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 1,063 records · Page 59Linked to original sources

PubMed1996

Improved quality of life in chronic heart failure patients following local endurance training with leg muscles.

BACKGROUND: Despite reported benefits of exercising for chronic heart failure patients, limited data are available on quality of life and the effects of different modes of training. This study assessed the effects of local endurance training with knee extensor muscles on exercise tolerance and health-related quality of life in male patients with moderate, chronic heart failure. METHODS AND RESULTS: Twenty-one patients (mean age, 60 years; range, 43-73 years) in New York Heart Association functional classes II-III (ejection fraction, 28 +/- 11%) were randomized to two training groups and one control group. Both training groups performed the same relative quantity of dynamic work with knee extensor muscles 3 days a week for 8 weeks. However, the quantity of muscle mass trained at one time and, consequently, the load on the integrated circulation differed between the groups (two-and one-leg training). Exercise capacity and perceived quality of life were assessed before and after the training or control period. Exercise tolerance increased (P < .01) in both training groups with significantly (P < .01) better improvement in submaximal exercise capacity in the two-leg group. There was no improvement in the control group. Coping capacity did not differ from the reference range and did not change during the study. Global health-related quality of life was depressed at baseline. Training improved (P < .05) health-related quality of life. Compared with the control group, the improvement of health-related quality of life subscales was more pronounced in the two-leg training group (P < .02-.005) as compared to the one-leg training group (not significant to P < .05). CONCLUSIONS: Local muscle endurance training has beneficial effects on exercise tolerance and health-related quality of life in patients with moderate, chronic heart failure. As two-leg training showed a tendency toward better improvement in submaximal exercise capacity and in quality of life than one-leg training, the effects on quality of life appear to be exercise-related in addition to a possible placebo-related effect. Also, the effect appears to be related to the extent of muscle trained at one time.

Adult↗

PubMed1988

Psychological factors influence the success of coronary artery surgery.

Thirty-six patients with angina were investigated by treadmill exercise testing and coronary angiography prior to coronary artery surgery. Severity of angina was judged by interview and self-assessment visual analogue scale and all patients were psychiatrically assessed. Further physical and psychiatric assessments were made at 3 and 6 months postoperatively. Eleven patients (31%) had significant psychiatric morbidity preoperatively and these had worse symptom scores and exercise tolerance compared with non-psychiatric cases, despite equivalent coronary angiographic findings and left ventricular function. Post-operatively, exercise tolerance improved equally in both groups but psychiatric cases remained significantly more symptomatic. Psychiatric morbidity remained unchanged throughout the study. We conclude that almost one third of patients with severe angina have psychiatric morbidity which is associated with a poor symptomatic response to coronary artery surgery, despite objective improvement in exercise tolerance. Ways of improving the symptomatic response to surgery in patients with coexisting psychiatric morbidity should be studied.

Adult↗

PubMed1998

Exercise performance in patients with dilated cardiomyopathy: relationship to resting left ventricular function.

Relationship between maximal exercise tolerance and resting indexes of left ventricular systolic and diastolic function were evaluated in 35 men, aged 55.1 +/- 10.4 years, with dilated cardiomyopathy. Clinical diagnosis of dilated cardiomyopathy was confirmed with M-mode echocardiography (M-mode echocardiographic end-diastolic dimension >55 mm, fractional shortening <25%, increased E point septal separation). Coronary angiography was considered mandatory for exclusion of patients with coronary artery disease. Patients with mitral regurgitation (> or =grade 2) and rhythm other than sinus were excluded. According to the functional classification of New York Heart Association 6 patients were in class I, 11 in class II, 12 in class III and 6 in class IV. Left ventricular ejection fraction (LVEF), stroke volume (SV) and left ventricular end-diastolic pressure (LVEDP) were measured with contrast angiography. Peak early (VE) and late (VA) transmitral filling velocities and their ratio (E/A), isovolumetric relaxation time (IRT) and deceleration time (DT) were computed from pulsed wave Doppler echocardiograms. On completion of all resting measurements, patients underwent symptom limited upright treadmill exercise testing using a modified Naughton protocol and maximal exercise performance metabolic equivalent work load (NETS) was calculated from the speed, incline and length of time at the stage using standard tables to make interpatient comparisons. Significant correlation has been found between NYHA class and METS (r= -0.77, P<0.001). However NYHA class II and NYHA class III patients were found to have similar METS (P=0.317). Patients were further divided into two groups on the basis of exercise data. Group I consisted of 22 patients with relatively preserved exercise tolerance (> or =4 METS) and Group II included 13 patients with impaired exercise tolerance (> or =4 METS). This arbitrary classification was based upon previously described survival differences in these two groups. There were no differences between two groups in terms of age, gender distribution (all were male), heart rate and arterial blood pressure. LVEF, LVEDP, stroke volume, VE, VA, E/A, IRT and DT were also similar between two groups. Strong positive correlation was observed between LVEDP and VE (r=0.74) while IRT and VA negatively correlated with LVEDP (r= -0.77 and r= -0.81 respectively) but neither of resting indexes of left ventricular systolic and diastolic function showed significant correlation with METS and exercise duration.

Cardiomyopathy, Dilated↗

PubMed1990

Comparison of low rate dual chamber pacing to activity responsive rate variable ventricular pacing.

A study was undertaken to evaluate exercise performance in 18 dual chamber pacemaker patients believed to be chronotropically incompetent. All patients were paced in a DDD AV synchronous mode at 80 beats per minute (beats/min) as well as an externally triggered, activity responsive VVIR mode. Patients underwent two single blind, randomized symptom-limited treadmill tests (Sheffield protocol). Four of the 18 patients achieved intrinsic rates greater than 100 beats/min and were deleted from the primary study. It was noted that all four of these patients performed best with intrinsic rate response and AV synchrony. Thirteen of the remaining 14 patients demonstrated improved exercise tolerance in the VVIR mode. Average exercise time in the VVIR mode (7:25 +/- 3:12 min) was significantly greater (P less than 0.05) than the DDD mode (6:01 +/- 2:27 min). Work performed was significantly greater (P less than 0.05) in the VVIR mode (4.77 +/- 1.97 METS) than in the DDD mode (3.78 +/- 0.77 METS). Maximum heart rates were 83.86 +/- 5.11 beats/min in DDD mode versus 116.00 +/- 10.56 beats/min in VVIR mode. The results demonstrated that improved exercise tolerance can be achieved with single chamber rate variable pacing compared to DDD pacing in patients with chronotropic incompetence. However, potential symptoms associated with loss of AV synchrony should be ruled out.

Adult↗

PubMed2005

Long-term serial echocardiographic examination of late anthracycline cardiotoxicity and its prevention by dexrazoxane in paediatric patients.

UNLABELLED: The authors conducted an 8-year prospective non-randomised study to determine whether dexrazoxane (ICRF-187) would reduce late anthracycline-induced cardiotoxicity in patients treated in childhood for haematological malignancy. The authors examined prospectively 75 patients (40 male/35 female) aged 2-17 years (median 6.5 years) at the time of diagnosis. The cardioprotection was given to 53 patients (26 male/17 female) and the standard protocol was used in 22 patients (14 male/8 female). The prospective echocardiographic evaluation was done before and after the chemotherapy and every year during the follow-up period. Dynamic stress echocardiography (DSE) was assessed in the final year. The clinical cardiotoxicity was not diagnosed. Higher cumulative doses of anthracycline were given in the dexrazoxane group (234+/-58 mg/m(2), median 240 mg/m(2) versus 203+/-86 mg/m(2), median 210 mg/m(2), P <0.04) and a significantly higher percentage of patients received cumulative doses >240 mg/m(2) of anthracycline ( P <0.05). During the follow-up period, the fractional shortening (FS) declined in the no-dexrazoxane group only in the 8th year and was significantly lower compared to the dexrazoxane group ( P <0.05). The pathological decrease in FS was present in 24% of patients; 41% in the no-dexrazoxane and 17% in the dexrazoxane groups, respectively ( P <0.05). DSE demonstrated lower rest EF and cardiac index (CI) in the no-dexrazoxane group ( P <0.05); however, neither the response of EF and CI to the stress echocardiography nor the exercise tolerance significantly differed between sub-groups. A higher number of patients in the dexrazoxane group had very good exercise tolerance (ET) >3 Watts/kg ( P <0.05) and a lower number responded with a decreased ET <2 Watts/kg ( P <0.05) compared to the no-dexrazoxane group. CONCLUSION: Dexrazoxane seems to reduce the risk of late subclinical cardiotoxicity. Dexrazoxane-treated patients revealed better exercise tolerance; however the haemodynamic response to the stress was no different in both sub-groups.

Adolescent↗

PubMed2004

[Role of physical training in cardiac rehabilitation in patients with congestive heart failure].

Patients with stable heart failure show decreased exercise tolerance and consequently quality of life. The reduced physical capacity in these patients is a result of decreased strength of skeletal muscles and even their atrophy. The physical activity is limited by metabolic disorders and histological changes in myocytes. Dysfunction of respiratory muscles plays a role in the development of exertional dyspnea. Patients with stable heart failure are recommended to perform low or moderate physical training, which improves exercise tolerance. Intensive physical training in patients with reduced left ventricular ejection fraction improves maximal oxygen consumption through increased left ventricular stroke and increased arteriovenous difference. Recent studies indicate that regular physical training has a positive physiological effect on exercise tolerance, and decreases dyspnea and fatigue, in many patients with heart failure.

Dyspnea↗

PubMed1976

Exercise tests before and after heart valve replacement.

A simple progressive exercise test was performed before and after operation on five subjects undergoing mitral valve replacement and on five subjects undergoing aortic valve replacement. The responses of heart rate and ventilation were related to work rate )kilopond metres/min). The patients were also assessed clinically by the New York Heart Association grading and radiologically before each exercise test. The clinical grading was shown to be a poor guide to observed exercise tolerance, as the improvement noted in symptoms was not matched by the objective measurement of working capacity. Only two patients had normal exercise tolerance after surgery, although six of the ten patients claimed that they had no exertional dyspnoea after operation. The changes in simple ventilatory function tests before and after operation were generally small. We suggest that measurements of exercise tolerance before and after operation should be an essential part of heart valve replacement surgery.

Adult↗

PubMed1993

Nasal continuous positive airway pressure in chronic heart failure with sleep-disordered breathing.

Nasal continuous positive airway pressure (NCPAP) has been reported to improve daytime symptoms in patients with sleep disordered breathing due to heart failure. To examine this in a controlled manner, eight men with stable chronic heart failure (mean left ventricular ejection fraction 18% and mean frusemide dose 160 mg) were entered into a controlled trial of domiciliary nocturnal NCPAP. At polysomnography (with sleep apnea quantified as the number of > 4% dips in arterial saturation per hour), seven had nocturnal Cheyne-Stokes respiration (SaO2 dip rate 3 to 27/hr), and one both central and obstructive apneas (SaO2 dip rate 8/hr). After 2 wk nocturnal domiciliary NCPAP at < 1.5 cm H2O (placebo) and 7.5 cm H2O (active) in random order, bicycle exercise tolerance and heart failure symptoms (modified Likert questionnaire) were assessed by an observer unaware of the patients' NCPAP status. Pulse oximetry (all subjects) and radionuclide estimated left ventricular ejection fraction (three subjects) were also measured at the end of each period. Two subjects withdrew from the study because of worsening heart failure during active NCPAP (7.5 cm H2O), and one of these subjects died. In the remaining six subjects exercise tolerance, symptom scores, and the severity of sleep apnea were similar on active NCPAP compared with placebo. When it was measured, resting left ventricular ejection fraction was lower on active therapy than on placebo. These data exclude a 25% improvement in exercise tolerance with 95% confidence and suggest that a study of 160 subjects would be needed to exclude a 10% change in symptom score.(ABSTRACT TRUNCATED AT 250 WORDS)

Cheyne-Stokes Respiration↗

PubMed2005

Clinical correlation and prognostic predictive value of neurohumoral factors in patients late after the Fontan operation.

AIMS: We tested the hypothesis that neurohumoral activation could correlate with exercise tolerance and have a prognostic value in patients late after Fontan operation. METHODS AND RESULTS: We studied 50 consecutive patients after the Fontan operation and 10 age-matched normal controls. We measured brain and atrial natriuretic peptides, norepinephrine (NE), plasma rennin activity, aldosterone, angiotensin II, and endothelin and investigated the relationship of neurohumoral factors with exercise tolerance and central hemodynamics. We also evaluated the prognostic predictive value of these factors. All factors were significantly higher in the patients than in controls, but no factor correlated with peak oxygen consumption (peak VO2). There were significant correlations of atrial natriuretic peptide with cardiac index, NE with left ventricular ejection fraction (LVEF), and pulmonary arterial wedge pressure. After 4 years' follow-up, univariate Cox proportional hazards analysis showed that peak VO2 and LVEF could significantly predict the long-term event-free ratio. In multivariate analysis, LVEF and NE have a significant predictive value. In Kaplan-Meier event-free curves, NE combined with peak VO2 showed a significant predictive value. CONCLUSIONS: Activated neurohumoral factors are not determinants of exercise tolerance in patients late after the Fontan operation. The plasma level of NE combined with peak VO2 has a prognostic predictive value in these patients.

Adolescent↗

PubMedDate not supplied

Angiotensin type-1 receptor blockers in heart failure.

Chronic heart failure is a common condition with a poor prognosis, usually associated with poor exercise tolerance and debilitating symptoms despite optimal modern therapy. Standard therapy includes diuretics, digoxin, angiotensin-converting enzyme inhibitors (ACEIs) and beta-blockers. Despite this, many patients remain symptomatic, and interest is high as to whether the angiotensin receptor blockers (ARBs) would offer further advantage to a patient already receiving quadruple therapy. In addition, some patients are intolerant of ACEIs, and for this group the ARBs seem a logical choice. This article reviews the evidence for the use of ARBs as a class in heart failure concentrating on clinical recommendations and clinical needs and evidence rather than purely on statistical issues of significance in trials. The trials to date have demonstrated clearly similar hemodynamic effects to those seen with ACEIs and variety of ancillary benefits such as improvements in endothelial function, anti-thrombotic effects, and effects on neurohormonal inhibition. There is consistent evidence of a preservation of exercise tolerance when patients with heart failure are crossed over from stable ACEI therapy, and when added to ACEIs exercise tolerance appears to increase with ARBs. In terms of major outcomes, the two largest trials, Elite-II and Val-Heft, demonstrate that angiotensin receptor blockers probably have a clinical role in improving mortality and morbidity as an alternative to ACEIs in those patients unable to tolerate these agents, which remain, however, the first choice in unselected patients with heart failure. There is a worrying suggestion of a negative interaction when ARBs are added to beta-blockers, which is a reason for caution in using the ARBs, not a reason not to use beta-blockers.

Angiotensin Receptor Antagonists↗

PubMed2000

Nicorandil. An updated review of its use in ischaemic heart disease with emphasis on its cardioprotective effects.

Nicorandil is a drug with both nitrate-like and ATP-sensitive potassium-channel (K+ ATP) activating properties. By virtue of this dual mechanism of action, the drug acts as a balanced coronary and peripheral vasodilator and reduces both preload and afterload. The K+ ATP channel has been shown to be involved in the phenomenon of myocardial preconditioning, and studies in animal models of ischaemia-reperfusion-induced myocardial stunning or infarction indicate that nicorandil has cardio-protective effects. Studies in patients undergoing percutaneous transluminal coronary angioplasty (PTCA) have shown that the administration of nicorandil reduces ST-segment elevation during ischaemia. Nicorandil significantly improved the results of exercise tolerance tests versus baseline in patients with stable effort angina pectoris in early noncomparative trials. The drug also improved the results of exercise tolerance tests relative to placebo in early randomised, double-blind, placebo-controlled trials. In randomised, double-blind comparative studies in patients with angina pectoris, nicorandil has demonstrated equivalent efficacy, as measured by exercise tolerance testing, to isosorbide di- and mononitrate, metoprolol, propranolol, atenolol, diltiazem, amlodipine and nifedipine. The effects of nicorandil on various aspects of myocardial recovery from ischaemic damage caused by acute myocardial infarction have been investigated in the short term. Regional left ventricular (LV) wall motion, a marker of myocardial function, was significantly improved in nicorandil recipients relative to control. The main adverse event associated with nicorandil as treatment for angina pectoris is headache. This can be minimised by commencing nicorandil at a low dose in patients prone to headache. There have been infrequent case reports of mouth ulcers in patients receiving nicorandil; causality has not been conclusively established, but product prescribing information indicates that an alternative treatment should be considered if persistent aphthous or severe mouth ulceration occurs. Thus, nicorandil remains a useful background therapy for patients with angina pectoris. The drug has also demonstrated potential cardioprotective effects when used as part of an intervention strategy directly after acute myocardial infarction in high-risk patients. Further large scale longer term studies of nicorandil in this latter indication are awaited with interest.

Angina Pectoris↗

PubMed1982

Variability of response to beta receptor blockade for angina pectoris in clinical trials: a study of pindolol.

In a randomized, controlled study we found a significant decrease in pressure-rate (double) product and an improvement in exercise tolerance in patients with angina pectoris treated with pindolol. However, when patients were observed in a long-term double-blind crossover study, pindolol treatment did not produce a significant improvement in angina pectoris or exercise tolerance over placebo. Patients treated with placebo had a gradual improvement in exercise tolerance, possibly because of the training effect of multiple treadmill tests and increased daily walking. The individual patient response to pindolol varied, with some patients showing clinical improvement and decreased double product with exercise and some having no clinical improvement despite a similar decrease in double product. Angina occurred at a lower double product with exercise, suggesting that beta receptor blockade adversely affected other variables of myocardial oxygen demand or decreased coronary blood supply. This study illustrates the difficulties with patient variability and study design that are encountered in studies of beta blocker agents for angina pectoris.

Adrenergic beta-Antagonists↗

PubMed1999

[Assessing the physiologic significance of intermediate coronary lesions: comparison of coronary flow measurements with exercise electrocardiography].

Angiography may provide limited assessment of intermediate coronary stenoses. Doppler coronary flow reserve has been applied to determine the physiologic significance of such lesions. This study compared coronary flow reserve derived from intracoronary Doppler flow wire with the results of the exercise tolerance test to evaluate the validity of intracoronary flow measurements in the assessment of intermediate stenoses. Sixty eight patients with 91 vessels harboring angiographically mild-to-severe coronary stenoses in the left anterior descending or right coronary artery were studied. All patients had single-vessel disease, and angiography showed the target vessel. Distal coronary flow reserve was measured with the Doppler guide wire during cardiac catheterization. Exercise tolerance tests by bicycle ergometer were performed the day before catheterization. Quantitative coronary angiography showed a mean percentage diameter stenosis of 44 +/- 21%(range 0-90%). Forty seven of 91 vessels combined intermediate lesions(40% to 70%). Percentage diameter stenosis and coronary flow reserve were linearly correlated in both overall and intermediate lesions(r = -0.52 vs -0.42; both p < 0.0001). Percentage diameter stenosis of overall lesions was significantly higher in the positive exercise test group than the negative group(59.8 +/- 17.2% vs 37.7 +/- 18.1%, p < 0.0001), but not significantly different in intermediate lesions(49.1 +/- 7.8% vs 54.7 +/- 6.6%, p = 0.03). The positive exercise test group showed significantly lower coronary flow reserve compared to the negative group in both overall and intermediate lesions(overall: 1.6 +/- 0.5 vs 2.6 +/- 0.9, p < 0.0001; intermediate: 1.6 +/- 0.5 vs 2.5 +/- 0.7, p < 0.0001). Coronary flow reserve < 2.0 and positive exercise test agreed in 38 of 46 intermediate lesions(83%), and percentage diameter stenosis > or = 50% and positive exercise test agreed in 34 of these 46 lesions(74%). Coronary flow reserve, more than percentage diameter stenosis, correlated with the results of the exercise tolerance test, and is considered to be useful to evaluate the functional severity of intermediate stenosis.

Aged↗

PubMed1984

The isolated lateral retinacular release in the treatment of patellofemoral disorders.

Isolated lateral retinacular release was performed on 102 knees in 76 patients. Diagnoses included chondromalacia patellae, patellar compression syndrome, and subluxation and dislocation of the patella. Patients reported that their symptoms improved after isolated lateral retinacular release in 95 of 102 knees. At follow-up evaluation (mean, 14.5 months after surgery), independent observers found no recurrence of dislocation in the 23 knees having had frank dislocations before surgery. In 71% of the knees with limitation of activity before surgery, unlimited activity was tolerated after isolated lateral retinacular release. Quadriceps exercise tolerance improved from 51% before surgery to 100% after surgery. This improvement in exercise tolerance can provide a significant length of time in which quadriceps rehabilitation can be conducted. Hypothetically, the effect of that lateral retinacular release is a decrease in the work load of an overpowered or weakened vastus medialis obliquus muscle, the major provider of dynamic stability required by the patellofemoral joint.

Adolescent↗

PubMed1999

[The efficacy and practice of exercise training in patients with chronic obstructive pulmonary disease (COPD)].

Exertional dyspnea is a most popular symptom in COPD patients often lead to exercise intolerance. Indeed the reduced activity in patient's daily life due to dyspnea may lead to deconditioning and peripheral muscle weakness. Bronchodilators and anti-inflammatory drugs are an important treatment to reduce symptoms and improve airflow limitation but not improve deconditioning. Impairment of exercise tolerance is a common problem in patients with COPD and therefore exercise training is an important component of all pulmonary rehabilitation programs. It is now clearly established that exercise training reduce dyspnea, improve exercise tolerance and improve activities of daily living (ADL) and health related quality of life (QOL). Oxygen therapy during exercise are often considered in the COPD patients with exercise induced hypoxemia.

Activities of Daily Living↗

PubMed2006

Efficacy and safety of controlled-release isosorbide-5-mononitrate in Japanese patients with stable effort angina pectoris.

A new controlled-release isosorbide-5-mononitrate (CR-ISMN) preparation has been developed to meet the requirement for a low nitrate concentration interval in order to avoid nitrate tolerance. We conducted a randomized, double-blind, placebo-controlled study in 31 Japanese patients with stable effort angina pectoris to investigate the efficacy and safety of CR-ISMN. Patients were randomly assigned to either CR-ISMN (40 mg once daily) or placebo groups for 2 weeks after two consecutive symptom-limited treadmill exercise tests using the Bruce protocol to ascertain the reproducibility of exercise tolerance during the placebo run-in period. Exercise tests were repeated at 5, 12, and 24 hours after administration on the final day. No significant difference in exercise time to moderate angina was identified between the CR-ISMN and placebo groups at 5, 12, or 24 hours after administration. However, the changes in exercise were prolonged at 5 hours but not shortened at 24 hours in the CR-ISMN group. The results of subgroup analysis suggested that the concomitant use of insulin might lead to confounding results. Although headache was the most frequent adverse effect in the CR-ISMN group, all symptoms were mild and at self-limiting levels. The plasma concentrations of CR-ISMN maintained therapeutic levels at 5 and 12 hours, and gradually decreased to less than the minimum therapeutic concentration (100 ng/mL) at 24 hours after administration. This study demonstrates that CR-ISMN improves exercise tolerance during the daytime and is well-tolerated in Japanese patients with stable effort angina pectoris without increasing the number of serious adverse effects.

Aged↗

PubMed2003

Exercise intolerance during post-MI heart failure in rats: prevention with supplemental dietary propionyl-L-carnitine.

Exercise capacity in patients with several types of cardiovascular disease can be improved with dietary carnitine, or carnitine derivatives. Mechanisms underlying this improvement remain largely unknown in part due to a lack of animal models of cardiac pathology in which carnitine derivatives improve exercise tolerance. Our goal was to evaluate the ability of propionyl-L-carnitine (PLC) to improve exercise tolerance in a rat model of exercise intolerance. Fischer 344 rats were followed after either a moderate size MI (n = 22) or sham MI surgery (n = 14). Starting 10 days post-surgery 10 of the MI and 7 of the sham rats received 100 mg/kg/day PLC in drinking water, which increased plasma and LV total l-carnitine concentrations 15-23% (p < 0.05). Rats were followed longitudinally until a statistically significant decrease in exercise capacity occurred in one of the groups, at which time all rats were sacrificed for study of the isolated perfused hearts. At 12-weeks post-MI exercise capacity had decreased 16 +/- 7% (p < 0.05) in the MI group, but remained within 3% of baseline in the MI group that received PLC and the sham groups. Both MI groups exhibited the same degree of LV dilation, decrease in fractional shortening, and blunting of the response to isoproterenol. We conclude that supplemental dietary PLC attenuates the exercise intolerance that occurs secondary to post-MI heart failure in rats, but that this beneficial effect is not attributable to altered LV remodeling, an improved response to beta-adrenergic stimulation, or increased skeletal muscle citrate synthase activity.

Animals↗

PubMed2000

Oral magnesium therapy improves endothelial function in patients with coronary artery disease.

BACKGROUND: Magnesium blocks many of the physiological actions of calcium. Nevertheless, the impact of magnesium supplementation on endothelial function and exercise tolerance in stable coronary artery disease (CAD) patients has not been assessed. METHODS AND RESULTS: In a randomized, double-blind, placebo-controlled trial, 50 stable CAD patients (41 men and 9 women, mean+/-SD age 67+/-11 years, age range 42 to 82 years) were randomized to receive either magnesium (n=25) (30 mmol/d Magnosolv-Granulat; Asta Medica Company, Inc) or placebo (n=25) for 6 months. Before and after 6 months, endothelium-dependent brachial artery flow-mediated vasodilation (FMD) and endothelium-independent NTG-mediated vasodilation were assessed with high-resolution (10-MHz) ultrasound. Exercise stress testing was performed with use of the Bruce protocol. Intracellular magnesium concentrations ([Mg(2+)](i)) were assessed from sublingual cells through x-ray dispersion (EXA) (normal mean+/-SD values 37. 9+/-4.0 mEq/L). The magnesium therapy significantly increased postintervention ([Mg(2+)](i) versus placebo (36.2+/-5.0 versus 32.7+/-2.7 mEq/L, P<0.02). There was a significant correlation in the total population between baseline [Mg(2+)](i) and baseline FMD (r=0. 48, P<0.01). The magnesium intervention resulted in a significant improvement in postintervention FMD (15.5+/-12.0%, P=0.02 compared with baseline), which was not evident with placebo (4.4+/-2.5%, P=0.78 compared with baseline). There was better exercise tolerance (9.3+/-2.0 versus 7.3+/-3.1 minutes, P=0.05) and less ischemic ST-segment changes (4 versus 10 patients, P=0.05) in the magnesium versus placebo groups, respectively. CONCLUSIONS: Oral magnesium therapy in CAD patients is associated with significant improvement in brachial artery endothelial function and exercise tolerance, suggesting a potential mechanism by which magnesium could beneficially alter outcomes in CAD patients.

Administration, Oral↗