higher than in other groups. Maximal exercise serum lactate levels were higher in hypertensive patient groups than in normotensive subjects. Altered hemodynamic response to peak dynamic exercise appears to exist in adolescents with borderline and significant hypertension and is in part mediated by altered activity of the sympathetic nervous system.

Adolescent↗
PubMed1990

Exercise tolerance in end-stage renal disease.

The cardiorespiratory and metabolic response to exercise was evaluated in children with end-stage renal failure maintained on haemodialysis. Eight patients (haemodialysis group), 4 boys and 4 girls, with a mean age of 13.4 +/- 3.6 years (range 9.4-18.6 years) and haemoglobin levels ranging from 5.3 to 7.6 g/dl and 16 healthy children (control group) performed a progressive exercise testing on a treadmill. Gas exchange was simultaneously monitored. The mean ventilatory anaerobic threshold of the haemodialysis group, expressed as a percentage of the reference values, was 59.1 +/- 18.2%, and their maximum work load (29.9 +/- 19 W) was about one fourth of that reached by the control group (113.3 +/- 51.6 W). Ventilatory anaerobic threshold values in the haemodialysis group significantly correlated with blood haemoglobin levels, but not with creatinine and parathyroid hormone concentrations. We, therefore, conclude (1) that children maintained on chronic haemodialysis have a marked reduction in aerobic working capacity and (2) that the major cause for this limitation appears to be the reduced haemoglobin concentration.

Adolescent↗
PubMed1992

The value of chest pain during the exercise tolerance test in predicting coronary artery disease.

UNLABELLED: The predictive power of 10 common exercise test parameters compared with coronary angiography was studied. Only the exercise electrocardiogram (EXECG), maximal rate pressure product (MAXRPP), and exercise chest pain (EXCP) contributed unique predictive information with the emergence of two interactions involving EXCP (EXCP.EXECG and EXCP.MAXRPP). IN CONCLUSION: (1) EXCP appears to be a more serious finding only in those higher risk individuals with either a positive EXECG or lower MAXRPP; (2) EXCP and its interactions may help discriminate between anginal and nonanginal, exertional chest pain, and (3) the contradictory results found when EXCP was allowed to interact may explain conflicting results in previous multivariate models regarding the predictive significance of EXCP.

Adult↗
PubMed1981

Exercise tolerance five years after coronary bypass surgery in relation to clinical and angiographic findings.

Exercise on a bicycle ergometer was used to assess symptom-limited working capacity (Wsl) five years after coronary bypass surgery. Ninety-six patients were evaluated with a sitting bicycle test using 10 Watt increments of work load every minute from an initial load of 10 Watt. Ninety-three per cent had less symptoms than before surgery and 32% said they had no angina. Angina was provoked at exercise in 1/31 asymptomatic patients (3%) and in 46/65 (71%) of those with residual symptoms. The Wsl of 50-250 Watt (mean 143 Watt) in a asymptomatic patients was significant higher than 30-220 Watt (mean 105 Watt) performed by patients with residual angina. In 61 patients, exercise tests were performed before, one year and five years after the operation. Average Wsl was significantly higher after one year (127; 36 Watt) than before surgery (90; 23 Watt). but declined significantly until the five-year evaluation (113; 37 Watt). After one year 82% had a higher Wsl than prior to operation compared to 69% five years after surgery. Angiography five years after surgery revealed that 60/76 subjects (79%) had all grafts patent and 16/76 (21%) one or more grafts occluded. In spite of one or more grafts occluded. 2/16 patients (13%) were asymptomatic, whereas 25/60 (42%) with all grafts patent were free from symptoms. Average Wsl was significantly higher in patient with all grafts patent (130; 44 Watt) compared to patients with one or more grafts occluded (102; 33 Watt). It is concluded that although subjective improvement after coronary bypass surgery persisted in about 90% of the patients for five years, bicycle exercise tests show a significant decline of Wsl after the first year, but five years after surgery was still better than before the operation.

Adult↗
PubMed1976

Exercise tolerance at 4 and 6 ATA.

Seven normal male subjects performed 5-min bicycle exercise ranging from 50-100% maximum oxygen uptake at 4 ATA and three were also studied at 6 ATA. At all pressures, the subjects breathed 0.2 ATA O2 plus nitrogen. All subjects were able to perform maximum work at all pressures. No pressure-dependent variations in heart rate, O2 uptake, or CO2 output were noted. At both 4 and 6 ATA, ventilation was decreased at exercise levels greater than 80% maximum O2 uptake. The magnitude of the decrease was not great, however, and signified only minor CO2 retention. In some instances exercise ventilation closely approached the 15-S maximum breathing capacity and these subjects noted severe dyspnea, possibly due to dynamic compression of large airways. In three subjects, respiratory frequency was measured as well as minute ventilation; this relationship did not change with depth. Subjects performing heavy exercise at 6 ATA noted disturbances of consciousness, presumably due to N2 narcosis.

Adaptation, Physiological↗
PubMed1985

Measurement of exercise tolerance in patients with rheumatoid arthritis and osteoarthritis.

We evaluated the effect of strenuous aerobic exercise on joint symptoms and compared the functional capacity and muscle strength among patients with rheumatoid arthritis (RA) and osteoarthritis (OA), and very sedentary matched controls. Strenuous ergometer exercise did not exacerbate joint symptoms in these patients. Isotonic leg extension and flexion as well as grip strength were diminished in the RA and OA subjects compared to controls (p less than 0.05). All subjects displayed low maximum oxygen consumption indicating reduced functional capacity. Acute bouts of strenuous exercise performed on bicycle ergometer do not appear harmful to the nonacute arthritis patient.

Adult↗