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Query: UMLS:C0018799 (heart disease)
 34,133 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

One of the leading causes of mortality in diabetics is myocardial disease. In the past few years this subject has generated a significant amount of interest with the result that myocardial problems associated with diabetes are far better understood. Though originally thought to occur as a result of atherosclerosis, various studies have shown that heart disease can occur in the absence of atherosclerosis, suggesting a diabetic cardiomyopathy. Using diabetic animals, it has been possible to characterize diabetes-induced myocardial abnormalities. Diabetic rat hearts do not respond to conditions of high stress as well as controls. The functional depression is accompanied by altered cardiac enzyme systems. A decrease in myosin ATPase activity which appears to be a result of diabetes-induced hypothyroidism is seen. Also, a depression of sarcoplasmic reticular calcium ATPase, along with a depression of calcium uptake by the SR, is seen in diabetic rat hearts. Na+, K+ ATPase activity has also been shown to be depressed and the depression appears to correlate with depressed atrial contractility. High levels of circulating fats in diabetics may alter the integrity of membranes leading to altered enzyme activities. Insulin treatment has been relatively successful at reversing or preventing myocardial changes in the diabetic rat. Other treatments that have been studied include thyroid hormone treatment, since the depression of myosin ATPase can be corrected by such treatment; and carnitine treatment, as the elevation of long chain acyl carnitines (LCAC) and the resulting depression of calcium uptake in the SR can be so normalized. These treatments have not been successful at normalizing cardiac function. A combination of the two treatments normalized function only partially, suggesting that factors besides myosin ATPase and SR calcium uptake are involved. Other treatments that have been tried include vanadate, methyl palmoxirate, and choline and methionine. Vanadate treatment has proved to be encouraging in that it normalizes both function and hyperglycemia. Methyl palmoxirate, a fatty acid analog, normalized only the elevation of LCAC but did not affect function. Methionine and choline were only partially successful in preventing the functional alterations of diabetic rat hearts. The purpose of the present article is to review our understanding of diabetes-induced myocardial problems and their possible causes. Findings from our laboratory and others are described in which attempts have been made to normalize cardiac function.
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PMID:Diabetes-induced abnormalities in the myocardium. 293 41

We investigated a large Old Colony (Chortitza) Mennonite kindred with branches across Canada. Six generations of the kindred were traced. There was intermarriage among numerous family members. Insulin-dependent diabetes mellitus (IDDM) was identified in 10 members; all 7 living patients were found to carry the immunogenetic marker HLA-DR4. Nine other close relatives had disorders of carbohydrate metabolism, including gestational diabetes mellitus and non-insulin-dependent diabetes mellitus progressing to insulin use. Ten other relatives had autoimmune diseases, including rheumatoid arthritis, hyperthyroidism, hypothyroidism and multiple sclerosis. Cases of Alport's syndrome, congenital malformations, inborn errors of metabolism and unusual malignant diseases were also found in the kindred. In the small Alberta community in which the kindred was ascertained there were people of Old Colony Mennonite descent with genetic conditions such as Gilles de la Tourette's syndrome and congenital malformations, including congenital heart disease. This kindred represents the largest reported familial aggregation of IDDM. This disease and other disorders of carbohydrate metabolism occur in the context of a strong familial predisposition to autoimmune disease. Study of this family may permit empiric testing of proposed models of inheritance of diseases of complex origin such as IDDM. We report this Old Colony (Chortitza) Mennonite community because it is one of the settlements populated by this religious and genetic isolate, which extends across Canada and Central and South America and affords opportunities for the study of both common and rare inherited diseases.
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PMID:Unusual clustering of diseases in a Canadian Old Colony (Chortitza) Mennonite kindred and community. 337 May 69

Thyroid function alterations induced by amiodarone treatment (200-400 mg/day for 5 days/week) were studied in 50 patients with heart disease (age 34-75 years, mean age 55.5 +/- 11.8) for 25.6 +/- 15.0 months. Statistical analysis was made of the results obtained from the 14 patients who underwent all of the schedule examinations during the same 16-month period. A reduction in T3 was observed after 7 days' treatment; this became statistically significant at 12 and 16 months. FT3 fell significantly only after 7 days; rT3 showed an opposite trend to that of T3 (low T3 syndrome), with significant increases at all observation times. TSH rose at 7 days, then fell gradually to below baseline values after 12 months. No evidence of clinical hyperthyroidism accompanied the significant increases of T4 and FT4 observed at 1, 3, 6, and 16 months; when this complication occurred (in 6% of the cases) it was associated with a rise or lack of reduction in T3 levels. In these cases treatment was withdrawn. Amiodarone was also discontinued in 2 other cases (4%) with elevated thyroid function indices but without clinical symptoms. Seven patients who showed an isolated increase of FT3 were carefully monitored; only in one case did clinical hyperthyroidism develop with a simultaneous rise in the T3 level. A diagnosis of hypothyroidism may be considered only if there is a reduction in T4 levels, since an isolated increase in TSH is not as reliable; treatment had to be suspended for this reason in 2 cases (4%), both without clinical symptoms.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Alterations in thyroid function induced by chronic administration of amiodarone. 359 42

The concept of hypothyroid heart disease remains controversial. Although hemodynamic abnormalities have been described, the presence of underlying abnormal cardiac structures has not been confirmed. The authors studied 20 hypothyroid patients using M-mode echocardiography before and after l-thyroxine therapy. Fifteen additional hypothyroid patients were studied using two-dimensional echocardiography to confirm the data of the first study. The findings were the same in both studies: during hypothyroidism, the interventricular septum is thickened, the ratio of septal thickness to left ventricular posterior wall thickening is increased, the right ventricular wall is thickened, regional wall motion of interventricular septum and right ventricular wall is decreased, and global function of the left ventricle is decreased. These findings are reversed with l-thyroxine therapy; they occur within 6 months of the development of hypothyroidism, but appear unrelated to elevated TSH levels. Whether the thickened interventricular septum and right ventricular wall represent true muscular hypertrophy requires further elucidation. Nevertheless, these data demonstrate the existence of a hypothyroid cardiomyopathy.
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PMID:Hypothyroid cardiomyopathy: echocardiographic documentation of reversibility. 360 87

In earlier studies using papillary muscles of the rat left ventricle and highly sensitive thermopiles we demonstrated that the heat liberated per gram of myocardium per unit of developed tension-time integral is decreased when the rats suffered from hypothyroidism or renal hypertension. This increase in economy of force production was shown to be associated with a decrease in myosin-ATPase activity and a change in isomyosin composition. In a recent study we showed an increase in heat per gram of mammalian myocardium per tension-time integral of 70% after application of isoproterenol. In order to study the relationship between energy costs and developed tension-time integral in the human heart, haemodynamics and myocardial oxygen consumption were measured. The data were obtained using a Millar microtip catheter pressure transducer and the argon method. Haemodynamics and myocardial energetics were analysed in 8 patients without significant heart disease before and after application of isoproterenol and in 10 patients with dilative cardiomyopathy (NYHA II-III). During one cardiac cycle, myocardial oxygen consumption per gram of LV myocardium per beat (MVO2/g x beat) is related to LV stress-time integral (integral of sigma xt). The economy of myocardial contraction (EC) was calculated by (formula; see text) EC was 11.3 +/- 3.2 in normal and 14.3 +/- 4.7 dyn x s x g/cm2 x mu cal in dilative cardiomyopathic hearts (NS). Isoproterenol decreased EC from 11.3 +/- 3.2 to 5.5 +/- 1.6 dyn x s x g/cm2 x mu cal in the normal hearts (p less than 0.01). In the rat myocardium, changes in economy of force generation were found due to catecholamines, pressure overload and hypothyroidism. In the human heart, similar energetic changes were observed due to catecholamines. No significant differences in energy of force production were seen between normal and dilative cardiomyopathic hearts. The effect of catecholamines in the mammalian and human myocardium is explained by changes in activation processes and in chemomechanical energy transduction at the level of the contractile proteins.
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PMID:Acute and chronic changes of myocardial energetics in the mammalian and human heart. 366 28

Seven of the 34 infants identified through the Welsh Hypothyroid Screening Programme have additional congenital abnormalities. Two infants have a previously undescribed syndrome, two have chromosomal abnormalities, two have congenital heart disease, and one has a myelomeningocoele. Congenital hypothyroidism often seems to be associated with other congenital abnormalities.
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PMID:Congenital anomalies associated with hypothyroidism. 372 32

Clinical and laboratory features of 99 patients receiving long-term amiodarone therapy were analyzed to determine which individuals may be at a high risk for developing amiodarone-induced thyroid dysfunction. The group of 68 men and 31 women was followed up for an average of 27 months (range 3 to 60). There were no differences in age, sex, dose of amiodarone, type or severity of underlying heart disease or baseline serum thyroxine levels in patients who developed hypothyroidism (n = 32) or hyperthyroidism (n = 5) or remained euthyroid (n = 62). Baseline serum thyrotropin levels were statistically higher in patients who became hypothyroid, but there was considerable overlap with the other patient groups. Serum reverse triiodothyronine (reverse T3), which has been suggested to be a marker of amiodarone efficacy, correlated directly with serum thyroxine levels, and was not an independent variable. There was no pattern to the time course for development of thyroid dysfunction, which occurred in 49% of those followed up and developed as early as 1 month or, in one individual, as late as after 3 years of amiodarone therapy. There are few guidelines for replacement therapy in patients with amiodarone-induced hypothyroidism. L-thyroxine dosage was adjusted cautiously in these high risk individuals to achieve serum thyroxine levels within the reference range of euthyroid individuals taking amiodarone: the mean dosage required was 136 micrograms/day. Normalization of serum thyrotropin (TSH) would have required doses of L-thyroxine that were judged to be excessively high.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Thyroid dysfunction during chronic amiodarone therapy. 379 94

A review of factors altering the safety margin between a therapeutic and a toxic dose of digitalis includes the consideration of: clinical conditions to which digitalis action may be undesirable, allergy and hypersensitivity to digitalis, physiologic factors modifying tolerance to digitalis, factors that change the amount of digitalis in the body, nervous and metabolic factors modifying tolerance to digitalis, modifications of digitalis tolerance produced by the status of the myocardium, and modifications of digitalis tolerance produced by diseases of other organs. The problems related to digitalis toxicity are more common than those of resistance to treatment. The most important factors contributing to decreased tolerance and risk of toxicity are: heart disease, poor renal function, hypokalemia and hypothyroidism. The roles of impaired liver function, chronic lung disease, acid-base disturbances, anesthesia, autonomic imbalance, calcium and magnesium are less important and less well established.
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PMID:Factors affecting tolerance to digitalis. 388 54

The effects of Amiodarone (1000-1400 mg/week, for a period ranging from 3 to 24 months) on thyroid gland function were studied in 45 patients with heart disease, using a new method of free thyroid hormone assay. Forty-four untreated patients and 11 normal subjects were used as controls. In treated patients the prevalence of dysthyroidism was 22,2% (15,6% hypothyroidism and 6,6% hyperthyroidism); the onset of dysthyroidism ranged from 20 days to 2 years after the beginning of treatment. In control patients the prevalence of dysthyroidism was 4,4% (2,2% hypothyroidism and 2,2% hyperthyroidism). In patients with hypothyroidism (TSH greater than 7 microunits/ml) T4 levels were generally low, while T3, fT4 and fT3 levels were normal. In treated patients with hyperthyroidism (fT3 greater than 5,3 pg/ml and fT4 greater than 16 pg/ml) T4 values were high, while T3 concentrations were in the normal range. In Amiodarone-treated euthyroid patients, mean T4, fT4 and rT3 values were significantly (p less than 0,01) higher than those of control subjects; TSH levels were normal in all the groups studied. These data suggest that Amiodarone can exert both a direct effect on the thyroid gland and the peripheral metabolism of thyroid hormones. The action on the thyroid gland is suggested by the high prevalence of dysthyroidism in Amiodarone-treated patients and by the high levels of T4 and fT4 observed in patients who did not show dysthyroidism. The action on the peripheral hormonal metabolism seems to be proved by the high levels of rT3 and by the prolongation of QTc interval.
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PMID:[Thyroid function in patients chronically treated with amiodarone]. 688 52

By echocardiographic technique the Authors have studied a rare congenital anomaly: "sub-hyoid ectopy of the thyroid gland". The patient, a 35 years unmarried woman, with manifest clinic symptoms of hypothyroidism, was affected with mesotelesystolic prolapse of the posterior leaflet of the mitral valve. It has also been possible to put in evidence the findings of mixoedematous cardiopathy and its resolution after thyroid opotherapy.
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PMID:[Congenital thyroid abnormality (subhyoid ectopy) associated with mitral valve prolapse]. 707 9


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