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Query: UMLS:C0018801 (heart failure)
 72,216 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

All hyponatremic states have in common elevation of vasopressin. Without this the loss of salt would be followed by appropriate diuresis and normonatremia. If hyponatremia is triggered by a volume change as in heart failure or portal cirrhosis not only is ADH released but the mechanisms that control salt retention create an essentially sodium free urine, always less than 20 mEq/L. If the initial event is inappropriate ADH secretion whether it be cerebral disease, neoplasm, a pulmonary lesion or a growing list of drugs; there is no related signal for salt retention and urine sodium and tonicity are high, the latter usually higher than that of plasma. If salt loss is due to intrinsic renal disease, diuretics, osmotic or otherwise, or adrenal failure urinary sodium is variable depending upon the magnitude of the response to volume of salt retaining factors. Because hyponatremia is often present with major illness and because more than one factor may be involved in its genesis, the establishment of its origin and appropriate treatment remain a diagnostic and therapeutic challenge.
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PMID:Hyponatremia: manifestations and treatment. 162 51

Although alcohol has long been known to induce cardiac depression and cardiomyopathy, it is not known whether drug therapy or pharmacologic manipulation can be used to prevent or reverse these toxicities. With this in mind, high levels (15 mM) of magnesium (Mg) were investigated for their potential antialcohol effects on perfused rat hearts. A high concentration of ethanol (135 mM) was used to induce rapid cardiac failure as assessed by hemodynamic and metabolic parameters. During ethanol perfusion in normal 1.2 mM [Mg2+]o physiologic salt solution, coronary flow decreased immediately, and all of the hemodynamic parameters studied (except for heart rate) were depressed significantly. After 10 min of 135 mM ethanol perfusion, only 60% of the hearts kept beating; at 15 min, only 42% of the hearts continued to beat. Myocardial metabolism under such conditions as assessed by examination of coronary effluent concentrations of lactic acid (LA), lactic acid dehydrogenase (LDH) and creatine phosphokinase (CPK) was rapidly and severely compromised. Although 15 mM MgSO4 alone did not alter coronary flow and systolic pressure under the conditions studied, it did decrease cardiac output, heart rate and total pressure developed. However, when 15 mM MgSO4 was given 10 min before ethanol, and continued during ethanol perfusion, the usual depression in all assessed cardiac hemodynamic parameters (except heart rate) caused by ethanol was not observed. During 15 min of high [Mg2+]o perfusion, coronary flow recovered from 19.1 +/- 6.8% (ethanol alone) to 68.1 +/- 9.9% of control values (p < 0.01); cardiac output recovered from 10.4 +/- 4.6% (ethanol alone) to 43.6 +/- 7.5% of control (p < 0.01); stroke volume went from 12.9 +/- 5.8% (ethanol alone) to 97.1 +/- 14.5% of control (p < 0.01); systolic pressure from 55.3 +/- 3.6% (ethanol alone) to 88.8 +/- 4.0% of control (p < 0.01), and total pressure developed from 23.9 +/- 7.8% (ethanol alone) to 35.0 +/- 4.5% of control (p < 0.05). Assessment of the metabolic biochemical parameters supported these changes in hemodynamic improvement. For example, LA, LDH and CPK all went from elevated values towards normal levels. There were similar hemodynamic and metabolic responses to high [Mg2+]o given during ethanol perfusion to that given before ethanol perfusion. The hemodynamic and metabolic beneficial effects between groups pretreated or treated with high [Mg2+]o exhibited no significant differences. These results suggest that high [Mg2+]o (15 mM) given either before or during ethanol-induced cardiotoxicity is effective in attenuating both functional and metabolic damage caused by high ethanol perfusion in the rat heart.
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PMID:Beneficial effects of high magnesium on alcohol-induced cardiac failure. 166 23

In contradiction earlier viewpoints, cardiac failure cannot be defined as a purely hemodynamic problem nor as only a cardiac problem. On the other hand decreased cardiac output (Co), increased filling pressure, increased wallstress and myocardial O2-consumption (MVO2) are the cause of many humoral counterregulations. Therefore, it is not always certain if the observed alterations are the causes or consequences of cardiac failure. The systemic counter-regulations will be modulated by desensitized cardiopulmonary mechanoreceptors, followed by decreased inhibition of central vasomotoric stimuli and endothelial and endocardial function, by altered signal transmission, as well as by altered gene expression within the myocytes. Depending on the degree of insufficiency, it may be attempted, by increase of the preload and of the contractility, to restore the hemodynamic basic situation. Such an attempt is based upon increased activity of the sympathetic nervous system, stimulation of the renin-angiotensin-aldosterone-system (RAAS) or the increased level of ADH. The reduced contractility and response of the myocytes, caused by the downregulation of beta 1-receptors and Gs-proteins, as well as by the upregulation of Gi-proteins, and the increased afterload with increased MVO2 and decreased CO all lead to a vicious circle. There are only some mechanisms that are directed against these regulations. The decreased response of the myocardium to endogenous catecholamines, the stimulation of ANP-secretion, as well of the prostaglandin-secretion are among the favorable regulations. They cause increase of natri- and diuresis, improved renal perfusion, vasodilatation, and inhibition of the RAAS and ADH-secretion with reduction of true thirst and craving for salt.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:[Synopsis of endocrine and hemodynamic changes in heart failure]. 179 35

The impact of treatment on prognosis of patients with chronic congestive heart failure depends not only on pharmacological therapy but also on nonpharmacological aspects of patient management. Patient compliance, life style changes, salt and fluid restriction, detailed patient information and measures of self control greatly affect therapeutic efficacy. Reasons for hospitalizations and emergency room visits: In an analysis of 82 admissions of patients for decompensated chronic congestive heart failure we found poor compliance with drug treatments or dietary instructions as causally related factors in 30 patients, uncontrolled hypertension in 22 patients, acute infection in 18 and acute myocardial ischemia in 18 patients. More than half of the patients had weight gain before decompensation, that had not been adequately answered by changes in medication. Inadequate patient information: Inadequate knowledge about necessary life style changes at the time of hospital discharge is often found in patients with chronic heart failure. Less than 50% of these patients remembered correctly the instructions on key issues of necessary life style changes and diet. Drug treatment of heart failure: Recent controlled drug trials have not gained enough weight in therapeutic decisions of physicians treating heart failure patients. While ACE-inhibitors have been shown to improve longevity in congestive heart failure only 6% of patients with heart failure are treated with these drugs, while 5% are treated with calcium antagonists which have not been proven to be of symptomatic or prognostic benefit and may be harmful as well in this disease. Inadequate dosage in patients with chronic renal failure or in elderly patients as well as inadequate choice of drugs lead to side effects in a considerable percentage of patients.
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PMID:[Effects of patient information, compliance and medical control on prognosis in chronic heart failure]. 182 Feb 95

Plasma concentrations of atrial natriuretic peptide and aldosterone and plasma renin activity were measured in patients with peripartum heart failure and in age matched healthy women post partum. Both groups had carried out traditional postpartum practices of salt consumption and body heating. Plasma concentrations (mean (SEM)) of atrial natriuretic peptide were significantly higher in the seven patients with peripartum heart failure (146.9 (24.3) pg/ml) than in the seven controls (4.4 (0.8) pg/ml). Both plasma aldosterone and plasma renin activity were suppressed in the patients with peripartum heart failure. After treatment for the heart failure plasma atrial natriuretic peptide fell considerably and there were associated increases in plasma aldosterone and plasma renin activity. The high plasma concentrations of atrial natriuretic peptide may have been a compensatory response to salt and water retention as well as to the heart failure. These high concentrations could also, in part, have suppressed the release of aldosterone and renin in an attempt to correct for volume overload.
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PMID:Atrial natriuretic peptide, aldosterone, and plasma renin activity in peripartum heart failure. 182 4

The pathophysiological role of atrial natriuretic factor in patients with chronic heart failure is still unclear. Plasma ANF levels are elevated in this condition, particularly in patients with severe left ventricular dysfunction and during acute exacerbations. Drug therapy, including diuretics, vasodilators and inotropes which reduce cardiac filling pressures also reduce plasma ANF levels. In the clinical setting the measurement of ANF levels may provide a useful means of assessing salt and water retention in patients with heart failure. Intravenous infusion of ANF to patients with heart failure causes a diuresis and natriuresis, a fall in filling pressures and possibly suppression of the renin-angiotensin aldosterone system. High bolus dosing with the peptide may reduce systemic vascular resistance resulting in hypotension, which markedly attenuates the renal effects. A new pharmacological approach in this area is the development of neutral endopeptidase inhibitors, which prolong the half-life of endogenous ANF and potentiate its effects. The therapeutic potential of ANF in heart failure has yet to be realised.
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PMID:Atrial natriuretic factor in chronic heart failure. 182 7

The potent diuretic and natriuretic properties of atrial natriuretic factor (ANF) suggest that atrial hormones may participate to the regulation of salt and water excretion under physiological conditions. ANF, via the increase of its intracellular second messenger cGMP, has been recently shown to inhibit the apical sodium channel of the inner medullary collecting tubule (IMCD). In addition, ANF inhibits renin and aldosterone synthesis and antagonizes the antinatriuretic effects of angiotensin II. ANF may also contribute to the excretion of free water by inhibiting both the secretion of vasopressin and its antidiuretic action. ANF appears to play an important physiological role in sodium repleted states, or when the effective plasma volume is increased. On the contrary, when the effective plasma volume is decreased or in sodium depleted states, the natriuretic effect of both endogenous and exogenous ANF is severely blunted. That ANF-resistance may be related to the activation of the renin-angiotensin-aldosterone axis, increased circulating catecholamines, renal sympathetic nerve stimulation, changes in renal hemodynamics or increased degradation of ANF. All these factors could explain the lack of significant natriuretic effect of both endogenous and exogenous ANF in some pathological conditions such as heart failure or liver cirrhosis. ANF may also been concerned in water homeostasis. In addition to the well-known osmoregulatory pathways of water metabolism, we recently found that ANF could be involved in the volume adjustment to acute water intake in normal man.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Atrial natriuretic factor and the endocrine control of electrolyte homeostasis. 183 42

The aim of this study was to highlight a different hormonal and hemodynamic pattern in patients with mild cardiomyopathy. For this purpose, we studied subjects with mild heart failure (CHF; NYHA class I and II; post-ischemic and idiopathic) who underwent an isotonic saline load (SL) (0.22 ml/kg/min of 0.9% NaCl for 120 min). A second group of age- and sex-matched normal subjects (C) was studied as a control. Basal hormonal and hemodynamic values of the 2 groups differed only in atrial natriuretic factor (ANF), left ventricular end-diastolic diameter and ejection fraction (EF). There were, on the contrary, no differences in basal plasma renin activity (PRA) and plasma aldosterone (PA) values. After SL, in C, percent changes in EF, cardiac output and ANF values were significantly higher than in CHF while total peripheral resistances increased only in CHF but not in C. In both groups there were decrements of PRA and PA, but these responses were significantly higher in C than in CHF. In conclusion, our results show that hormonal, renal and hemodynamic responses to salt/volume load are compromised in the early asymptomatic phase of heart failure. These abnormalities may predict the progressive deterioration of cardiac function, and may indicate appropriate therapeutic interventions since the early phases of the disease.
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PMID:[The early hemodynamic and hormonal changes in patients with left ventricular dysfunction]. 183 21

The pathogenesis of essential hypertension may possibly involve a deficiency in, or a decreased response to, endogenous vasodilator and natriuretic factor(s). Searching for hereditary or familial defects, it is plausible to evaluate blood pressure (BP) regulating factors in (yet) normotensive offspring of hypertensive parents (OHyp), some of whom are in fact in a stage of prehypertension. Studies by our group demonstrated that compared with healthy offspring of normotensive parents, OHyp have plasma atrial natriuretic (ANF) factor levels that are unaltered on a low salt intake but often fail to increase normally in response to a high salt intake. Plasma levels of cyclic GMP, the presumed second messenger of ANF, also may tend to be decreased in certain OHyp. On the other hand, renal excretory responses of cyclic GMP and electrolytes to ANF infused in "physiological" dose were unchanged in some OHyp tested so far. In borderline to moderate, uncomplicated essential hypertension, plasma ANF levels are often "normal." This may be inappropriately low relative to the existing BP, although the relationship of circulating ANF to atrial pressures in essential hypertension remains to be clarified. A conversion to higher plasma ANF values may occur with cardiac complications such as left ventricular hypertrophy, enlargement, dysfunction, or overt heart failure. Acute or short-term elevation of circulating ANF within the physiological and pathophysiological range by ANF infusion produces an exaggerated natriuresis and lowers BP in essential hypertensive patients. We postulate a syndrome of ANF deficiency, characterized by an impaired response of circulating ANF to high salt intake and by low cyclic GMP levels in certain yet normotensive offspring of essential hypertensive parents and by inappropriately "normal" plasma ANF in some patients with uncomplicated essential hypertension. At the stage of prehypertension, a disturbance in the ANF - cyclic GMP pathway may be expressed primarily at the circulatory rather than at the renal level. Hypertension-prone humans also tend to have an exaggerated vascular reactivity to norepinephrine. Whether the two disturbances may be interrelated is presently unknown. Both defects may potentially predispose to the development of essential hypertension. Relative ANF deficiency, an enhanced natriuretic response to ANF, and a sustained antihypertensive effect of infused ANF may represent a rational basis for treatment of essential hypertension with agents that activate the ANF system.
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PMID:Developing essential hypertension: a syndrome involving ANF deficiency? 183 26

Previous studies strongly suggest that adenosine receptors on juxtaglomerular cells function to restrain the secretion of renin induced by a variety of stimuli. The clinical significance of this is that caffeine, a widely consumed adenosine receptor antagonist, could augment renin release responses to diseases such as renovascular hypertension, liver cirrhosis and heart failure and to therapeutic maneuvers such as salt restriction, diuretics and vasodilators. Caffeine may be particularly troublesome in this regard because this methylxanthine has central nervous system effects and intracellular actions that also might contribute to the overall ability of caffeine to potentiate renin secretion. The purpose of this study was to document the effects of caffeine on renin release responses to a vasodilator and to investigate what mechanisms were responsible for any augmentation of vasodilator-induced renin secretion. Accordingly, we compared the effects of caffeine vs. 1,3-dipropyl-8-p-sulfophenylxanthine (DPSPX; a xanthine that we documented in this study not to significantly enter the brain or penetrate cell membranes) on base-line and hydralazine-induced renin release in both normal and beta adrenoceptor-blocked (propranolol, 15 mg/kg) rats. Both xanthines (at a dose of 10 mg/kg plus 150 micrograms/min) attenuated adenosine-mediated hypotension and bradycardia, and DPSPX was at least as effective as caffeine in antagonizing peripheral adenosine receptors. Caffeine and DPSPX increased base-line plasma renin activity to a similar extent regardless of whether the animals were pretreated with propranolol. In rats with an intact beta adrenergic system, caffeine, but not DPSPX, increased the renin release response to low-dose hydralazine (1 mg/kg). Although both xanthines augmented the renin release response to high-dose hydralazine (10 mg/kg), caffeine was more efficacious in this regard. In beta adrenoceptor-blocked rats, neither caffeine nor DPSPX augmented the renin release response to low-dose hydralazine, whereas both xanthines equally potentiated the renin release response to high-dose hydralazine. These data demonstrate that caffeine increases base-line renin release primarily by blocking peripheral (most likely renal), cell-surface adenosine receptors; however, caffeine potentiates vasodilator-induced renin secretion in part by blocking peripheral (most likely renal), cell-surface adenosine receptors and in part by additional central nervous system and/or intracellular mechanism(s) that involve the beta adrenergic system.
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PMID:Caffeine potentiates vasodilator-induced renin release. 200 84


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