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 pharmacokinetics, clinical efficacy, and adverse effects of three calcium-channel blocking agents--verapamil, nifedipine, and diltiazem--are reviewed. Verapamil, nifedipine, and diltiazem are absorbed well after oral dosing, but absolute bioavailability of each is reduced substantially by a first-pass effect. Each drug is metabolized extensively (verapamil and diltiazem to moderately active metabolites) by the liver. A substantial percentage of each drug is bound to plasma proteins, but the binding is of clinical importance only for nifedipine (92--98% protein bound). Intravenous verapamil has become the agent of first choice for treatment of acute paroxysmal supraventricular tachycardia (PSVT); use of chronic oral verapamil therapy for prophylaxis remains controversial. Verapamil and diltiazem have been evaluated with mixed results for atrial flutter and fibrillation. For treatment of myocardial ischemia, calcium-channel blockers may be of some value (possibly in combination with nitrates of B blockers). All three agents have been studied in patients with exertional angina with good results. Calcium-channel blockers appear to be equal with nitrates for treatment of variant angina. Patients with hypertropic cardiomyopathy have been treated with verapamil and nifedipine with promising results. Nifedipine has been effective for treatment of essential hypertension. Adverse effects of calcium-channel blockers have been relatively minor or infrequent. Diltiazem overall has the best side-effect profile, with adverse effects causing discontinuation of therapy in about 2--10% of patients; verapamil in intermediate (8--10%) and nifedipine the worst (17%) in this respect. The most common side effects generally are fatigue, headache, dizziness, skin rash, and peripheral edema. While they generally should be reserved for patients in whom more conventional therapy has failed (except those with PSVT), calcium-channel blockers appear to have a valid role as reserve agents for exertional and variant angina, cardiomyopathy, and hypertension.
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PMID:Update on calcium-channel blocking agents. 635 66

Endorphins and endorphin receptors are believed to modulate pain perception. To investigate whether naloxone, a specific antagonist, could initiate anginal pain during exercise-induced myocardial ischemia in asymptomatic patients with angiographically defined coronary artery disease, a single-blind trial was conducted in 10 men with prior positive exercise electrocardiograms. Multistage treadmill exercise tests were performed twice within a week. On the second test, patients received naloxone, 2 mg intravenously, by a syringe infusion pump. Exercise was terminated because of fatigue in 6 patients and completion of the protocol in 4. No patient reported chest pain during exercise. Naloxone did not significantly alter exercise duration, heart rate, blood pressure and ST-segment changes compared with control testing. It is concluded that endorphins do not play a significant role in the recognition of anginal pain in patients who have asymptomatic exercise-induced ischemia.
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PMID:Naloxone and asymptomatic ischemia: failure to induce angina during exercise testing. 649 61

Visual monitoring at the central station of coronary care units (CCUs) may not adequately assess the presence and frequency of transient asymptomatic ST segment changes in patients with unstable angina. We have performed continuous 24-h electrocardiographic recordings over a total period of 50 days in 10 patients admitted to our CCU with frequent attacks of angina at rest. Over the corresponding period, at the central monitoring station (6 beds), the nursing-staff detected only 31 transient ischaemic episodes (27 with ST elevation, 4 with depression, 9 of which were asymptomatic). By contrast the retrospective analogue analysis of tapes identified 213 ischaemic episodes: 143 with ST elevation (greater than or equal to 0.2 mV) and 70 with ST depression (greater than or equal to 0.2 mV); usual CCU monitoring failed to report changes during 13 episodes (8 with ST elevation, 5 with depression) accompanied by anginal pain. When the tapes were played back in real time on a CCU monitoring scope, a cardiologist (who had the option of interrupting the play-back whenever tired) recognized 48% of the episodes when presented in groups of 4 and randomly positioned on the screen together with 2 other electrocardiographic tracings not related to the study; he recognized 92% of the episodes when only one ECG was presented on the screen. Thus conventional visual monitoring in a CCU considerably underestimates the incidence of transient ischaemic ST segment changes, some of which were accompanied by pain. This low rate of detection is the result of the presentation on the central monitoring station of several ECGs and of fatigue.
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PMID:Unreliability of conventional visual electrocardiographic monitoring for detection of transient ST segment changes in a coronary care unit. 649 51

Between 1978 and 1983, 1391 exercise tests were performed by 1083 males and 308 females over 64 years of age. This represents 17% of the total number of 8213 exercise tests. A history of myocardial infarction was present in 53% of the males and 30% of the females, while 12% of patients had previous heart surgery. Exercise was performed on a bicycle ergometer with stepwise workload increments of 10 or 20 W min-1. In 10% of patients the physician stopped the test because of serious arrhythmias or abnormal blood pressure response. The test was terminated because of fatigue (40%), angina (12%), dyspnea (18%) or tired legs and claudicatio (18%). Peak workload averaged 115 W in males and 85 W in females, which corresponds to 120% of the predicted normal values. Heart rate increased on average to 130 beats min-1 and systolic blood pressure increased to 180 mmHg. ECG changes compatible with myocardial ischaemia were observed in 42% of patients. Although elderly patients constitute a small fraction of the population referred for exercise testing, these findings indicate that the clinical value of the test when performed is similar to that in younger patients. The observation that most patients achieved higher than 'normal' maximum workloads may be due to unreliability of the reference values.
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PMID:Clinical value of exercise testing in elderly patients. 652 38

To evaluate the benefits of coronary artery bypass graft (CABG) surgery, we interviewed and tested 318 patients (268 men and 50 women) younger than age 70 before and six months after elective CABG at four university medical centers. Biomedical, psychoneurological, physical function, role function, occupational, social, family, sexual, emotional, and attitudinal variables were assessed. Quantitative comparisons showed improvement on many factors. Angina was completely relieved for 69% to 85% of persons, depending on whether it had been induced by exertion or other events. Disability days were reduced more than 80%. Seventy-five percent of employed persons had returned to work. Anxiety, depression, fatigue, and sleep problems declined. Vigor and well-being scores rose significantly. When losses were expected (eg, psychoneurological function, marital adjustment), they generally were not found. For none of the more than 60 outcome variables was widespread serious worsening found. The findings suggest that the great majority of patients are able to resume normal economic and social functioning within six months after CABG.
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PMID:Coronary artery bypass surgery. Physical, psychological, social, and economic outcomes six months later. 660 21

One hundred and twenty patients underwent a symptom limited submaximal exercise test (SSET) 8-40 days after acute myocardial infarction. No complications occurred during the exercise test. Sixty-two patients (52%) showed a normal SSET. ST-segment depression (greater than or equal to 1 mm) was detected in 21 (17.5%). Dyspnea, fatigue, inadequate blood pressure response and angina pectoris without changes in ST-segments were the end-point in 33 patients (27.5%). Furthermore, significant premature ventricular contractions occurred in four cases (3%) and limited the SSET. An SSET soon after myocardial infarction can be performed without risk. High specificity of ST-segment depression in lead V5 was confirmed by the coronary angiographic findings. Apart from ST-segment depression there were other, more frequent nonspecific end-points of SSET which require further examination regarding their prognostic value.
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PMID:[Early ergometry following acute myocardial infarction?]. 665 9

The purpose of this study was to determine whether an exercise-induced decrease in ejection fraction in patients with coronary artery disease and left ventricular dysfunction at rest represents ischemia or the nonspecific response of a compromised left ventricle to exercise stress. Accordingly, radionuclide ejection fraction responses of 246 patients with coronary artery disease and an ejection fraction at rest of less than 0.50 were compared with those of a "nonischemic" control group of 48 patients with idiopathic dilated cardiomyopathy and a similar degree of ventricular dysfunction. The significance of the ejection fraction response in the group with coronary artery disease was further examined by relating it to the angiographic extent of coronary artery disease, severity of angina, incidence of chest pain and electrocardiographic ST segment depression during exercise and long-term prognosis. The ejection fraction decreased by greater than or equal to 0.01 and greater than or equal to 0.05 during exercise in 48 and 28%, respectively, of the patients with coronary artery disease compared with only 8 and 2%, respectively, of the patients with cardiomyopathy. When exercise was limited by fatigue at a submaximal heart rate, the ejection fraction decreased in 25% of the patients with coronary artery disease but in none of the patients with cardiomyopathy. Patients with coronary artery disease whose ejection fraction decreased during exercise had a significantly higher incidence of three vessel disease, exercise-induced chest pain or ST depression and late mortality than did patients whose ejection fraction did not decrease. These relations were confirmed equally in subgroups of patients with moderate (ejection fraction 0.30 to 0.49) and severe (ejection fraction less than 0.30) left ventricular dysfunction. Thus, in patients with coronary artery disease and left ventricular dysfunction at rest, a decrease in ejection fraction during exercise is more likely to indicate ischemia than a nonspecific left ventricular response to exercise stress. In the individual patient, a decrease of 0.05 or greater, or a decrease during submaximal exercise, appears to be highly specific for ischemia. A decrease in ejection fraction identifies a subgroup of patients with a high prevalence of multivessel coronary artery disease and a high risk of death during long-term follow-up on medical therapy.
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PMID:Mechanism and significance of a decrease in ejection fraction during exercise in patients with coronary artery disease and left ventricular dysfunction at rest. 669 May 59

To investigate the cardiac determinants of treadmill performance in patients able to exercise to volitional fatigue, 88 patients with coronary heart disease free of angina pectoris were tested. The exercise tests included supine bicycle radionuclide ventriculography, thallium scintigraphy and treadmill testing with expired gas analysis. The number of abnormal Q wave locations, ejection fraction, end-diastolic volume, cardiac output, exercise-induced ST segment depression and thallium scar and ischemia scores were the cardiac variables considered. Rest and exercise ejection fractions were highly correlated to thallium scar score (r = -0.72 to -0.75, p less than 0.001), but not to maximal oxygen consumption (r = 0.19 to 0.25, p less than 0.05). Fifty-five percent of the variability in predicting treadmill time or estimated maximal oxygen consumption was explained by treadmill test-induced change in heart rate (39%), thallium ischemia score (12%) and cardiac output at rest (4%). The change in heart rate induced by the treadmill test explained only 27% of the variability in measured maximal oxygen consumption. Myocardial damage predicted ejection fraction at rest and the ability to increase heart rate with treadmill exercise appeared as an essential component of exercise capacity. Exercise capacity was only minimally affected by asymptomatic ischemia and was relatively independent of ventricular function.
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PMID:Treadmill performance and cardiac function in selected patients with coronary heart disease. 669 16

To address the hypothesis that physical conditioning may improve left ventricular function in patients with coronary artery disease, we performed first-pass radionuclide ventriculography in 53 patients at rest and during upright bicycle exercise before and after 6 to 12 months of exercise training. The peak bicycle workload achieved before the onset of fatigue, dyspnea, or angina increased by an average of 22% (p = .0001) after training, and mean heart rate at a workload equal to the pretraining maximum workload was decreased by 10 beats/min after training (p = .0002). Of 21 subjects with angina or exertional ST segment depression before training, 15 (71%) were able to exercise to the same workload without these manifestations of ischemia after training. Whereas neither mean resting left ventricular ejection fraction (LVEF) nor LVEF at peak exertion was significantly altered, mean LVEF at the pretraining maximum workload was increased from 0.50 to 0.54 (p = .002) after training. There was a significant correlation between the magnitude of training bradycardia and the increment in LVEF at the pretraining maximum workload (p = .009). We conclude that the relative bradycardia at comparable exercise workloads produced by exercise conditioning is associated with improvements in left ventricular performance as assessed by the LVEF. This observation is compatible with the hypothesis that training bradycardia in conditioned subjects with ischemic heart disease is associated with lower myocardial oxygen demand and lesser degrees of ischemia at comparable workloads. However, training effects on ventricular afterload or on ischemia contractile performance of the heart cannot be excluded.
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PMID:Effects of physical conditioning on left ventricular ejection fraction in patients with coronary artery disease. 672 12

The effect of timolol vs placebo on the frequency of anginal episodes, nitroglycerin consumption and exercise performance was investigated in a double-blind, randomized, crossover study in 23 patients with angina pectoris. The optimal dose of timolol (10-30 mg twice daily) for each patient was titrated by exercise studies. Compared with placebo, timolol decreased the weekly number of anginal attacks and the weekly number of nitroglycerin tablets consumed, reduced the resting heart rate, systolic and diastolic blood pressure, and product of systolic blood pressure times heart rate, decreased the heart rate, systolic and diastolic blood pressure, and product of systolic blood pressure times heart rate at the onset of angina pectoris or marked fatigue, prolonged exercise duration, and diminished electrocardiographic evidence of myocardial ischemia. Timolol is an excellent antianginal agent when prescribed twice daily, with the optimal dose titrated by exercise studies.
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PMID:The effect of timolol vs placebo on angina pectoris. 676 20


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