Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0015672 (fatigue)
 51,768 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The reduced maximal exercise capacity of patients with heart failure has been attributed to skeletal muscle underperfusion with resultant intramuscular lactic acidosis and muscular fatigue. To investigate this hypothesis, the effect of dichloroacetate, a drug that decreases lactate formation by increasing pyruvate oxidation, on the maximal exercise performance of 18 patients with heart failure and reduced ejection fraction (25 +/- 9%) was examined. Exercise tests after parenteral dextrose (control) and dichloroacetate were performed 1 week apart. The sequence of interventions was randomized in a double-blind manner. Dichloroacetate decreased blood lactate at rest (control 8.0 +/- 2.5 versus dichloroacetate 5.6 +/- 2.9 mg/dl), throughout exercise and at peak exercise (control 26.0 +/- 14.3 versus dichloroacetate 19.4 +/- 10.8) (all p less than 0.05). In contrast, dichloroacetate had no effect on exercise time (control 15.2 +/- 6.0 versus dichloroacetate 15.9 +/- 6.2 min) or peak exercise oxygen consumption (control 1,280 +/- 498 ml/min versus dichloroacetate 1,312 +/- 530 ml/min) (both p = NS). In six subjects, dichloroacetate also had no effect at peak exercise on leg blood flow (control 2.8 +/- 1.1 versus dichloroacetate 3.0 +/- 0.6 liters/min) or femoral oxygen vein saturation (control 12.7 +/- 4.1% versus dichloroacetate 12.5 +/- 5.7%). These data suggest that intramuscular lactate accumulation is not responsible for muscular fatigue during exercise in patients with heart failure.
J Am Coll Cardiol 1988 Dec
PMID:Effect of dichloroacetate on the exercise performance of patients with heart failure. 319 43

Patients with heart failure frequently report leg fatigue during exercise. At present, however, there is no objective method of detecting leg muscle abnormalities in such patients. To determine if phosphorus-31 nuclear magnetic resonance spectroscopy can provide such information, this technique was used to compare calf responses to stair climbing and plantarflexion in 20 patients with heart failure (peak oxygen consumption (VO2) of 13.6 +/- 5 ml/kg/min, ejection fraction 20 +/- 5%) and 9 age-matched normal subjects. Work was quantified by measuring VO2. At rest, both groups exhibited similar inorganic phosphorus to phosphocreatine (Pi/PCr) ratios (patients with heart failure 0.21 +/- 0.07, normal subjects 0.21 +/- 0.06, difference not significant) and pH levels (patients with heart failure 7.06 +/- 0.17, normal subjects 7.05 +/- 0.11, difference not significant). In both normal subjects and patients with heart failure, exercise resulted in a progressive rise in Pi/PCr as VO2 increased. However, examination of the relation of VO2 versus Pi/PCr revealed steeper slopes in patients with heart failure during both stair climbing and plantar-flexion. Neither form of exercise decreased calf pH in normal subjects. In the patients with heart failure, significant decreases in pH were noted during the highest work level of plantarflexion (pH of heart failure patients 6.86 +/- 0.20, pH of normal subjects 7.07 +/- 0.14, p less than 0.01). Metabolic recovery time was also prolonged in the patients with heart failure versus normal subjects (3.3 +/- 0.8 vs 2.1 +/- 0.5 minutes, respectively, p less than 0.002). These findings indicate that phosphorus-31 nuclear magnetic resonance provides objective evidence of leg muscle abnormalities in patients with heart failure.(ABSTRACT TRUNCATED AT 250 WORDS)
Am J Cardiol 1988 Dec 01
PMID:Detection of abnormal calf muscle metabolism in patients with heart failure using phosphorus-31 nuclear magnetic resonance. 319 84

We investigated exercise capabilities of the elderly patients with significant coronary artery lesions and angina pectoris. The heart rate increased according to workload, but there were few cases in which maximal heart rate was obtained. There was a marked increase in VO2 at endpoint before sufficient work load was achieved. It suggested an increase in O2 demand of the myocardium and entire body. Left ventricular dysfunction from skeletal muscle fatigue and work load-induced myocardial anoxia were also suggested. The conditions of coronary arteries of aged patients and the method of treatment were studied on the basis of coronary angioplastic findings and exercise tolerance. We reviewed percutaneous transluminal coronary angioplasty (PTCA) performed in 49 aged patients (older than 70 years) with angina and investigated long-term results. In this group including 18 patients (43%) with multivessel disease, there was a high success rate (90%), and significant improvements in workload responses were achieved in early stages after PTCA. The rate of recurrence was higher in this group than non aged patients, however, angioplasty was repeated successfully in all of the patients. Dilated sites were recognized as patent in a majority of patients. Late cardiac events occurring six months after PTCA were acute myocardial infarction in only one case (2.2%) and unstable angina in three cases (6.8%). There was no cardiac death. The five-year cumulative survival rate was high (97%). During a follow-up interval of averaged 32 months, chest pain disappeared in 70% of patients and 48% enjoyed daily life without restriction. Since the quality of life appears to be improved and long term results are sufficiently acceptable, we concluded that PTCA is highly recommended for the elderly patients.
J Cardiol Suppl 1988
PMID:[Clinical characteristics of ischemic heart disease in the aged: significance of coronary revascularization and role of PTCA]. 327 11

The most common symptoms of patients with heart failure are shortness of breath and fatigue. The causes of these symptoms may be different in various entities encompassed by the general term heart failure, such as acute pulmonary edema, circulatory collapse and chronic heart failure. In patients with acute heart failure, shortness of breath is closely related to left atrial pressure. In patients with chronic heart failure, optimally treated with diuretics, the body fluid compartments are usually of normal size. Recent work strongly suggests that, in such patients, central hemodynamic abnormalities are not the sole determinants of symptoms. Impaired vasodilation and altered metabolism in skeletal muscle, circulating metabolites and pulmonary ventilation-perfusion mismatch with consequent increased physiologic dead space may all contribute to the genesis of symptoms. Consequently, it may be possible to alleviate symptoms by treatments that are not aimed directly at improving central hemodynamics. Whether such an approach could also modify prognosis is unknown.
Am J Cardiol 1988 Jul 11
PMID:Causes of symptoms in chronic congestive heart failure and implications for treatment. 329 93

Mitral valve prolapse (MVP) is due to a heterogeneous group of conditions that may affect the mitral valve or the mitral valve apparatus. Although MVP may progress later in life to frank mitral insufficiency requiring mitral valve repair or may predispose to bacterial endocarditis, in most cases it is a benign, idiopathic condition without serious consequences. However, many investigators have documented that MVP is often associated with a constellation of signs and symptoms, which appear to constitute a distinct syndrome. These associated findings include autonomic dysfunction, frequent complaints of chest pain, palpitations, orthostasis, fatigue, dyspnea on exertion and anxiety. Although the risk of significant myocardial dysfunction or bacterial endocarditis appears to be related to patient sex, age and the severity of valvular prolapse and insufficiency, there appears to be little or no relations between the extent of prolapse and the degree of autonomic dysfunction or the severity of symptoms of chest pain, palpitations, dyspnea on exertion and anxiety. The development of uniform diagnostic standards for mental disorders has helped to make it possible to identify several related entities, including generalized anxiety disorder, panic disorder and agoraphobia; patients with these disorders frequently somatize their anxiety and complain of many symptoms which may be seen in patients with MVP. Although several studies have reported an increased frequency of MVP in patients with anxiety disorders, recent studies suggest that the conditions are not linked. Iatrogenic cardiac neurosis is common in both groups of patients.(ABSTRACT TRUNCATED AT 250 WORDS)
Am J Cardiol 1987 Dec 28
PMID:Mitral valve prolapse: from syndrome to disease. 332 70

Although both time domain and frequency domain analysis of signal-averaged electrocardiograms (ECGs) may distinguish patients with and without sustained ventricular tachycardia, it remains unclear which method is superior. Both methods were assessed in 55 subjects comprising 26 patients with sustained ventricular tachycardia (Group I), 18 control patients with organic heart disease but without sustained ventricular tachycardia (Group II) and 11 normal volunteers (Group III). Time domain analysis was performed with high pass filtering of 25, 40 and 80 Hz and low pass filtering of 250 Hz. Frequency domain analysis was performed on the terminal 40 ms of the QRS complex, either alone or with 216 or 150 ms of the ST segment. Absolute summed energies of discrete frequency bands and band energy ratios were calculated. The effectiveness of discrimination between Groups I and II was evaluated in terms of group means, sensitivity, specificity and an information content index based on receiver operating characteristic curve analysis. Group I showed a uniform decrease in amplitude across all frequencies derived from the terminal 40 ms of the QRS complex (p less than 0.005). This was abolished by the inclusion of ST segment data in frequency domain analysis. No frequency band was unique for Group I. At a specificity of 78%, the best time domain sensitivity was 85%, and the best frequency domain sensitivity was 77%. The best time domain information content index was 0.156, the best index for frequency domain analysis was 0.077 using absolute band areas. It is concluded that patients with sustained ventricular tachycardia have decreased energy content across all frequencies in the terminal 40 ms of the QRS complex. Frequency domain analysis was not an improvement over time domain analysis in differentiating patients with ventricular tachycardia from those without.
J Am Coll Cardiol 1988 Feb
PMID:A comparative study of frequency domain and time domain analysis of signal-averaged electrocardiograms in patients with ventricular tachycardia. 333 68

Primary cardiac tumor is an extremely rare disease entity. Only three cases of primary malignant cardiac schwannoma, the subject of this report, have been recorded in Japan. Recently, we encountered a case of malignant schwannoma in which retention of pericardial effusion was the first clinical finding. This case was a 30-year-old female, who had dyspnea at work, general fatigue, and fever. Striking cardiac expansion was seen, with a cardiothoracic ratio (CTR) of 69% on chest x-ray. Two-dimensional echocardiograms showed a large volume of pericardial effusion between the side wall of the left ventricle and the epicardium, and the presence of a parenchymatous tumor. An increase in tumor size was detected on chest computer tomography (CT) scan. Using a pump oxygenator, median sternotomy was performed to reach the epicardium. A pale yellow, soft tumor was seen in the left atrium near the left ventricle. Histologically, the patient was diagnosed as having a malignant schwannoma. We have reported a case of primary malignant schwannoma which was surmised to have arisen from the boundary between the atrium and the ventricle.
Clin Cardiol 1988 Feb
PMID:Malignant schwannoma of the heart. 334 6

Sixty-five patients with ST elevation were retrospectively studied in order to evaluate the clinical significance and underlying mechanisms of ST-segment elevation during exercise. Of these, 50 patients had previous myocardial infarction (Group I) and 15 patients did not (Group II). Exercise thallium-201 imaging was performed on 30 patients, resting gated blood pool imaging was performed on 33 patients, and 23 underwent cardiac catheterization for clinical indications. When the two groups were compared, patients in Group I had more frequent multivessel disease (9/13 vs. 3/10, p less than 0.05), anterior infarctions (33/50 vs. 4/10, p less than 0.02), while Group II patients had more frequent single-vessel disease (7/10 vs. 4/13, p less than 0.05). For Group I patients, the most common reason for termination of exercise was fatigue and/or dyspnea (35/50 vs. 0/15, p less than 0.05), with an irreversible defect noted in both stress and delayed views on thallium imaging (20/24 vs. 1/6, p less than 0.05). In Group II, the most common reason for termination was angina (15/15 vs. 2/50, p less than 0.001), with reversible thallium defects noted more frequently (4/6 vs. 3/24, p less than 0.01). Thus, we conclude that in patients with Q waves, left ventricular dysfunction rather than ischemia is the mechanism for ST elevation. In these patients angina is rare, but fatigue, dyspnea, multivessel disease, and fixed thallium defects are common. In patients with non-Q-wave exertional ST elevation, ischemia is the rule, manifested by frequent chest pain and reversible thallium defects.
Clin Cardiol 1988 Mar
PMID:The role of ischemia and ventricular asynergy in the genesis of exercise-induced ST elevation. 335 73

Two series of consecutive patients with disabling effort angina were studied prospectively. From the first series, 94 survivors were followed up 9 months after coronary artery bypass grafting. Thirty-five patients (37%) reported that they still suffered from effort angina. Another 26 patients (28%) also used to stop when walking uphill/upstairs but because of dyspnea and 2 (2%) because of leg fatigue. A symptom-limited exercise test performed in 24 of the 26 with dyspnea revealed effort angina in 2 patients and high-degree dyspnea (mean grade 6.6 of 10) in 22. The exercise capacity was less than normal in 16 of these 22 patients. The number of peripheral anastomoses did not differ between the 26 dyspnea patients and the 31 free from effort restriction, nor did the incidence of perioperative infarctions or treatment with diuretics and beta-blocking drugs at follow-up. The second series of 95 survivors confirmed the high prevalence of disabling dyspnea after coronary artery bypass grafting (24%) and showed that it was not predictable. We conclude that physical fitness is restored in less than half the patients undergoing coronary artery bypass grafting.
Int J Cardiol 1986 Jun
PMID:Effort dyspnea after coronary artery bypass grafting. 348 10

The 24-hour duration of the antihypertensive effect of guanfacine, a centrally acting alpha 2-adrenoceptor agonist administered once a day, was demonstrated in a 12-week, multicenter, double-blind, placebo-controlled study. Two hundred and forty-nine patients who remained mildly to moderately hypertensive following a 5-week period, during which they had been weaned from previous antihypertensive medications and stabilized on 25-mg chlorthalidone taken once a day, were involved. Of the 249 patients, 126 received guanfacine as a step-2 agent and 123 received placebo. Both groups were further subdivided so that blood pressure (BP) measurements were determined either 12 or 24 hours after dosing. The initial dose of guanfacine was 1 mg/day, which could be raised 1 mg at 2-week intervals to a maximum daily dose of 3 mg/day at the discretion of each investigator. The daily dose could also be lowered by 1 mg at 2-week intervals, depending on patient response. The mean 24-hour reductions with guanfacine in sitting diastolic BP (-11 mm Hg), systolic BP (-14 mm Hg) and mean arterial pressure (-12 mm Hg) were statistically significant (p less than 0.01) compared with the reductions in BP with placebo. Heart rate also decreased with guanfacine, but no clinically relevant bradycardia (less than 60 beats/min) was observed. Dry mouth (47%), constipation (16%), fatigue (12%) and drowsiness (4%) were the most frequently reported side effects. The highly acceptable side-effects profile of guanfacine was also indicated by the small percentage of patients (7%) who prematurely left the study because of adverse reactions.
Am J Cardiol 1986 Mar 28
PMID:Usefulness of low dose guanfacine, once a day, for 24-hour control of essential hypertension. 351 29


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