SEARCH · PubMed Health

Results for “Exercise Tolerance”

Explore indexed PubMed citations for clinical trials, systematic reviews and public health research. Read source abstracts and follow each citation to its original PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 235 records · Page 13Linked to original sources

PubMed1987

Failure of propranolol to improve exercise tolerance in patients with mitral stenosis in sinus rhythm.

Propranolol reduces left atrial pressure at rest and during exercise in patients with mitral stenosis by lowering cardiac output and heart rate. Ten patients (aged 19-56) with moderate to severe isolated mitral stenosis were studied to determine whether propranolol increased their exercise tolerance. All were in sinus rhythm and free of left or right ventricular failure. Patients were trained in an individually graded bicycle or treadmill exercise protocol that provoked a reproducible degree of near maximal dyspnoea during the second three minute stage of exercise. Propranolol (80 mg or 120 mg) or matching placebo in two or three divided daily doses was given for one week in random double blind fashion. Exercise testing and questioning about subjective clinical response were carried out at the end of each week by an investigator who was unaware of the patient's heart rate. During propranolol treatment the heart rate was 19 beats/minute slower at rest and 38 beats/minute slower at peak exercise, but there was no change in mean exercise time to dyspnoea (274 s during propranolol vs 283 s during placebo). Four patients felt worse during the propranolol week, one patient felt better during the propranolol week, and five patients felt no difference between the two weeks. Propranolol did not improve objective or subjective exercise tolerance in patients with isolated mitral stenosis in sinus rhythm.

Adult↗

PubMed1993

Lack of effect of nitrates on exercise tolerance in patients with mild to moderate heart failure caused by coronary disease already treated with captopril.

OBJECTIVE: To test the hypothesis that the addition of nitrates improves exercise tolerance in patients with heart failure caused by coronary artery disease already treated with an angiotensin converting enzyme inhibitor and diuretics. DESIGN: Randomised, double blind, placebo controlled, 16 week treatment periods. SETTING: Outpatient clinic at a university hospital. PATIENTS: 54 patients with previous myocardial infarction, symptoms of mild to moderate heart failure, left ventricular ejection fraction below 40%, no exercise-induced angina or electrocardiographic signs of ischaemia. Four patients in the nitrate group (n = 24) and one patient of the placebo group (n = 25) were withdrawn from the study. INTERVENTION: After the patients had been on constant doses of captopril and diuretics for at least 2 weeks, they were randomised to receive a target dose of 40 mg isosorbide dinitrate twice daily or placebo in addition to the continuation of captopril and diuretics. MEASUREMENTS: Bicycle exercise tests with measurement of gas exchange were carried out before randomisation and after 1, 6, 12, and 16 weeks of the double blind treatment. The change in peak oxygen uptake from control to week 16 was prospectively defined as the main outcome measure. RESULTS: The increase in peak oxygen uptake from before randomisation tended to be greater in the placebo group (before randomisation 17.4 (3.4) ml/min/kg) than in the nitrate group (before randomisation 17.1 (3.5) ml/min/kg) after 12 weeks (mean increase 1.1 (2.7) v 0.0 (2.7) ml/min/kg, p < 0.12) and 16 weeks (1.7 (3.0) v 0.3 (2.6) ml/min/kg, p < 0.14) of treatment. CONCLUSION: The addition of nitrates to a baseline treatment consisting of captopril and diuretics did not improve exercise tolerance.

Adult↗

PubMed1991

Exercise tolerance of end-stage renal disease patients.

The purpose of this study was to evaluate the exercise tolerance of end-stage renal disease patients, and to examine pulmonary function and blood lactate as its possible limiting factors. Ten end-stage renal disease patients (age 30 +/- 11) were tested at rest and in a subsequent graded treadmill test to exhaustion. Velocity was 4.8 km/h and the grade was incremented by 2.5% every 4 min. One minute of rest, used for blood sampling, separated successive stages. Pulmonary functions (FVC, FEV1) at rest were both 76% of predicted. Resting heart rate, systolic and diastolic blood pressures, and ventilatory equivalent values were higher than normal. At peak exercise, heart rate, oxygen uptake, oxygen pulse and blood lactic acid were lower than normally predicted for maximal exercise, while ventilatory equivalent and diastolic blood pressure were higher. Only six patients reached blood lactate levels beyond 4 mM.l-1 (onset of blood lactic acid), at which point they utilized 88 +/- 5% of their respective peak Vo2. The results suggest that the low exercise tolerance demonstrated in end-stage renal disease patients is not limited by the somewhat compromised pulmonary capacity or by excessive blood lactate levels.

Adult↗

PubMed1991

Acute effects on exercise tolerance of felodipine and diltiazem, alone and in combination, in stable effort angina.

The acute effects on exercise tolerance and electrocardiographic ischaemia of felodipine and diltiazem, alone or in combination, were investigated in 12 patients with documented stable effort-induced angina pectoris. After being withdrawn from their previous antianginal treatments, patients received a single oral dose of felodipine 10 mg, diltiazem 60 mg, their combination or placebo on four different days, according to a double-blind, 4 x 4 latin-square design. Exercise time to ischaemic threshold (ST-segment depression = 1 mm) and to peak exercise was significantly prolonged by the felodipine-diltiazem combination (492 and 504 s, respectively) against placebo (301 and 370 s, both P less than 0.01), felodipine alone (381 and 428 s, both P less than 0.01) and diltiazem alone (367 and 422 s, both P less than 0.01). The effects on total work followed a similar pattern. In comparison with placebo, the administration of felodipine and diltiazem alone significantly increased exercise duration as well as total work to ischaemic threshold and to peak exercise, with no differences between the two drugs. Systolic blood pressure during exercise was not affected by any of the treatments. However, in comparison with both placebo and diltiazem, the combination induced an increase (P less than 0.01) in heart rate during exercise. One patient suffered from symptomatic hypotension with the combination, and another had sinus tachycardia after felodipine. In conclusion, the acute concomitant administration of felodipine and diltiazem in patients with stable effort angina induces a marked improvement in exercise tolerance in comparison with placebo, felodipine alone and diltiazem alone. However, the benefit/risk profile of such a combination requires further, long-term investigation.

Angina Pectoris↗

PubMed1986

The effect of isosorbide-5-mononitrate (5-ISMN) Durules on exercise tolerance in patients with exertional angina pectoris. A placebo controlled study.

Twenty-four patients with stable exercise-induced angina pectoris entered a double-blind cross-over study. Isosorbide-5-mononitrate (5-ISMN) 60 mg in a controlled release formulation (Durules) given once daily was compared with identical placebo. The exercise tolerance was determined by bicycle ergometry before and 3 h after a single dose of 5-ISMN and following one week's treatment with 5-ISMN and placebo. Nineteen patients completed the study. Exercise tolerance until the onset of chest pain and until 1 mm ST segment depression increased significantly 3 h after dose. The same increase was seen both after a single dose and the same dose under steady-state conditions. No increase was seen with placebo. The heart rate and systolic blood pressure reactions in the standing position were less pronounced 3 h after dose in steady-state than after a single dose of 5-ISMN. Headache was the only bothersome side-effect reported. The study demonstrates that 60 mg 5-ISMN in a Durules formulation given once daily has a significant anti-anginal effect and that tolerance does not develop.

Adult↗

PubMed2002

Exercise tolerance in carnitine palmitoyltransferase II deficiency with IV and oral glucose.

BACKGROUND: Patients with carnitine palmitoyltransferase II (CPT II) deficiency often experience muscle pain and myoglobinuria during prolonged exercise because of impaired oxidation of long-chain fatty acids. OBJECTIVE: To investigate whether IV or oral glucose can improve exercise tolerance in CPT II deficiency. METHODS: Five patients with CPT II deficiency and healthy matched volunteers were investigated on a cycle ergometer at a constant workload of 60% of VO(2max). Perceived exertion, heart rate, and venous plasma glucose and insulin levels were monitored. The study was randomized, placebo controlled, single blind, and crossover. Glucose and placebo were administered both orally and IV in patients and IV in healthy subjects. RESULTS: In patients with CPT II, exercise duration was prolonged by 28 +/- 8% (p = 0.02), and perceived exertion (p = 0.05) and heart rate (p = 0.09) were lowered by glucose infusion. In contrast, IV glucose resulted in higher heart rate during exercise in healthy subjects. Oral glucose and placebo resulted in the same exercise duration, perceived exertion, and heart rate in patients. Plasma glucose and insulin were consistently elevated during exercise by oral and IV glucose vs placebo, but plasma glucose was higher and insulin lower in IV vs oral glucose studies in patients (p = 0.02). CONCLUSION: Exercise tolerance is markedly improved by a glucose infusion in patients with CPT II deficiency, but because of lower glucose availability and higher insulin levels that inhibit muscle glycogenolysis, the patients cannot achieve this effect themselves by oral glucose ingestion.

Administration, Oral↗

PubMed2004

Chronic heart failure. The relationship between increased activity of skeletal muscle ergoreceptors and reduced exercise tolerance.

BACKGROUND: In chronic heart failure (CHF), skeletal muscle abnormalities may lead to the overactivation of ergoreceptors which in turn may cause sympathetic overactivation and increased ventilatory response to exercise. AIM: To assess ergoreceptor reflex response to exercise and to evaluate whether ergoreceptor overactivity is related to the progression of CHF. METHODS: In 69 patients with CHF (66 males, mean age 62.7+/-11.6 years, NYHA class I/II/III/IV - 11/32/24/2 patients, respectively) and 24 controls without CHF (22 males, mean age 59+/-4.6 years) the ergoreflex contribution to the ventilatory and haemodynamic responses to exercise was evaluated. Moreover, in 13 patients with CHF, reproducibility of the measurements was assessed by repeating the test 1 to 7 days later. RESULTS: Enhanced ergoreflex effects on ventilation (1.9+/-1.6 vs 0.14+/-0.7 l/min, p<0.05) and systolic blood pressure (19.2+/-14.9 vs 6.1+/-5.9 mmHg, p<0.05) were found in patients with CHF compared with control subjects. Ergoreceptor overactivity was associated with a worse symptomatic state (NYHA class I vs II vs III, IV: 0.9 vs 1.5 vs 2.9 l/min, p<0.05) and lower exercise tolerance (peak V0(2): r=-0.51, p<0.0001; VE/VC0(2): r=0.50, p<0.0001). The mean values of the ergoreceptor reflex did not differ significantly between the two tests (t=1.5, p=0.14; variability coefficient = 21.5%). CONCLUSIONS: In CHF, overactivation of the ergoreflex is associated with the progression of the syndrome and may be responsible for reduced exercise tolerance. Reproducibility of ergoreflex measurements is satisfactory.

Aged↗

PubMed1992

[Evaluation of the correlation with preoperative left ventricular end-systolic volume index and postoperative exercise tolerance in the patient with aortic regurgitation].

Twenty-three male patients (49 +/- 11 years old) undergoing aortic valve replacement (AVR) for aortic regurgitation received the exercise tolerance test using bicycle ergometer at more than one year after AVR. Preoperative left ventricular end-systolic volume index (LVESVI) significantly correlated with tolerance time, peak VO2, anaerobic threshold (AT) during the exercise, and with serum noradrenaline (NAd) levels at rest. Then patients were divided into two groups: those with preoperative LVESVI < or = 70 ml/M2 (13 patients, group A), and those with LVESVI > 70 ml/M2 (10 patients, group B). All patient in group A achieved more than 75 W of the exercise, however only one in group B achieved this level. The increase of VO2 in group B with an increasing exercise was significantly suppressed compared to group A, and then, the peak VO2 levels in group B were significantly lower than in group A (A: 20.9 +/- 3.7, B: 11.4 +/- 3.9 ml/kg/min). In addition group B showed a less increase of AT levels (A: 10.6 +/- 2.9, B: 6.8 +/- 2.3 ml/kg/min). In contrast, serum lactate and NAd levels in group B increased significantly at 50 W of the exercise compared to group A (A: 12.5 +/- 3.7, 332.3 +/- 104.2; B: 17.5 +/- 5.7 mg/dl, 746.7 +/- 324.3 pg/ml, respectively) though a significant difference of NAd levels before the exercise was observed between the both groups (A: 173.7 +/- 34.2, B: 329.0 +/- 132.1). In conclusion, group A showed a better exercise tolerance physiologically and biochemically compared to group B.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗

PubMed1993

The acute response of left ventricular filling dynamics to intravenous verapamil predicts the changes in exercise tolerance after oral verapamil therapy in patients with hypertrophic cardiomyopathy.

We studied the correlation between changes in left ventricular filling dynamics induced by acute intravenous administration of verapamil and the changes in exercise tolerance induced by oral administration of the agent in 30 patients with hypertrophic cardiomyopathy. Diastolic cardiac function was measured by means of a nuclear stethoscope before and 10 min after intravenous administration of verapamil, 0.15 mg.kg-1 over 2 min. Treadmill exercise tests using a modified Bruce protocol were performed before the initiation of oral verapamil treatment and after 4 weeks of oral therapy at a dose of 320-360 mg.day-1 (mean +/- SD 332 +/- 17 mg.day-1). Peak filling rate (PFR) increased in 21 patients, 18 of whom (86%) also had an increase in exercise duration, PFR showed no increase in nine patients, eight of whom (89%) had no change in exercise duration (sensitivity 95%, specificity 73%, predictive value of the positive result 86%, predictive value of the negative result 89%). Acute changes in time from the beginning of rapid filling to PFR (t-PFR) and in left ventricular end-diastolic volume (EDV) were less useful in predicting improvement in exercise tolerance. In 19 patients the changes in PFR and EDV paralleled. Twelve of the 13 patients (92%) with an increase in both parameters also had an increase in exercise duration, whereas all six in whom these parameters were reduced showed no increase in exercise duration (sensitivity 100%, specificity 86%, predictive value of positive results 92%, and predictive value of negative results 100%).(ABSTRACT TRUNCATED AT 250 WORDS)

Administration, Oral↗

PubMed2003

The angiotensin converting enzyme inhibitor trandolapril has neutral effect on exercise tolerance or functional class in patients with myocardial infarction and reduced left ventricular systolic function.

AIMS: To study the effect of angiotensin-converting enzyme (ACE) inhibitor trandolapril on exercise tolerance time (ETT) and New York Heart Association (NYHA) classification in patients with reduced left ventricular systolic dysfunction (LVSD) after acute myocardial infarction (AMI). METHODS AND RESULTS: The TRAndolapril Cardiac Evaluation (TRACE) was a randomized controlled study designed to evaluate the effect of trandolapril on mortality in 1749 consecutive Danish patients with LVSD after AMI. NYHA class was recorded every 3 months in all patients. In a prospective sub-study, 254 patients underwent exercise tolerance tests at 1, 3 and 12 months. The two treatment arms showed equal improvement in NYHA class both in the entire and exclusively symptomatic population over 4 years of follow-up (P=ns). ETT increased equally in both treatment arms at 1, 3, 12 months (P=ns). A mean of 12mg/day of furosemide was spared in trandolapril arm (P=0.001). CONCLUSIONS: Trandolapril had a mild diuretic-sparing effect. These results emphasis the importance of explaining to patients that ACE inhibitors provide protection against death and hospitalisation for heart failure but do not have any significant effect upon symptoms.

Aged↗

PubMed1989

Chronic effects of nicorandil on exercise tolerance in patients with stable effort angina pectoris.

To examine the chronic effects of nicorandil, a new coronary vasodilator, on exercise tolerance, we gave this drug for ten days at 15 mg/day orally in three divided doses to 10 patients with stable effort angina. An increase in exercise capacity by more than 1 stage of modified Bruce's protocol was observed in 6 of 10 patients on the 5th and 10th day after the administration. The exercise duration was significantly prolonged from 294 +/- 86 sec (mean +/- SD) before the administration to 363 +/- 106 sec and 405 +/- 139 sec on the 5th and 10th day after the administration, respectively. With nicorandil administration, the time to 0.1 mV of ST-segment depression was also significantly delayed from 3.1 +/- 1.9 minutes to 4.5 +/- 2.6 minutes on the 10th day. On the other hand, systolic blood pressure, heart rate and pressure rate product did not demonstrate any significant change before and after the administration. These results indicate that oral nicorandil of 5 mg 3 times a day can chronically increase exercise tolerance without decreasing myocardial oxygen consumption in patients with stable effort angina.

Adult↗

PubMed2006

Effects of Kanlijian on exercise tolerance, quality of life, and frequency of heart failure aggravation in patients with chronic heart failure.

OBJECTIVE: To observe the effects of conventional therapy combined with Kanlijian (KLJ) on exercise tolerance, quality of life and frequency of heart failure aggravation in patients with chronic heart failure (CHF). METHODS: Sixty CHF patients differentiated as sufferring from the syndrome of Xin-Shen Yang deficiency were included in the study and randomly assigned at the ratio of 2:1 into the KLJ group (n = 39) and the control group (n = 21). All the patients were treated with conventional therapy of Western medicine, but to those in the KLJ group, KLJ was medicated additionally one dose daily with 24 wks as one therapeutic course. The efficacy on TCM syndrome and changes of scores on TCM syndrome were observed after treatment. The indexes, including 6-minute walking distance (6MWD), quality of life (QOL, accessed by LHFQ scoring), NYHA grade, hemodynamic indexes and reducing/withdrawal rate of diuretic and digoxin before and after treatment were recorded and compared. Also the frequency of re-admission due to aggravation of heart failure in one year's time were observed. RESULTS: (1) The efficacy on TCM syndrome, improvement on scores of TCM syndrome, therapeutic effects on 6MWD, QOL, and NYHA grade in the KLJ group were superior to those in the control group. (2) Hemodynamic indexes after treatment, left ventricular fractional shortening (LVFS) and E peak/A peak (E/A), between the two groups had no significant difference, while left ventricular ejection fraction (LVEF) was increased significantly in the KLJ group, but with no obvious change in the control group. (3) The reducing/withdrawal rate of diuretic and digoxin in the KLJ group was significantly higher than that in the control group. (4) The 1-year frequency of re-admission significantly decreased in the KLJ group. CONCLUSION: The adjuvant treatment of KLJ on the basis of Western conventional therapy can significantly improve CHF patients' exercise tolerance, quality of life and cardiac function, reduce the dosage of diuretic and digoxin needed, and decrease the re-admission frequency due to aggravation of heart failure.

Digoxin↗

PubMed2004

Limitation of exercise tolerance in chronic heart failure: distinct effects of left bundle-branch block and coronary artery disease.

OBJECTIVES: The aim of this study was to identify resting measurements of left ventricular (LV) function that predict exercise capacity in dilated cardiomyopathy (DCM); in particular, the effects of left bundle branch block (LBBB), coronary artery disease (CAD), and total isovolumic time (t-IVT). BACKGROUND: The t-IVT is a major determinant of cardiac output during dobutamine stress in DCM, and is itself determined by the presence or absence of LBBB and CAD. METHODS: A total of 111 patients with DCM, 51 with CAD (29 LBBB), and 60 without CAD (30 LBBB) were studied with echocardiography and cardiopulmonary exercise testing. The t-IVT (in s/min) was measured by Doppler echocardiography, and maximal oxygen consumption (peak Vo(2)) and percentage of the normal predicted peak Vo(2) (%predicted peak Vo(2)) were obtained from exercise testing. RESULTS: Left bundle branch block reduced peak Vo(2) (by 10.5 ml.kg(-1)min(-1)) and %predicted peak Vo(2) (by 33%, both p < 0.001) compared with patients without LBBB. Coronary artery disease reduced peak Vo(2) (by 5.5 ml.kg(-1)min(-1), p < 0.001) and %predicted peak Vo(2) (by 14%, p < 0.01) compared with those without CAD (p < 0.01). The t-IVT, CAD, LBBB, and QRS duration were univariate predictors of exercise tolerance, but only t-IVT and CAD were independent predictors. The t-IVT at rest correlated with peak Vo(2) (r = -0.68) and %predicted peak Vo(2) (r = -0.74, both p < 0.001). The combination of t-IVT and CAD explained 57% (r = 0.75, p < 0.001) of the total variance in exercise capacity. CONCLUSIONS: Resting t-IVT and less prominently, CAD, are major determinants of exercise tolerance in DCM. Left bundle branch block significantly determines resting t-IVT and thus peak Vo(2). Prediction of maximum exercise capacity in DCM is therefore possible from time-domain analysis of LV function at rest.

Adrenergic beta-Antagonists↗

PubMed1987

Frequency of painless myocardial ischemia during exercise tolerance testing in patients with and without diabetes mellitus.

To evaluate the frequency of painless myocardial ischemia, all patients with positive exercise tolerance test responses (at least 2 mm of ST depression) from 1983 to 1985 were examined. Of the 211 patients with exercise-induced ischemia, 101 (48%) did not have pain during the ischemic period; 26 (12%) had diabetes mellitus, 24 of whom (92%) had type II diabetes mellitus. Lack of pain was not correlated with age, gender, history of cigarette smoking, systemic hypertension, past acute myocardial infarction, coronary artery bypass grafting, use of beta-blocking or calcium-channel blocking drugs, number of narrowed coronary arteries or average calculated ejection fraction at cardiac catheterization. Patients with painless myocardial ischemia were less often taking nitrates (39% vs 55%, p less than 0.05) and reported prior episodes of chest pain less often (50% vs 82%, p less than 0.01) than control subjects. There was no difference in the frequency of painless myocardial ischemia between patients with and without diabetes mellitus (54% vs 47%). Duration of exercise was shorter in patients with diabetes mellitus and in patients who had pain with myocardial ischemia. No significant difference in age, gender, use of nitrates, beta-blocking or calcium-channel blocking drugs, history of myocardial infarction, angina pectoris or cigarette smoking was found between diabetic and nondiabetic patients. Systemic hypertension was more common in diabetic patients. Thus, painless myocardial ischemia is common in our patients with positive exercise tolerance test responses, but its frequency is similar in diabetic and nondiabetic patients.

Cardiac Catheterization↗

PubMed2000

Effects of amlodipine on exercise tolerance, quality of life, and left ventricular function in patients with heart failure from left ventricular systolic dysfunction.

BACKGROUND: A preliminary study suggested that the long-acting late-generation calcium-channel blocker amlodipine has favorable effects on exercise tolerance and is safe to use in heart failure, in contrast to earlier generation agents. The goal of 2 multicenter studies was to assess the effect of adjunctive therapy with amlodipine in addition to standard therapy on exercise capacity, quality of life, left ventricular function, and safety parameters in patients with heart failure and left ventricular systolic dysfunction. METHODS: Two large multicenter trials examining the effects of amlodipine on these parameters over a 12-week period of therapy were undertaken in patients with mild to moderate heart failure and left ventricular systolic dysfunction. A total of 437 patients with stable heart failure were studied in a randomized, double-blind, placebo-controlled prospective design. RESULTS: Amlodipine at a dose of 10 mg/day in addition to standard therapy in such patients was associated with no significant difference in change in exercise tolerance on a Naughton protocol compared with placebo in each trial. Among all patients taking amlodipine, exercise time increased 53 +/- 9 (SE) seconds; exercise time for those taking placebo increased 66 +/- 9 seconds (P = not significant). There were no significant differences in changes of quality of life parameters between amlodipine- and placebo-treated patients, and there were no significant differences in symptom scores or New York Heart Association classification between groups. Left ventricular function (measured as ejection fraction) improved 3. 4% +/- 0.5% in amlodipine-treated patients and 1.5% +/- 0.5% in placebo-treated patients (P =.007). There was no statistically significant excess of important adverse events (episodes of worsening heart failure in 10% amlodipine-treated vs 6.3% of placebo-treated patients) or differences in need for changes in background medication between groups. CONCLUSIONS: The addition of 10 mg of amlodipine per day to standard therapy in patients with heart failure is associated with no significant improvement in exercise time compared with placebo therapy over a 12-week period, and there was no increased incidence of adverse events. These data suggest that the addition of amlodipine to standard therapy in heart failure will not result in additional efficacy per se beyond standard therapy.

Aged↗

PubMed1982

The effects of nebulized salbutamol on lung function and exercise tolerance in patients with severe airflow obstruction.

The effects of 10 mg of nebulized salbutamol on lung mechanics and exercise tolerance in 10 patients with severe airflow obstruction are described. All patients were previously considered to have irreversible airflow obstruction as demonstrated by little or no improvement in expiratory flow rates either during a corticosteroid trial or after inhalation of 100 micrograms of isoprenaline. There was a small improvement in expiratory flow rate after nebulized salbutamol but the greatest increases were seen in slow vital capacity, inspiratory capacity, inspiratory flow rates, dynamic compliance during tidal breathing, mid-inspiratory and expiratory pulmonary resistance and exercise tolerance. The mechanism of these effects and their therapeutic significance is discussed.

Aged↗

PubMed1983

A clinical approach to exercise tolerance testing in coronary artery disease.

Data from exercise tolerance testing should be incorporated into clinical decision making. A strategy for stratification of individual patients into high, indeterminate, and low-risk categories using Bruce protocol exercise testing is outlined. This approach will help to ensure further evaluation of high-risk individuals without excessive testing of patients having excellent long-term prognoses.

Coronary Disease↗

PubMed1985

Effect of xamoterol (ICI 118587), a new beta1 adrenoceptor partial agonist, on resting haemodynamic variables and exercise tolerance in patients with left ventricular dysfunction.

The effect of xamoterol, a beta1 adrenoceptor partial agonist, on resting haemodynamic measurements and exercise tolerance was studied in 10 patients with dyspnoea of effort. All patients had poor left ventricular function due to myocardial infarction with ejection fractions ranging from 15% to 35% (mean 28%). The cardiac index and stroke work index both rose significantly. The mean pulmonary artery pressure fell from 20(2) mm Hg to 16(2) mm Hg and pulmonary artery wedge pressure from 14(2) mm Hg to 10(2) mm Hg within the first four hours. Exercise tolerance, measured on the treadmill, increased significantly in seven patients but was unchanged in the three who had the lowest left ventricular ejection fractions. Exercise heart rate response was attenuated by the drug in all patients. It is concluded that xamoterol may be beneficial in patients with poor left ventricular function but can be harmful in extremely poor left ventricular function where high sympathetic drive may be important.

Adrenergic beta-Agonists↗