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Query: UMLS:C0015672 (fatigue)
 51,768 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Four patients had signs of primary bioprosthetic dysfunction within the fourth postoperative year after mitral valve replacement with an Ionescu-Shiley pericardial xenograft; they represent approximately 9% of patients with Ionescu-Shiley pericardial xenograft mitral valves followed up for more than 3 years at our institution. Pathological investigation showed severe incompetence of all explanted valves due to cusp tears and lacerations. Histologic study of the pericardial tissue disclosed mild to moderate collagen degeneration, without infection or calcification. Neoendothelial formation on the Dacron cloth of the sewing ring was either absent or minimal. The high incidence of valvular incompetence prompted us to try to establish a correlation between the in vivo and in vitro modes of failure of the Ionescu-Shiley pericardial xenograft. For this purpose, 10 unimplanted Ionescu-Shiley pericardial xenograft valves were tested in a fatigue test system. Severe fatigue-induced lesions occurred in this group after an average of 29.09 +/- 17.26 X 10(6) cycles; initial failure could be recognized in six of them after an average of 16.94 +/- 20.12 X 10(6) cycles. Valves tested in the fatigue test system showed tears and lacerations similar to those noted in the Ionescu-Shiley pericardial xenografts obtained from the four patients (which were assumed to have functioned for more than 100 X 10(6) cycles in each case). Correlation between results of the fatigue testing and our clinical experience enabled us to recognize four types of tears which may occur in the Ionescu-Shiley pericardial xenograft. The results of this investigation showed the following: (1) Primary tissue failure of the Ionescu-Shiley pericardial xenograft may occur suddenly. (2) A classification of tears occurring in Ionescu-Shiley pericardial xenograft valves is useful since the clinical presentation of patients may differ according to type and location of the lesion. (3) In the manufacture of pericardial valves, particular care must be observed in selection of the tissue and in the frame design. (4) Improvement of the quality control is one of the clues to enhance durability of the Ionescu-Shiley pericardial xenograft.
J Thorac Cardiovasc Surg 1984 Jun
PMID:Fatigue-induced failure of the Ionescu-Shiley pericardial xenograft in the mitral position. In vivo and in vitro correlation and a proposed classification. 672 7

Three neuropsychological tests were administered to 245 men and women, ages 25 to 69 years, before and 6 months after coronary bypass and cardiac valve operations to provide current information regarding the incidence of long-term postoperative decrements in neuropsychological function and the factors associated with them. Biographical, psychological and medical-surgical data were studied together with changes on the Trail Making Test from the Halstead-Reitan Battery, and Visual Reproduction (VR) and Logical Memory tests, both from the Wechsler Memory Scale (WMS). Although 28% of this group showed a deterioration in one or more test scores at a 9 day postoperative examination as compared to their preoperative scores, over 80% of these patients had returned to normal range by 6 months. Similarly, the majority of the 19% of patients showing a significant decrease in one or more of four scores at 6 months had incurred their performance decrements subsequent to the 9 day examination. Hence it seems inappropriate to attribute these latter dysfunctions to the surgical epidose per se, as others have reported. Only 5% of patients showed consistent postoperative test score deterioration both at 9 days and 6 months. Decrements of function at 6 months appear to be associated with total estimated blood loss greater than 3,000 ml and administration of propranolol during the operation plus several postoperative factors including higher levels of fatigue, depression, and worries related to the operation and the recovery process. These findings underscore the need for clinicians and investigators studying neuropsychological dysfunction following cardiac operations to take concurrent emotional and physical states into account, and to make repeated measures well separated in time, before interpreting the presence or absence of residual neuropsychological problems.
J Thorac Cardiovasc Surg 1982 Oct
PMID:Neuropsychological dysfunction following elective cardiac operation. II. A six-month reassessment. 698 35

In an effort to normalize the dynamic leaflet behavior of a porcine bioprosthesis, an experimental attempt was made to treat a tissue heart valve with 0.625% glutaraldehyde in the open position ("open-type valve"). Eighteen open-type valves, having fixed openings of various sizes, were examined with our pulse simulators. Eight closed-type valves, which were treated in the closed position, were studied for comparison. The results showed that closed-type valve tended to offer an immobile cusp at a low flow state; at a pump pressure of 90 mm Hg in a pulsatile flow or under steady flows of no more than 10 L/min. By contrast, the open-type valve showed the symmetric cusps opening with circular orifices at any given flow rates. Analysis of the pressure loss coefficient revealed that the leaflets prepared in the open position produced only a minimal impediment to the forward flow. One half of the anatomic orifice of a valve was considered to be the optimal size for the fixed opening. It is concluded that open position fixation is expected to provide the bioprosthesis with improved fatigue durability in patients with low cardiac output syndrome and in small children.
J Thorac Cardiovasc Surg 1982 Apr
PMID:Open versus closed position fixation of bioprosthesis. Comparative in vitro studies from the viewpoint of durability. 706 72

Nowadays all compression syndromes at the upper chest like the costoclavicular syndrome, the scalenus syndrome, the hyperabduction syndrome and the Page-von Schroetter syndrome are included under the term of thoracic-outlet-syndrome. Apart from a constitutional disposition (cervical rib, anomalies of the tendons, etc.), it needs special factors like professional activities, sports, trauma, etc. to develop a T.O.S. syndrome. The symptoms range from prickling paresthesia, early fatigue, pains in shoulder and neck, claudication like pains and strong tendency towards swelling and rest pain or peripheral gangrene. Among 3126 vascular-surgical operations 128 transaxillary rib resections were performed during the time from June 1st, 1975 until March 31st, 1980. On 105 occasions rib resection was combined with the thoracic sympathectomy. In only 4 cases the resection of a cervical rib was sufficient to obtain decompression; in 15 cases the first rib had to be resected with a cervical rib. In 3 cases direct reconstructions of the artery and subclavian vein was performed by way of transaxillary approach. Postoperatively, 56% of the patients remained completely asymptomatic, 32% were decidedly improved and 12% unchanged.
J Cardiovasc Surg (Torino)
PMID:Shoulder girdle compression syndrome. 708 41

Thirty-six patients with coronary artery disease were studied by first-pass radionuclide angiography to assess the effects of myocardial revascularization on exercise-induced myocardial ischemia. The radionuclide studies were performed in the 30 degree right anterior ablique position, at rest and during exercise, 1 to 3 days preoperatively and 10 to 14 days postoperatively. The mean population age was 53 years; the mean number of grafts placed was 4.0 per patient. Fifteen normal male volunteers were tested by rest and exercise radionuclide angiography to serve as normal control subjects. In all exercise radionuclide studies, progressive upright bicycle exercise was performed to symptoms of fatigue, dyspnea, or chest pain. The parameters of ejection fraction (EF), end-diastolic volume (EDV), and regional wall motion (RWM) were determined. Twenty-nine of the 36 patients had postoperative coronary arteriography that was correlated with radionuclide determinations. The results showed that in the normal subjects with maximal exercise the mean EF rose, the mean EDV increased 19%, and there was no exercise-induced regional wall motion dysfunction (ERWMD). In the patients with coronary artery disease prior to operation, the mean EF fell significantly, the mean EDV rose 24%, and 26 of 36 patients had ERWMD. After operation, the mean EF of the group rose, the EDV increased only 15%, and only two of 36 patients continued to show ERWMD. Of the eight patients who demonstrated on abnormal response postoperatively, seven had what was considered to be inadequate revascularization, and in one there was no explanation. The data demonstrate that myocardial revascularization does improve ventricular function by abolishing exercise-induced evidence of ischemia (decreased EF, increased EDV, and ERWMD) as assessed by radionuclide angiography. Failure to abolish the exercise-induced functional instability suggests incomplete revascularization.
J Thorac Cardiovasc Surg 1980 May
PMID:Improvement in left ventricular function after myocardial revascularization: assessment by first-pass rest and exercise nuclear angiography. 736 32

The objectives of exercise testing in congestive heart failure (CHF) may be summarized as follows: (a) detect impaired cardiac performance, (b) grade severity of cardiac failure and classify functional capability, and (c) assess effects of interventions. Several different methods are available to make these assessments, and we have to ask ourselves how well exercise testing achieves these objectives. It has to be kept in mind that the power generated by the exercising muscles is dependent on the oxygen delivery to the skeletal muscles. Oxygen uptake is the result of an integrated performance of the lungs, heart, and peripheral circulation. In patients, as well as in normal subjects, oxygen uptake is related to hemodynamic indices such as cardiac output, stroke volume, or exercise duration when a stepwise regulated maximal exercise protocol is used. However, there are major differences in the concept of a true maximum in normal subjects versus heart failure patients. Fit-normal subjects will achieve a real maximal oxygen uptake, whereas patients may stop testing before a maximum is reached because of symptoms such as dyspnea or leg fatigue. Therefore, it is better if the actual oxygen uptake can be measured. "Peak" rather than true maximal oxygen uptake has been suggested for the classification of the severity of heart failure. Peripheral factors modify the cardiac output through such factors as vascular resistance, organ function, and hormonal release. Maximal exercise will stress the cardiovascular system to a point where the weakest chain will impose a limiting effect.(ABSTRACT TRUNCATED AT 250 WORDS)
J Cardiovasc Pharmacol 1993
PMID:The role of exercise testing in heart failure. 751 35

After a single-blind, 4-week placebo run-in period, 161 patients were randomized to trandolapril 2 mg once daily (n = 54), nifedipine slow-release (SR) 20 mg twice daily (n = 55), or a combination of both drugs (n = 52) for 16 weeks. Morning predosing supine diastolic blood pressure (DBP) was the primary efficacy measurement. After 16 weeks the intention-to-treat analysis showed no significant difference in supine DBP (mean +/- SEM) between trandolapril (-12.4 +/- 1.5 mm Hg) and nifedipine SR (-15.3 +/- 1.4 mm Hg; p = 0.1). However, the combination therapy was more effective (-18.9 +/- 1.3 mm Hg). Normalized blood pressure at 16 weeks was seen with 54% on trandolapril, 63% on nifedipine SR, and 77% on the combination. Adverse events, possibly related to drug, were more common with nifedipine SR (34%) than with trandolapril (17%; p < 0.05), and in comparison with the combination (21%). Drug-related treatment emergent events, reported by more than 3% of patients (fatigue, palpitations, edema, migraine), were seen only in the nifedipine SR and combination groups. Trandolapril 2 mg proved a well-tolerated and effective antihypertensive agent, comparable to nifedipine SR 40 mg. Furthermore, the combination of the two drugs was shown to enhance the antihypertensive effect of the two compounds alone. Adverse events were less common with trandolapril and the combination than with nifedipine SR alone.
J Cardiovasc Pharmacol 1994
PMID:Comparison of the efficacy and safety of trandolapril and nifedipine SR in mild-to-moderate hypertension. Investigator Study Group. 752 8

Although essential hypertension is usually defined as a hemodynamic disorder, it is expressed differently among individuals and varies during progression of the disease state. Therefore, various types of treatment can be envisioned. The use of selective I1-imidazoline-receptor agonists to modulate I1-imidazoline receptors involved in the central regulation of blood pressure has led to the introduction of a novel class of centrally acting antihypertensive drugs. Moxonidine, a representative molecule of this class, dissociates between a 10% alpha 2-adrenoceptor-agonist action linked with side effects such as fatigue or dry mouth, and a 90% specific antihypertensive action resulting from its selective agonistic action at I1-imidazoline receptors. Clinical experience is based on more than 2,000 patients and volunteers, and long-term efficacy has been demonstrated in about 500 patients who received a daily dose of moxonidine 0.2-0.4 mg. Moxonidine produces a pronounced reduction in peripheral vascular resistance without reflex tachycardia, accompanied by reduced plasma norepinephrine concentration and plasma-renin activity. Cardiovascular responses to exercise and standing remain nearly normal, and serious or life-threatening side effects, particularly the sympathetic overactivity that can occur on sudden withdrawal of other centrally acting agents, are never observed. In addition, moxonidine behaves neutrally with respect to plasma levels of cholesterol, potassium and glucose, glucose and lipid metabolism, and renal function, and can be administered without complication to patients with asthma or certain other diseases. Studies with magnetic resonance imaging have shown that moxonidine significantly reduces left ventricular mass, an indicator of left ventricular hypertrophy (LVH), within a 6-month treatment period, an effect that coincided with decreased plasma concentrations of catecholamines and renin. Comparisons between moxonidine and other well-established antihypertensive drugs such as nifedipine, atenolol, or angiotensin-converting enzyme inhibitors showed equal effectiveness in lowering blood pressure, whereas the adverse events profile always favored moxonidine. Considering its efficacy, safety, and specific effects (e.g., its ability to reduce LVH), moxonidine meets the criteria satisfied by other currently prescribed antihypertensive drugs. Because of its especially favorable benefit-to-risk ratio, moxonidine should be recommended as first-line treatment of hypertension and may also be useful in treating related problems such as LVH, coronary artery disease, and ventricular premature beats.
J Cardiovasc Pharmacol 1994
PMID:I1-imidazoline-receptor agonists in the treatment of hypertension: an appraisal of clinical experience. 753 26

Patients with chronic heart failure (CHF) experience significant morbidity because of dyspnea and fatigue with activities of daily living. Although central hemodynamic abnormalities are the hallmark of this disorder, investigators have not shown a relationship between left ventricular ejection fraction or exercise pulmonary capillary wedge pressure and exercise intolerance in this disorder. Recent studies have focused on the contributions of pulmonary abnormalities and alterations in peripheral vasomotor control and skeletal muscle in exercise intolerance in this disorder. Early anaerobic metabolism occurs in patients with CHF and appears to be caused by a combination of reduced skeletal muscle blood flow and decreased aerobic enzyme content in skeletal muscle. Atrophy in skeletal muscle and alterations in skeletal muscle fiber typing are accompanied by alterations in contractile function in skeletal muscle. These results suggest that exercise intolerance in patients with CHF is multifactorial, and that research efforts must consider central hemodynamic abnormalities, pulmonary abnormalities, and alterations in peripheral blood flow and skeletal muscle biochemistry and histology. The present review will explore current research in this area and develop a model for understanding exercise intolerance in CHF.
Prog Cardiovasc Dis
PMID:Exercise intolerance in patients with chronic heart failure. 763 Oct 18

The efficacy and safety of cilazapril in chronic heart failure have been extensively investigated in an international clinical program in patients with underlying chronic heart failure with ischemic heart disease or dilated cardiomyopathy. Cilazapril in single doses of 1.25-5 mg produced a significant dose-dependent reduction in pulmonary capillary wedge pressure and systemic vascular resistance and a significant increase in cardiac index. In placebo-controlled studies, 1-5 mg of cilazapril once daily for 12 weeks prolonged predose exercise test duration and improved New York Heart Association classification status and signs and symptoms of chronic heart failure, including paroxysmal nocturnal dyspnea. Up to 86% of patients receiving these dosages had improvement, with only 12% of patients requiring the higher dose, 5 mg. These data indicate that cilazapril is effective when administered once daily to patients with chronic heart failure receiving concomitant therapy with digitalis and/or a diuretic. The safety of cilazapril in patients with chronic heart failure has been evaluated in 1,163 patients administered from 0.5 to 15 mg once daily for treatment periods ranging from 1 day to 57 months. Cilazapril was administered to 500 patients for at least 6 months, 264 patients for at least 1 year, and 101 patients for at least 2 years. The most frequently occurring adverse events were dizziness, coughing, dyspnea, fatigue, angina pectoris, and headache. Cilazapril was equally well tolerated by young and elderly patients. Treatment was discontinued due to adverse events in 12.9% of patients, mainly as a result of coughing (1.7%) and dizziness (1%). Forty-four patients (3.8%) died during cilazapril therapy or during a period without treatment. Of these deaths, 93% were due to cardiac causes, especially rhythm disturbances.(ABSTRACT TRUNCATED AT 250 WORDS)
J Cardiovasc Pharmacol 1994
PMID:Heart failure therapy with cilazapril: an overview. 770 63


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