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

The high prevalence and poor prognosis of heart failure are a major concern. Hospitalization for heart failure accounts for a major proportion of health-care expenditure. A number of large clinical trials have been initiated to assess therapeutic strategies to improve prognosis for patients with this condition. Results from one of the largest and most recently completed of such studies, the Studies of Left Ventricular Dysfunction (SOLVD) trial, demonstrate that addition of the long-acting angiotensin-converting enzyme (ACE) inhibitor, enalapril to conventional therapy with diuretics and digoxin is associated with reduced rates of mortality and hospitalization for heart failure. Activation of the renin-angiotensin-aldosterone system (RAAS) appears to play an important role in the pathogenesis of this condition. The effects of treatment with this ACE inhibitor may be related to the degree of RAAS suppression it affords.
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PMID:Therapeutic interventions to reduce rates of hospitalization and death in patients with heart failure: new clinical evidence. 147 52

Pathophysiological mechanisms are reviewed concerning the onset and the perpetuation of the clinical features of congestive heart failure. This syndrome is a severe condition of poor prognosis and bad life quality which in the last decades has reached, in the western industrial countries, the highest levels of general mortality, mainly due to the high prevalence of hypertensive and ischaemic myocardiopathies in the last years. To the clinical features of heart failure mainly contributes a deregulation of the physiological compensatory mechanisms contemporarily and concurrently activated following the primary deficiency of the heart pump function. In physiological conditions, following the myogenic adapting mechanisms reflex mechanisms intervene, activated by intracardiac and aortic and carotid-sinus mechanoreceptors following the variations in intracardiac and intravascular pressure and generally evoking negative feed-back effects. In patients with heart failure arterial high pressure mechanoreceptors respond to the reduction in effective arterial pressure thus provoking a deactivation of the tonic inhibition on the sympathetic cardiovascular drive. This leads to an activation of peripheral and renal vasoconstrictor tone, to a raised medullary catecholamine incretion, to heart rate and inotropism stimulation, and to an increase in pituitary gland ADH production as well as to an activation of renin-angiotensin-aldosterone system (RAAS). Analogous vasoconstrictive, and sodium and water retentive effects can be elicited by endothelin produced by endothelial cells and found in high plasma levels in CHF. These excitatory effects, leading to a rise in systemic vascular resistance and to hydro-electrolytic retention with volume expansion, are not efficiently counteracted by the opposite effects triggered by cardiopulmonary vagally mediated mechanoreceptors activated by the raised cardiac filling pressure and leading to sympathetic nervous inhibition, peripheral and renal vasodilation, ADH and RAAS inhibition. Analogous effects should be provoked by the raised production, due to enhanced heart wall distension, of atrial natriuretic factor leading to vasodilation, natriuresis and diuresis. Reduced sensitivity of cardiopulmonary baroreceptors and lowered production of ANF due to structural cardiac changes could represent, according to most opinions, the main factors responsible for the prevailing sympathetic activation and hydro-saline retention in CHF. The activation of cardiopulmonary sympathetic positive-feed back afferents, could be also involved in the characteristic alteration of the vago-sympathetic balance in heart failure. The persistent reduction in heart pump function could lead to the instauration of vicious circles among the various regulatory systems and create an overcompensation condition.(ABSTRACT TRUNCATED AT 400 WORDS)
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PMID:[The physiopathological aspects and new therapeutic approaches in cardiac-circulatory failure]. 149 59

Electrolyte abnormalities are a frequent and potentially hazardous complication in patients with heart failure. This may be due to the pathophysiological alterations seen in the heart failure state leading to neurohumoral activation (stimulation of the renin-angiotensin-aldosterone system, sympathoadrenergic stimulation), and due to the complications of therapy with diuretics, cardiac glycosides or ACE inhibitors. Patients with heart failure may exhibit hyponatremia due to a decrease in water excretion, which may be related to the enhanced release of both angiotensin and vasopressin and can be exaggerated by diuretic therapy. Along with potassium and calcium, magnesium influences cardiovascular function. Magnesium and potassium deficiencies play an important role in the development of cardiac arrhythmias. Magnesium is essential for the maintenance of intracellular potassium concentration. Although there are conflicting data regarding the prevalence of hypomagnesemia in patients with chronic heart failure (the values range from 7-37%), multiple studies have documented lower magnesium concentrations in patients with heart failure than in normal controls. As magnesium and potassium are mainly intracellular ions, measurements in serum or plasma are of limited value to assess magnesium status. There was no correlation between the intracellular electrolyte content and the electrolyte levels in plasma, either for mononuclear cells or erythrocytes or for myocardial and skeletal muscle. Loop diuretics (e.g. furosemide) are supposed to cause a substantial loss of both magnesium and potassium in the plasma and intracellular space. The potassium-sparing diuretics amiloride and triamterene are reported to also exert magnesium-sparing effects. Recently, ACE inhibitors have been documented to have important magnesium-conserving actions, possibly via their effect on glomerular filtration. Hyperkalemia, secondary to the use of ACE inhibitors in patients with heart failure, is well documented. Digoxin directly limits the renal tubular reabsorption of magnesium, therefore increasing magnesium excretion. Low magnesium and potassium concentrations increase cardiac glycoside toxicity. In contrast, elevated levels of magnesium decrease the sensitivity of human myocardium to antiarrhythmogenic actions of cardiac glycosides, without affecting maximally developed tension. Moreover, magnesium increases binding affinity of cardiac glycosides to the receptor. The antiarrhythmic action of magnesium is suspected to be mediated by a reduced sensitivity to electrophysiological changes induced by Ca2+, thus indicating Ca2+ antagonistic properties of magnesium. Magnesium deficiency has also been implicated in sudden death, notably in patients with congestive heart failure. Therefore, when treating congestive heart failure, one must consider how to prevent depletion of electrolytes or how to replete potassium and magnesium in deficiency states.
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PMID:Heart failure and electrolyte disturbances. 150 35

For intracranial diseases, plasma atrial natriuretic peptide (ANP), antidiuretic hormone (ADH) and aldosterone were determined and their effects on the development of hyponatremia with central origin were studied. The subjects were 71 cases of intracranial diseases which were admitted to our hospital during a period of 1 year from March, 1989 to March, 1990. The diseases were broken down to subarachnoid hemorrhage 26 cases, hypertensive intracerebral hemorrhage 19 cases, head injury 12 cases, cerebral infarction 11 cases and 3 other cases. Serum-urine electrolytes, plasma ANP and ADH were determined in the acute stage on Day 1 to 4, in the hyponatremia stage on Day 5 to 14 and in the chronic stage on Day 15 downward. Hyponatremia was defined as the serum sodium level of 130 mEq/l or less. Cases evidently having other causes such as heart failure and renal insufficiency were excluded. In the normal control group of persons who were admitted to our hospital for a close checkup (n = 20), plasma ANP was 26.5 +/- 11.6 pg/ml (10-50); levels of 50 pg/ml or more were regarded as abnormally high. 1) Hyponatremia was found in 18 cases (25.4%), subarachnoid hemorrhage in 7 cases, hypertensive intracerebral hemorrhage in 4 cases, head injury in 5 cases and others in 2 cases. 2) The time of onset of hyponatremia was on the 8.3 hospital day. The duration was 7.2 days. The minimum serum sodium level was 124.6 mEq/l. 3) There was no significant change in the plasma aldosterone level at each stage.2+ Predicting development of hyponatremia from plasma ADH and ANP levels in the acute stage is difficult. Inadequate secretion of ANP rather than ADH appeared to be an important factor for the development of hyponatremia, but the plasma ANP level was not always abnormally high, so involvement of other sodium diuretic factors should also be kept in mind.
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PMID:[A study of plasma atrial natriuretic peptide, antidiuretic hormone and aldosterone levels in a series of patients with intracranial disease and hyponatremia]. 153 80

In recent years, captopril has attracted considerable clinical attention as an agent for use in treating heart failure. We administered 15 mg/kg of captopril or 1.5 mg/kg of enalapril to 5-week-old J-2-N cardiomyopathic hamsters for 10 or 15 weeks, and investigated the roles of the renin-angiotensin-aldosterone and kallikrein-kinin systems in the onset and progress of cardiomyopathy. In the untreated group, serum creatine kinase levels increased in accordance with the progression of cardiomyopathy, but this increase was markedly inhibited by the administration of captopril. The rise in serum aldolase levels was similarly inhibited. Serum malondialdehyde levels were significantly reduced by the administration of captopril. ECG findings and the ventricular myosin isoenzyme pattern were also markedly improved by captopril. The improvement in all these parameters was less with enalapril. These differences between captopril and enalapril suggest that increases in tissue bradykinin and vasodilatory prostaglandins may play an important role in the beneficial effects of captopril.
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PMID:The effects of angiotensin converting enzyme inhibitors and the role of the renin-angiotensin-aldosterone system in J-2-N cardiomyopathic hamsters. 153 90

We have previously demonstrated that baroreceptor discharge sensitivity is depressed in dogs with experimental heart failure and that this depressed sensitivity can be reversed by the Na+,K(+)-ATPase inhibitor ouabain. This suggests that enhanced Na+,K(+)-ATPase activity in baroreceptors is responsible for the blunted baroreceptor discharge sensitivity seen in heart failure state. Because aldosterone, a known stimulator of Na+,K(+)-ATPase, is elevated in heart failure the present study was undertaken to determine the effects on baroreceptor discharge of perfusion of the carotid sinus with aldosterone in normotensive dogs. Single unit baroreceptor activity was recorded as well as carotid sinus pressure and the diameter of the carotid sinus. Perfusion of the carotid sinus with aldosterone (in Krebs-Henseleit solution) significantly elevated threshold pressure (108.5 +/- 3.1 mm Hg versus 92.7 +/- 4.6 mm Hg, p less than 0.05) and reduced peak discharge rate (40.3 +/- 3.9 spikes/sec, p less than 0.05). These effects appeared 15 minutes after aldosterone perfusion and remained constant for the next 60 minutes. There was no change in the carotid sinus pressure-diameter curve during perfusion with aldosterone. Perfusion of the carotid sinus with ouabain (0.1 microgram/ml) during aldosterone perfusion did not reverse the blunted baroreceptor discharge. The blunted baroreceptor activity induced by perfusion of the carotid sinus with aldosterone was prevented by removal of the endothelial cells in the carotid sinus area with a balloon-tipped catheter or by perfusion with saponin. Finally, perfusion of the carotid sinus with spironolactone (10 ng/ml), a mineralocorticoid receptor antagonist, prevented the inhibitory effect of aldosterone. These data suggest that aldosterone reduces maximum baroreceptor discharge.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Aldosterone reduces baroreceptor discharge in the dog. 154 52

The clinical efficacy of enalapril was investigated in 21 patients with severe heart failure. For each subject, the following parameters were compared before and one month after enalapril maintenance treatment. NYHA functional class, Killip's class, cardiothoracic ratio (CTR), left ventricular (LV) function estimated by echocardiography and gated equilibrium radionuclide angiography, Holter ECG recordings, serum digoxin concentration (SDC), plasma remin activity, plasma aldosterone concentration, plasma norepinephrine concentration (PNE), etc. Short- and long-term hemodynamic responses to enalapril were also studied, with simultaneous measurement of enalapril concentration by radioimmunoassay. After maintenance therapy, patients showed a significant improvement as judged by NYHA functional class, Killip's class, and CTR. The LV fractional shortening and the ejection fraction significantly increased. The frequency of ventricular tachycardia showed a significant tendency to decrease after the therapy. The SDCs were unchanged, which indicates no pharmacokinetic drug interaction between digoxin and enalapril. Hemodynamic assessment showed a reduction in systemic vascular resistance, a reduction in mean blood pressure, and an increase in the cardiac index. No major side effects were observed during the study period. According to a multivariate analysis, the coefficient of determination of PNE was the highest for the final global improvement rating. This may reflect the neurohormonal improvement of congestive heart failure by enalapril therapy. In conclusion, enalapril is recommended for treating patients with severe CHF.
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PMID:Clinical studies of enalapril treatment for patients with severe congestive heart failure. 153 75

Scorpion envenomation is a common medical problem and life hazard in many countries of the world. Scientific investigations have addressed the interrelationship between the stimulatory effects of the venom on the autonomic nervous system and adrenals and the subsequent effects of released transmitters on the cardiovascular system. A number of clinical cardiovascular syndromes may dominate the initial clinical presentation after envenomation: the syndromes usually vary with the age of the victim, the size of the offender and the season. Central nervous system dysfunction is seen in children but rarely observed in adults; if accompanied by severe hypertension the clinical picture is consistent with acute hypertensive encephalopathy. Heart failure, pulmonary edema or a shock-like syndrome has been observed in 25% and hypertension in 30% to 77% of our patients. The electrocardiographic abnormalities recorded in the majority of the patients after envenomation include an "acute myocardial infarction-like pattern." Rhythm disturbances are frequent but conduction abnormalities are rare. Echocardiographic, radionuclide and experimental hemodynamic observations have provided evidence that heart failure and pulmonary edema after envenomation are multifactorial with diminished systolic performance following the initially increased left ventricular contractility and decreased ventricular diastolic compliance. Clinical laboratory data reporting increased catecholamine metabolite excretion and elevated plasma renin and aldosterone are consistent with the stimulatory effects of the venom on the autonomic nervous system. Treatment, including our experience with vasodilators and calcium channel blockers, is reviewed.
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PMID:The cardiovascular system after scorpion envenomation. A review. 158 74

The diuretic and natriuretic response to an intravenous dose of frusemide 40 mg was assessed in the erect and supine positions in 10 patients with cardiac failure who were being treated with enalapril 10 mg twice daily in addition to diuretics (Enalapril group) and in 10 patients with cardiac failure taking diuretics alone (Control group). Total 4 h diuresis in the erect position was 728 ml and in the supine position was 824 ml in the patients taking enalapril compared to 655 ml in the erect position and 1166 ml in the supine position in those patients taking diuretics alone. Total 4 h natriuresis in the erect positions was 78 mmol and in the supine position was 85 mmol in patients taking enalapril 10 mg twice daily but in those patients taking diuretics alone total 4 h natriuresis in the erect position was 67 mmol increasing to 120 mmol in the supine position. Measurements of plasma renin activity and plasma angiotensin II concentration confirmed effective converting enzyme inhibition, in the group of patients taking enalapril, but in those patients taking diuretics alone the erect position was associated with an increase in plasma renin activity, and plasma concentrations of angiotensin II and aldosterone. We conclude that the renin angiotensin system is a major factor in mediating the effect of posture on loop diuretic drugs.
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PMID:The influence of posture on the response to loop diuretics in patients with chronic cardiac failure is reduced by angiotensin converting enzyme inhibition. 162 97

The hemodynamic, hormonal, and renal effects of angiotensin II-type 1 receptor antagonism (AT1A) have not been documented previously in heart failure (HF) or compared with angiotensin-converting-enzyme inhibition (ACEI). Accordingly, we investigated the acute (2-h) response to losartan (1 and 10 mg/kg iv) or vehicle (N saline) followed by captopril (12.5 mg) on separate days in an ovine model of HF induced by 7 days of rapid ventricular pacing. Losartan induced a significant rise in plasma renin activity (PRA) and plasma angiotensin II levels (P less than 0.01 and P less than 0.001, respectively), in association with a fall in the plasma aldosterone-to-PRA ratio (P less than 0.001) and plasma atrial natriuretic peptide (P less than 0.05). Mean arterial and left atrial pressure both fell significantly after losartan (P less than 0.001), whereas the rise in cardiac output was not sustained. The response to captopril was similar except for plasma angiotensin II, which declined (P less than 0.001). Glomerular filtration and urine sodium excretion were maintained despite a fall in renal perfusion pressure. In conclusion, the vasodilatation and renal effects of AT1A were similar to ACEI. Thus AT1A may be a useful therapeutic alternative to ACEI in HF.
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PMID:Angiotensin II receptor antagonism in ovine heart failure: acute hemodynamic, hormonal, and renal effects. 163 62


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