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

The two major causes of death in congestive heart failure (CHF) are progressive heart failure (approximately 60% of cases) and sudden death (30%). Sudden death in CHF is caused primarily by malignant ventricular arrhythmias. The underlying mechanism has yet to be established, but myocardial metabolic factors are probably involved. Although there is a clear association between complex ventricular arrhythmias and left ventricular function, it has not been shown convincingly that antiarrhythmic agents can reduce sudden death in CHF. Progressive deterioration of myocardial function is associated with altered myocardial energy production. Notably, the physiological effects of neuroendocrine activation in chronic CHF may be deleterious to myocardial function. The CONSENSUS study was carried out to evaluate the association between neuroendocrine activation and deterioration of myocardial function using ACE inhibitors. A marked reduction in mortality rate occurred in the enalapril-treated group, where the one-year mortality was reduced by 31%. The reduction in mortality was solely among patients with progressive CHF (a reduction of 50%); there was no difference in the incidence of sudden death. Analysis of blood samples drawn at baseline in the placebo group showed a significant positive correlation between mortality and plasma angiotensin II (P less than 0.05), aldosterone (P = 0.003), noradrenaline (P less than 0.001), adrenal levels (P less than 0.001), and atrial natriuretic peptide (P = 0.003). This was not observed in enalapril-treated patients. The significant reduction in mortality in the enalapril group was found consistently among patients with baseline hormone levels above the median value. In CHF, the underlying disease may induce serious arrhythmias and/or progressive failure.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Mechanisms for improved survival in heart failure. 255 Jun 46

Isolated calcium-tolerant rat ventricular cardiomyocytes were used to characterize the effects of atrial natriuretic peptide (ANP), Angiotensin II (AII) and their interaction on the myocardial contraction-/relaxation pattern free of interference from other types of cardiac cells. Binding of 125I-ANP showed a KD of 12 pM and approximately 600 binding sites per cell. At 37 degrees C (rate 140 bpm) ANP decreased the contraction maximum with an EC50 of about 70 pM, maximal decrease was 35%. ANP (10(-7) M) raised cellular cyclic-GMP from 0.76+/-0.12 to 1.32+/-0.13 pmole/10(6) cells (73%, p less than 0.05). Angiotensin II increased contractility by a maximum of 32% at 10(-7) M; the EC50 was 8 x 10(-10) M. AII markedly delayed relaxation (reduction of maximum relaxation velocity from 0.092 to 0.063 mm/s; p less than 0.05). ANP (10(-7) M) increased the effect of AII (10(-8) M) on contractility by 66% without changing relaxation parameters significantly. This unexpected interaction may be relevant in pathological conditions where both AII and ANP are stimulated, such as heart failure or secondary hypertension.
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PMID:Action of atrial natriuretic peptide and angiotensin II on the myocardium: studies in isolated rat ventricular cardiomyocytes. 255 Dec 88

The temporal relationship of changes in atrial natriuretic peptide (ANP) secretion to other pathophysiological changes in heart failure has not been investigated. We studied the hemodynamic, hormonal, and metabolic changes before, during, and after the induction of heart failure in eight sheep using a 14-day period of rapid left ventricular pacing (LVP). Arterial pressure declined 21% on the first day, while cardiac output fell progressively to 48% of base line, and atrial pressures rose to a plateau over the first week. Plasma ANP levels increased 10-fold with a close correlation to left atrial pressure in all sheep. Furthermore, ANP secretion appeared to be sustained throughout the LVP period but did not prevent avid sodium retention. Marked and early activation of the renin-angiotensin system was observed, whereas the major increase in plasma aldosterone commenced 4 days later. On termination of LVP, a prompt natriuresis and diuresis occurred with return of all parameters toward base line. Thus this ovine model is useful for studying pathophysiological changes during the onset and offset of heart failure.
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PMID:Neurohumoral changes during onset and offset of ovine heart failure: role of ANP. 256 90

Vasoactive humoral factors were measured in 27 patients before and during the first week of conventional treatment of acute heart failure. On admission, all patients were given frusemide intravenously, followed by oral digoxin and diuretic therapy. Before drug treatment, plasma renin activity and plasma angiotensin II concentrations were within normal ranges in the group of patients without previous diuretic treatment, but were significantly higher in those 16 patients already on diuretic drugs when admitted to hospital. After diuretic treatment, however, even the former group revealed activation of the renin-angiotensin system. Plasma concentrations of catecholamines were increased initially but normalized within 1 day. A majority of the patients initially had very high plasma concentrations of atrial natriuretic peptide (mean 276.9 +/- 39.0 pg ml-1) which decreased but did not normalize during the study period. High plasma levels of arginine vasopressin (mean 56.8 +/- 14.6 pg ml-1) were found, but tended to be reduced during treatment. Thus, patients with acute heart failure displayed increased plasma concentrations of atrial natriuretic peptide, arginine vasopressin and catecholamines, but these vasoactive hormones decreased in parallel to clinical improvement during diuretic therapy. In contrast, the renin-angiotensin system became clearly activated.
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PMID:Neuroendocrine response in acute heart failure and the influence of treatment. 257 29

Cirrhosis is associated with several circulatory abnormalities. A hyperkinetic circulation characterized by increased cardiac output and decreased arterial pressure and peripheral resistance is typical. Despite this hyperkinetic circulation, some patients with alcoholic cirrhosis have subclinical cardiomyopathy with evidence of abnormal ventricular function unmasked by physiologic or pharmacologic stress. Florid congestive alcoholic cardiomyopathy develops in a small percentage, but the concurrent presence of cirrhosis seems to retard the occurrence of overt heart failure. Even nonalcoholic cirrhosis may be associated with latent cardiomyopathy, although overt heart failure is not observed. Tense ascites is associated with some cardiac compromise, and removing or mobilizing ascitic fluid by paracentesis or peritoneovenous shunting results in short-term increases in cardiac output. Cirrhosis also appears to be associated with a decreased risk of major coronary atherosclerosis and an increased risk of bacterial endocarditis. Small hemodynamically insignificant pericardial effusions may be seen in ascitic patients. The release of atrial natriuretic peptide appears to be unimpaired in cirrhosis, although the kidney may be hyporesponsive to its natriuretic effects.
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PMID:Cardiac abnormalities in liver cirrhosis. 269 Apr 63

To elucidate further the possible role of atrial natriuretic peptide (ANP) and hypothetical natriuretic hormone (NH) in volume and BP regulation in chronic renal failure (CRF) we measured plasma ANP, digitalis-like substances (DLS) and Na+-K+-ATPase activity (using 86Rb influx into RBC) in 9 patients with CRF before and after hemodialysis. Volume expansion between consecutive dialyses led in all patients to the elevation of plasma ANP (83.4 +/- 14.2 pmol/l) reaching in some overhydrated subjects and/or patients with concomitant cardiac insufficiency concentration greater than 150 pmol/l. Reduced 86Rb influx into RBC before hemodialysis (37.7 +/- 4.9% of controls) was accompanied by higher DLS concentrations (201 +/- 32 pmol/l). Ultrafiltration during hemodialysis with ECFV reduction lowered both ANP and DLS concentrations to 28.1 +/- 9.4 pmol/l and to 151 +/- 23 pmol/l, respectively, and abolished partly the inhibition of Na+-K+-ATPase activity (64.9 +/- 7.6% of controls). These changes corresponded to the degree of ECFV alteration. Our results suggest that both natriuretic principles are activated during ECFV expansion in CRF, probably as a corrective mechanism, with a tendency to normalize when ECFV is reduced during hemodialysis.
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PMID:Atrial natriuretic peptide concentration and natriuretic hormone activity in plasma of patients with chronic renal failure. 285 Sep 86

Plasma atrial natriuretic peptide levels are increased in heart failure. In rats with experimental heart failure, the elevation in plasma atrial natriuretic peptide bore a close relationship to the size of the myocardial infarct and the degree of ventricular dysfunction. Sodium retention, assessed by changes in exchangeable body sodium, could not be demonstrated in this model of cardiac dysfunction. Even rats receiving a low-sodium diet had increased plasma atrial natriuretic peptide levels following coronary artery ligation despite a significant decrease in exchangeable body sodium. This establishes that the elevated plasma atrial natriuretic peptide levels found in heart failure are a consequence of ventricular dysfunction and increased intracardiac pressures rather than a reflection of the salt and water status. Alternatively, the elevated plasma atrial natriuretic peptide may limit salt and water retention in this model. In these animals with high circulating atrial natriuretic peptide levels, "down-regulation" of renal atrial natriuretic peptide receptors could be demonstrated. This decrease in renal atrial natriuretic peptide receptor numbers may, in part, explain the blunted response to infused atrial natriuretic peptide in heart failure. However, changes in renal atrial natriuretic peptide receptors alone would appear to be insufficient to lead to salt and water retention without the activation of other sodium-retaining mechanisms that occur with the progression of cardiac failure. Nevertheless, this down-regulation of renal atrial natriuretic peptide may then contribute to the salt and water retention that occurs in congestive biventricular heart failure. The close relationship between increases in atrial natriuretic peptide and ventricular dysfunction rather than sodium balance suggests that atrial natriuretic peptide's primary role in the circulation may be to produce venodilation and increase capillary permeability. This may act rapidly to reduce cardiac preload and prevent pulmonary congestion. Vasodilation and natriuresis may then become supplementary actions to maintain cardiac output and remove the excess fluid.
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PMID:Regulation of cardiac preload by atrial natriuretic peptide in congestive cardiac failure. 285 Dec 66

In chronic cardiac failure, various neurohumoral mechanisms are activated to sustain blood volume, blood pressure, and organ perfusion. Using the coronary artery ligation model of heart failure in the rat, we have measured changes in vasoactive hormone secretion and related these changes to salt and water status during a 1-month period. When compared with controls, rats with infarction had a marked rise in plasma atrial natriuretic peptide (294 +/- 59 vs. 79 +/- 10 pg/ml, p less than 0.001) although there was no increase in total exchangeable body sodium. Plasma renin activity and plasma aldosterone concentrations were the same for both rats with infarction and controls. Similarly, there were no significant differences in plasma arginine vasopressin, plasma osmolality, or plasma sodium concentration in rats with infarction. Ventricular norepinephrine levels were reduced in animals with infarction (p less than 0.01). Plasma atrial natriuretic peptide levels were raised in this model of chronic left ventricular failure. However, there was no salt retention and little stimulation of the renin-angiotensin-aldosterone system or vasopressin. The results suggest that high circulating atrial natriuretic peptide levels may prevent or limit salt and water retention, either directly or indirectly, by inhibiting the renin-angiotensin-aldosterone system.
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PMID:Neurohumoral responses to chronic myocardial infarction in rats. 289 63

To define the relation between atrial pressures and the release of atrial natriuretic peptide, we measured plasma concentrations of the peptide in 26 patients with cardiac disease--11 with normal atrial pressures and 15 with elevated atrial pressures (11 of these 15 had elevated pressures in both atria). Mean peptide levels (+/- SEM) in the peripheral venous blood were increased in the 11 patients with cardiac disease and normal atrial pressures, as compared with 60 healthy controls (48 +/- 14 vs. 17 +/- 2 pmol per liter). In the patients with elevated atrial pressures, peptide concentrations were increased twofold in peripheral venous, right atrial, pulmonary arterial, and systemic arterial plasma, as compared with the concentrations in the patients with normal atrial pressures. A step-up in peptide concentration was seen between the venous and right atrial plasma (P less than 0.002) and between the pulmonary and systemic arterial plasma (P less than 0.01), suggesting release of the peptide from the atria. A linear relation was found between right atrial pressure and right atrial peptide concentration (r = 0.835, P less than 0.001) and between pulmonary wedge pressure and the systemic arterial peptide concentration (r = 0.866, P less than 0.001). Right atrial pressure and the peptide concentration both increased with exercise testing in the nine patients evaluated. We conclude that the release of atrial natriuretic peptide is at least partly regulated by right and left atrial pressures. Distinguishing the relative contributions of the two atria and defining the role of peptide release in the pathogenesis of heart failure will require further investigation.
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PMID:Atrial natriuretic peptide and atrial pressure in patients with congestive heart failure. 294 77

To assess the relation between atrial natriuretic peptide and ventricular dysfunction, we simultaneously measured both atrial and plasma immunoreactive atrial natriuretic peptide concentrations in rats 4 weeks after myocardial infarction induced by left coronary artery ligation. When compared to controls (n = 39), rats with infarction (n = 16) had markedly elevated plasma immunoreactive atrial natriuretic peptide concentrations (1205.8 +/- 180.9 vs. 126.7 +/- 8.9 pg/ml, p less than 0.001) and reduced immunoreactive atrial natriuretic peptide concentrations in right and left atria (31.4 +/- 4.6 vs. 61.2 +/- 3.2 ng/mg, p less than 0.001; 14.9 +/- 2.2 vs. 32.7 +/- 2.4 ng/mg, p less than 0.001, respectively). Right ventricular weight increased in proportion to infarct size, and both were correlated with plasma immunoreactive atrial natriuretic peptide levels (r = 0.825, p less than 0.001 and r = 0.816, p less than 0.001, respectively). Right atrial immunoreactive atrial natriuretic peptide content was significantly higher than left in both controls and rats with infarction. Both right and left atrial immunoreactive atrial natriuretic peptide concentrations were negatively correlated with both right ventricular weight as well as plasma immunoreactive atrial natriuretic peptide concentrations (right atrium: r = -0.816, p less than 0.001, r = -0.708, p less than 0.01; left atrium: r = -0.687, p less than 0.01, r = -0.644, p less than 0.01, respectively). These results suggest that chronic stimulation of atrial natriuretic peptide release from both atria is associated with increased turnover and depleted stores of atrial natriuretic peptide in atria in proportion to the severity of heart failure. It also suggests that plasma atrial natriuretic peptide levels may be used as a reliable index of cardiac decompensation in chronic heart failure.
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PMID:Atrial natriuretic peptide in chronic heart failure in the rat: a correlation with ventricular dysfunction. 294 70


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