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PubMedDate not supplied

Effect of intravenous verapamil on exercise tolerance and left ventricular function in patients with severe exertional angina pectoris.

The hemodynamic effects of 0.1 mg/kg verapamil given intravenously to 7 patients with angina pectoris were studied at rest and during exercise in the supine position. Cardiac output was measured with the thermodilution technique, which permitted measurements every 30 sec during exercise. Maximal exercise tolerance increased significantly after verapamil. Verapamil had no effect on heart rate at rest, but significantly increased it at the end of the exercise. Left ventricular systolic pressure was reduced by verapamil at rest and during submaximal exercise. Left ventricular end-diastolic pressure was not influenced by verapamil at rest, but was significantly lowered during submaximal exercise. Stroke work index and left ventricular power index were not influenced by verapamil. Rate pressure product was lowered by verapamil during submaximal exercise but had a tendency to be increased at the breaking point. Verapamil had no negative inotropic effect as judged from the left ventricular function curve. It is suggested that the beneficial effect of verapamil relates mainly to a reduction of left ventricular pre- and after-load. The slightly higher rate pressure product after verapamil may also suggest a slight improvement of myocardial perfusion.

Adult↗
PubMed2003

Aortic distensibility independently affects exercise tolerance in patients with dilated cardiomyopathy.

BACKGROUND: Peak exercise oxygen consumption (VO2) is crucial for the prognostic stratification of patients with congestive heart failure, but its hemodynamic determinants are still not completely understood. Aortic wall elasticity modulates left ventricular function and coronary blood flow. Whether an increased aortic pulse-wave velocity (PWV), a known marker of arterial stiffness, may predict peak VO2 in patients with dilated cardiomyopathy (DCM) has to be clarified. METHODS AND RESULTS: A total of 78 patients with clinical diagnosis of DCM (aged 62+/-11 years; female 29%; mean ejection fraction 34+/-9%) were selected. All patients underwent a complete echocardiographic-Doppler evaluation. Aortic PWV was measured by Doppler ultrasonography immediately before the exercise. A bicycle exercise test with expiratory gas exchange monitoring was performed to determine VO2 . Plasma concentration of the amino-terminal propeptide of type III procollagen (PIIINP), a marker of extracellular matrix turnover, was determined. Mean PWV was 5.7+/-2.2 m/s, and VO2 was 16.5+/-4.5 mL x kg(-1) x min(-1). The hemodynamic variables correlated with VO2 were PWV (r=-0.39, P=0.0007) and stroke volume (r=0.38, P=0.002). In a multivariate analysis, PWV (P=0.04) and stroke volume (P=0.05) were independently correlated with VO2 , accounting for 34% of its variance. PIIINP levels correlated with PWV (r=0.35, P=0.002) and a more restrictive diastolic filling pattern (r=0.40, P=0.02). CONCLUSIONS: Increased aortic stiffness measured by PWV is an independent predictor of peak VO2 and could partially explain exercise intolerance in patients with DCM.

Aorta↗
PubMed1992

The effect of transdermal nitroglycerin on exercise tolerance in relation to patch application time--a meta-analysis.

Disagreeing results have been reported in the many studies on continuous treatment with nitroglycerin patches. The effects on exercise tolerance are partly studied at the end of a 24-hour application period, and partly examined only a few hours after patch renewal. The present meta-analysis estimates the overall efficacy of nitroglycerin patches in trials with and without concomitant antianginal therapy, and investigates if the treatment effect depends on the patch application time. A computed search (MEDLINE) identified 110 publications, of which 17 trials on nitrate patch monotherapy and six trials on combined therapy satisfied the inclusion criteria. Data on "exercise duration" and "ST-segment depression" were converted to a standardized treatment effect size d, and pooled to an overall treatment effect size d+. In tests 2-5 hours after patch renewal, moderate but significant effects of nitrate monotherapy were observed; d+ was 1.20 with regard to "ST-segment depression" and 0.39 with regard to "exercise duration" (both p < 0.0001). In contrast, 24 hours after patch application, the values for d+ were 0.09 (not significant) and 0.36 (p < 0.01), respectively. When adding the results from the six trials on combined therapy, d+ with regard to "exercise duration" was reduced to 0.28 (p < 0.0001) 2-5 hours after renewal and to 0.17 (p = 0.04) after 24 hours. Thus, the efficacy of continuous nitroglycerin patch treatment is moderate but evident during exercise tests 2-5 hours after patch renewal; however, it is reduced after 24 hours of patch application.

Administration, Cutaneous↗
PubMed1979

Effect of plasma free fatty acid lowering on exercise tolerance and ST segment depression in patients with angina pectoris.

The effect of a single oral dose of a plasma FFA-lowering drug (5-(3-pyridyl) tetrazole), which does not act by conversion into nicotinic acid, on exercise tolerance and ECG reaction was studied on a double-blind basis in 15 men with stable angina pectoris. Exercise was performed on a bicycle ergometer in the sitting position with a load increase of 10 W/min. In addition to ECG, time to onset of chest pains and to termination of exercise because of strong chest pains was recorded. 5-(3-pyridyl) tetrazole decreased plasma FFA during exercise from 523 to 299 mumol/l. It reduced significantly the ST depression at corresponding work loads and permitted the patients to exercise 0.6 min longer, corresponding to a 7% higher work load, before the onset of chest pain. However, absolute exercise time was not significantly increased. The most probable explanation of the improved performance is a decreased lipid and increased carbohydrate oxidation by the ischemic heart, although a contribution may have come from hemodynamic effects of the drug, unrelated to effects on myocardial metabolism but perhaps involving heart rate and BP. The lack of a significant effect on performance time may have been due to general fatigue.

Administration, Oral↗
PubMed1986

Predictive value of the exercise tolerance test for mortality in North American men: the Lipid Research Clinics Mortality Follow-up Study.

More than 3600 white men, from 30 to 79 years old and without a history of myocardial infarction, underwent submaximal treadmill exercise tolerance tests as part of their baseline evaluation for the Lipid Research Clinics Mortality Follow-up Study. The exercise test was conducted according to a common protocol and coded centrally; depression of the ST segment by at least 1 mm (visual coding) and/or 10 microV-sec (ST integral, computer coding) signified a positive test. Concurrent measurements of age, blood pressure, history of cigarette smoking, and plasma levels of lipids, lipoproteins, and glucose, as well as other coronary risk factors, were obtained. Cumulative mortality from cardiovascular disease was 11.9% (22/185) over 8.1 years mean follow-up among men with a positive exercise test vs 1.2% (36/2993) over 8.6 years mean follow-up among men with a negative test. Three-quarters (43) of these deaths were due to coronary heart disease. The relative risk for cardiovascular mortality associated with a positive exercise test was 9.3 before and 4.6 after age adjustment. Cardiovascular mortality rates were especially elevated (relative risk 15.6 before and 5.1 after age adjustment) among the 82 men whose exercise tests were adjusted "strongly" positive based on degree and timing of the ischemic electrocardiographic response. A positive exercise test was also moderately associated with noncardiovascular mortality; the relative risk for all-cause mortality was 7.2 before and 3.4 after age adjustment. The relative risk for cardiovascular mortality associated with a positive exercise test was not appreciably altered by covariance adjustment for known coronary risk factors other than age. A positive exercise test was a stronger predictor of cardiovascular death than were high plasma levels of low-density lipoprotein cholesterol, low plasma levels of high-density lipoprotein cholesterol, smoking, hyperglycemia, or hypertension. Its impact on risk of cardiovascular death was equivalent to that of a 17.4 year increment in age.

Adult↗
PubMed1987

Effects of chronic administration of codeine and promethazine on breathlessness and exercise tolerance in patients with chronic airflow obstruction.

It has been reported that short-term treatment with relatively high doses of opiates or promethazine causes improvements in dyspnoea and exercise tolerance in patients with chronic airflow obstruction (CAO). This study was designed to determine whether initial benefits were sustained during chronic administration of codeine or promethazine and to compare the two drugs in terms of their efficacy and possible mechanisms of action. Eleven patients with stable CAO were entered into a double-blind, randomized cross-over trial in which codeine (30 mg four times daily) or promethazine (25 mg four times daily) were orally administered for 1-month periods. Treatment effects were assessed by spirometry, arterial blood gases, 12-minute walk distance and subjective dyspnoea ratings. A statistically significant increase from the baseline in mean arterial PCO2 at at 24 hours (P less than 0.01) and at 1 month (P less than 0.05) occurred with codeine administration. There was no significant change from baseline for any other measurement with either drug, and no differences were detected between the two treatment arms. Four of the eleven patients did not complete the study; three of the four experienced worsening of their CAO requiring hospitalization (two while receiving codeine, one while receiving promethazine). We conclude that chronic treatment with either codeine or promethazine provides uncertain benefits to patients with CAO which may not outweigh potential risks.

Aged↗
PubMed1984

Effect of Corwin (ICI 118587) on resting and exercise heart rate and exercise tolerance in digitalised patients with chronic atrial fibrillation.

The effect of Corwin, a new oral beta, partial agonist, on the ventricular response to atrial fibrillation was studied in digitalised patients during 24 hour ambulatory electrocardiography and during exercise on a treadmill in a double blind placebo controlled crossover trial. Corwin reduced the maximum heart rate during exercise from 162(16) beats/min to 120(9) beats/min and reduced the peak heart rate during ambulatory electrocardiography from 113(11) to 90(6) beats/min consistent with a beta adrenoreceptor antagonist action at higher levels of sympathetic nervous system activity. Minimum heart rate during ambulatory electrocardiography was increased from 62(5) to 70(5) beats/min indicating that at lower levels of sympathetic activity the drug acts as a beta agonist. The drug increased exercise tolerance significantly. Serum digoxin concentrations were not affected by the drug. Thus Corwin appears to be effective in stabilising heart rate during atrial fibrillation both at rest and during exercise in digitalised patients.

Adrenergic beta-Agonists↗
PubMed1992

A double-blind study of submaximal exercise tolerance and variation in paced rate in atrial synchronous compared to activity sensor modulated ventricular pacing.

To assess the variation in paced rate during everyday activity and the importance of atrioventricular synchronization (AV synchrony) for submaximal exercise tolerance, atrial synchronous (DDD) and activity rate modulated ventricular (VVI,R) pacing were compared in 17 patients with high degree AV block. The patients were randomly assigned to either mode and evaluated by treadmill exercise to moderate exertion and by 24-hour Holter monitoring after 2 months in the DDD and VVI,R modes, respectively. At the end of the study, the patients were programmed to the pacing mode corresponding to the preferred study period. During the treadmill test, the mean exercise time to submaximal exertion (Borg 5/10), exertion ratings and respiratory rate did not differ between pacing modes despite a significantly lower ventricular rate in the VVI,R mode. The atrial rate during VVI,R pacing was significantly higher than the ventricular rate, but did not differ from the ventricular rate during DDD pacing. There was a diurnal variation in paced rate in both pacing modes. Paced ventricular rate was, however, higher and variation in paced rate greater in DDD compared to VVI,R pacing. Nine patients preferred the DDD mode, three patients preferred the VVI,R mode, while five subjects did not express any preference. The results from this study indicate that the variation in paced rate during activity sensor-driven VVI,R pacing does not match that during DDD pacing neither during everyday activities nor during submaximal treadmill exercise. Nevertheless, no differences in exercise time, Borg ratings, and respiratory rate during submaximal exercise were found. Thus, for most patients with high degree AV block, DDD and VVI,R pacing seem equally satisfactory for submaximal exercise.

Cardiac Pacing, Artificial↗
PubMed1995

Short-term effects of captopril on exercise tolerance in patients with chronic stable angina pectoris and normal left ventricular function.

A double-blind, placebo-controlled, crossover study was carried out to evaluate the short-term effects of captopril on exercise tolerance in 18 normotensive patients with chronic stable angina pectoris and normal left ventricular function. Captopril 25 mg (or placebo) was given twice, i.e. in the evening (10 p.m.) and the following morning (8 a.m.), prior to a maximal symptom-limited bicycle exercise test (11 a.m.). Captopril reduced the systolic and diastolic blood pressures at rest (p < 0.01) without causing any reflex tachycardia. The time to onset of S-T depression was prolonged (p < 0.05), and the maximal S-T depression was reduced (p < 0.02). No differences were found between captopril and placebo in total exercise duration or time to onset of angina. The effects of captopril on exercise-induced ischemia were demonstrated most clearly in patients who responded with a greater than 10 mm Hg fall in the resting systolic blood pressure. In conclusion, this study suggests that captopril has anti-ischemic properties, which may be of importance in the treatment of patients with chronic stable angina and normal left ventricular function. These beneficial effects probably relate to a reduction in afterload and myocardial wall stress and therefore a reduction in myocardial oxygen demand.

Adult↗
PubMed1987

The effects of verapamil and propranolol on exercise tolerance in hypertensive patients.

In a single-blind, placebo-controlled crossover study the effects of verapamil (450 +/- 30 mg/day) and propranolol (160 +/- 20 mg/day) on endurance time during submaximal exercise were compared in eight patients with essential hypertension. The drugs were given in randomized order. Each active drug period was preceded by a placebo phase. Endurance tests were performed during both placebo periods and treatment with verapamil and propranolol by bicycle ergometry. Both drugs were equally effective in decreasing resting blood pressure. Verapamil and propranolol reduced exercise heart rate, the effect of propranolol being more pronounced. With placebo, endurance time during exercise was 57 +/- 11 minutes; with propranolol it was 32 +/- 7 minutes (P less than 0.05). Verapamil had no influence on endurance time. The study demonstrates that in contrast to propranolol, verapamil has no influence on exercise tolerance during submaximal work in patients with hypertension.

Adult↗
PubMed1983

Effects of molsidomine on exercise tolerance in patients with coronary heart disease.

We performed a double-blind crossover study with molsidomine in 10 patients with coronary heart disease. A single dose of molsidomine and placebo were given sublingually 1 hour before an exercise tolerance test. Molsidomine significantly reduced systolic blood pressure at rest and at all work-loads. There was also a significant reduction in electrocardiographic ST-segment depression at submaximal exercise. At maximal exercise the drug significantly increased symptom-limited oxygen consumption and total mechanical work. Molsidomine could prove useful in the treatment of angina pectoris. It has no adverse effects on pulmonary function.

Aged↗
PubMed1984

Effect on exercise tolerance and pharmacokinetics of conventional and sustained release preparations of propranolol in patients with angina pectoris--a double-blind cross-over study.

Ten patients with effort angina were studied in a randomized double-blind cross-over trial in order to investigate the effect of sustained release propranolol (LA) and conventional propranolol (Prop) formulations on exercise tolerance. LA was given once daily and Prop three times daily. Treadmill exercise tests were performed using the Bruce protocol and the plasma propranolol levels were measured. The following results were obtained: LA proved to have an anti-anginal effect similar to Prop. No adverse reactions were observed after administration of either of the drugs. Similar suppressive effect of the heart rate, blood pressure and double product at rest and on exercise was seen after LA and Prop while the exercise capacity was increased. The plasma level of propranolol was higher at 2 hours after Prop than LA administration, but there was no difference between LA and Prop at 4 and 24 hours after administration. The plasma propranolol level at 4 hours after LA correlated with the percent reduction in exercise heart rate and with the percent reduction in the double product. Our study suggested that once-a-day administration of LA could improve patients' compliance and adds another choice to the list of clinically useful beta-blockers for the treatment of angina pectoris on effort.

Aged↗
PubMed1982

Effect of change in P50 on exercise tolerance at high altitude: a theoretical study.

Acclimatization to altitude often results in a rightward shift of the O2 dissociation curve (ODC). However, a left-shifted ODC is reported to increase exercise tolerance in humans at medium altitude and increase survival in rats breathing hypoxic gas mixtures. We examined this paradox using a computer model of pulmonary gas exchange. A Bohr integration procedure allowed for alveolar-capillary diffusion. When diffusion equilibration was complete, mixed venous (PVO2) and arterial PO2 fell as O2 consumption (VO2) was increased, but PVO2 approached a plateau. Under these conditions a right-shifted ODC is advantageous (higher PVO2) at all but very high altitudes. However, diffusion limitation of O2 transfer may occur at any altitude if VO2 is increased sufficiently. If this occurs, a left-shifted ODC results in higher calculated VO2max (compared with the standard ODC). Further, diffusion limitation always occurs at a lower VO2 with a right-shifted ODC than with a left-shifted ODC. We conclude that whether a leftward or rightward shift in the ODC is advantageous to gas exchange at altitude depends on the presence or absence of diffusion limitation.

Altitude↗
PubMed1986

Exercise tolerance and compensatory sympathetic tone during beta-blockade after myocardial infarction.

Using chronically instrumented dogs with a healed anterior wall myocardial infarction, we have assessed the effect of acute beta-adrenergic blockade on exercise tolerance, left ventricular (LV) performance, and myocardial VO2. Mongrel dogs were instrumented with Doppler flow probes around the left circumflex coronary artery, LV pressure cells, epicardial ECG electrodes, and left atrial and coronary sinus catheters. Myocardial infarction was produced by ligation of the left anterior descending coronary artery at time of instrumentation (approximately 20% LV mass). After a 1-month recovery period, dogs were subjected to two identical submaximal graded exercise tests on a treadmill on separate days, once without (control) and once with (propranolol, 1 mg X kg-1, i.v.) acute beta-adrenergic blockade. Heart rate, LV pressure, dP/dt max, left circumflex blood flow velocity, and myocardial VO2 index were measured at each stage of the graded exercise test. All variables were significantly reduced from control during beta-block in exercise. beta-Adrenergic blockade in the presence of a 1-month-old anterior wall myocardial infarction did not compromise exercise capacity during submaximal exercise.

Adrenergic beta-Antagonists↗
PubMedDate not supplied

Aminophylline, respiratory muscle strength and exercise tolerance in chronic obstructive airway disease.

Fourteen patients with chronic obstructive airway disease participated in a randomized, double-blind, placebo controlled, cross-over study to assess the effect of acutely administered aminophylline on respiratory muscle strength and exercise tolerance. An increase in the distance walked in 6 min occurred following aminophylline (p less than 0.01). There was no improvement in respiratory muscle strength, assessed by maximal static mouth pressures, and no increase in maximal ventilation or oxygen uptake during a progressive exercise test. The ventilatory response to inhaled CO2 was increased (p less than 0.02), suggesting a central stimulatory effect of aminophylline. The mean increase in walking distance was 5.7%. In most cases, the change was small and unlikely to be of practical benefit.

Aminophylline↗
PubMedDate not supplied

The treadmill exercise-tolerance test is useful for the prediction and prevention of ischemic coronary events in elderly diabetics.

BACKGROUND: Approximately 80% of cases of ischemic heart disease (IHD) occur in patients with nonstenotic coronary arteries, and few studies have systematically assessed exercise testing (TMT) as a predictor of risk in the elderly. METHODS: TMT was carried out using a protocol for the independent and active elderly (n=176). After 4.1+/-0.5 years follow-up, logistic regression analysis was performed for each coronary risk factor such as diabetes mellitus (DM) and hypercholesterolemia (HC). According to the results, patients were divided into Gp HC, hypercholesterolemic patients; Gp DM, diabetics; Gp HC+DM, hypercholesterolemic diabetics; and Gp C, nonhyperlipidemic and nondiabetics. Sensitivity and specificity of TMT for IHD (significant stenosis or acute coronary syndrome) were analyzed. RESULTS: Odds ratios for each risk factors are as follows: DM, 4.167; HC, 4.485; and DM+HC, 8.652. Notably, TMT was 17.59. Age was a significant risk, but hypertension was not. Positive ischemic signs in TMT were observed in 52.7%, 28.6%, 33.3%, and 16.3% in the Gp HC+DM, HC, DM, and C groups, respectively. Only three participants complained of chest pain during the TMT. Significant stenosis was observed in 75.0%, 71.4%, 69.2%, and 60.0% of coronary angiography (CAG)-receiving patients of Gp HC, DM, HC+DM, and C. During the observation term, acute coronary syndromes occurred in 4.7%, 3.3%, 5.5%, and 0% of patients in the Gp HC, DM, HC+DM, and C groups, respectively. The sensitivity of TMT for IHD was higher than 66.7% and specificity was higher than 94.1% in each group. CONCLUSION: An exercise tolerance test in the elderly, especially for diabetics and hypercholesterolemic patients, is useful for the diagnosis of IHD.

Age Factors↗
PubMed1990

Ventilatory control, exercise tolerance and respiratory dysfunction in Thai COPD patients.

This study was designed to investigate a group of Thai COPD patients for their respiratory centre sensitivity while breathing room-air and during CO2 rebreathing, and tests to determine exercise tolerance and degrees of respiratory dysfunction. Results in 56 patients as compared with 45 age-matched healthy subjects disclosed comparable data between both subject groups, with the single exception that one-third (35.7%) of the patients experienced stronger ventilatory drive while breathing room-air and a lower musculo-ventilation transfer index during room-air breathing as well as CO2 rebreathing. According to the base-line dyspnoea index, the majority of Thai COPD patients in this study suffered from a very severe respiratory dysfunction, which correlated well with results of their basic physiologic tests.

Aged↗