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

The isolated perfused working rat heart preparation has been used to study the effects of respiratory acidosis on myocardial metabolism and contractilly. Hearts were perfused with 5 mM glucose and 10(-2) U/ml of insulin in order to enhance metabolsim of glucose relative to that of fatty acids. After perfusion with Krebs bicarbonate medium at pH 6.6, hearts rapidly ceased performing external work and peak left ventricular pressure fell by 75% after 5 minutes. Oxygen consumption, rate of ATP generation and overall glycolytic flux also declined rapidly. After about 2 minutes of perfusion, the fall of glycolytic flux showed a partial reversal, which was largely accounted for by increased lactate production, so that glucose oxidation decreased further. The reversal of glycoltic flux could be accounted for by partial release of H+ inhibition of phospho-fructokinase by increased tissue levels of adenosine 5'-diphosphate (ADP), adenosine monophosphate (AMP) and P1 and decreased levels of adenosine triphosphate (ATP) and creatine phosphate. The increased proportion of glucose uptake converted to lactate together with an increase of the tissue lactate/pyruvate ratio could be accounted for by inhibition of the malate-aspartate cycle combined with tissue hypoxia. Lactate accumulated in the tissue as a result of a decreased permeability of the plasma membrane to lactate. Decreased oxygen delivery to the myocardium was caused by secondary constriction of the coronary vessels. In further experiments, the coronary flow was regulated by an external pump which delivered fluid at a controlled rate into the aortic cannula above the coronary arteries, and the degree of tissue hypoxia was monitored by measuring changes of pyridine nucleotide reduction state by surface fluorescence techniques. The effects of acidosis uncomplicated by possible hypoxia were compared directly with those produced by ischemic hypoxia. The effects of acidosis under these conditions were similar to those described above, and to those produced by ischemia. From these and other data it is concluded that the effects of ischemia are caused by a lowering of the intracellular pH, which decreases the rate of energy production relative to the rate of energy demand. However, it is suggested that the primary cause of the decreased peak systolic pressure with either acidosis or ischemia is not a result of a defect of energy metabolism, but is due to alteration of the calcium cycle of the heart. Possible causes of irreversible heart failure after prolonged ischemia are discussed.
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PMID:Contribution of tissue acidosis to ischemic injury in the perfused rat heart. 0 93

A systematic search for cases of lactic acidosis among diabetics on biguanides revealed ten during an eight-month period, while in the preceding ten years not a single case had been definitely diagnosed. This represents a prevelance of 1 in 2000 patients admitted to hospital. All ten were over 60 years old and had previously been treated for heart failure. Most of them had suffered from renal insufficiency for some time. There was no case of biguanide overdosage. Criteria for the diagnosis of lactic acidosis are lactic concentration in blood averaging 18.4 mmol/l and a low pH, averaging 6.9. Serum-biguanide concentration (measured by radioimmuno-assay) was markedly increased. Most of the patients were in circulatory shock on admission or soon after and all of them had a history of gastro-intestinal complaints. Despite intensive treatment with insulin and glucose and careful correction of the acidosis with bicarbonate four of the ten patients died.
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PMID:[Lactic acidosis in diabetics on biguanides (author's transl)]. 1 84

Changes in myocardial water content, left ventricular diastolic stiffness, cardiac performance, coronary blood flow, myocardial contractile force, rate of change of myocardial force, and peak acceleration of the aortic volume flow were examined in twenty-five dogs during glucose-induced hyperosmolality before and after pancreatectomy, the latter with and without insulin treatment. Glucose-induced hyperosmolality accounted for myocardial dehydration, increased diastolic stiffness and consequent decrease of left ventricular performance only in the absence of insulin, while coronary blood flow, myocardial contractile force, rate of change of myocardial force and peak acceleration of the aortic volume flow increased independently from the presence or absence of insulin during the glucose-induced hyperosmolality. These findings suggest that the frequent development of heart failure in hyperosmolar diabetic coma could partly be explained by myocardial dehydration and by the consequent decrease in left ventricular compliance and performance.
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PMID:Effect of hyperglycaemia-induced hyperosmolality on heart function in the dog. 11 46

The relationship between energy metabolism and the extent of irreversible ischemic damage was examined in an isolated perfused working rat heart. The amount of cardiac work recovered after reperfusion of hearts exposed to severe global ischemia was dependent upon both the duration of ischemia and the type of substrate provided (either 5 mM glucose or 5 mM glucose + acetate). There appear to be two distinct phases in the ability to recover mechanical function in the reperfused ischemic heart. The second phase corresponds to the onset of severe irreversible tissue damage. Irreversible mitochondrial damage was not found to correspond with the onset of heart failure since the ATP/ADP ratio remained constant in the reperfused myocardium. Furthermore, there does not appear to be a direct correlation between the total ATP content and the extent of irreversible damage, either during ischemia or following reperfusion. However, the total adenine nucleotide content during ischemia showed dramatic changes which correspond temporally with the initiation of the second phase of damage. The observation that the adenine nucleotide pool becomes further depleted during reperfusion suggests that alterations in the salvage pathway for adenine nucleotide synthesis have occurred. Loss of adenine nucleotides appears to be an excellent marker for irreversible heart failure. Acetate provides some protection the the ischemic myocardium. The mechanism by which acetate mediates this protective effect is discussed.
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PMID:Relationship between adenine nucleotide metabolism and irreversible ischemic tissue damage in isolated perfused rat heart. 44 6

1. Hydrochlorothiazide (HCT, 50-75 mg) was administered orally to seven patients with cardiac failure. 2. Plasma levels and urinary concentration of HCT were determined by GLC. 3. The gastrointestinal uptake of the diuretic in three patients was reduced to approximately half that seen in healthy controls. 4. Plasma halflife of HCT was correlated with endogenous creatinine clearance. 5. Pharmacokinetics of HCT are considerably changed in cardiac failure.
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PMID:Pharmacokinetics of hydrochlorothiazide in patients with congestive heart failure. 46 80

The relationships between left ventricular function and myocardial O2 availability and metabolism were studied in cats with hemorrhagic shock (AP=30 mm. Hg) with the use of a right heart bypass preparation. Aortic flow and heart rate were held constant. Oxygen-carrying capacity was reduced by diluting donor blood with an equal volume of 5 per cent glucose in saline. Oxygen availability was estimated as the product of arterial O2 content and coronary blood flow. All shock animals showed a progressive metabolic acidemia with time, and a fall in coronary flow concomitantly. Four control animals (AP=75 mm. Hg) as well as two shock animals with high arterial oxygen content and hematocrit showed no significant changes in myocardial O2 metabolism or performance over a period of 90 minutes. Nine shock animals with reduced hematocrit demonstrated a progressive reduction in ventricular function, myocardial O2 metabolism, and O2 availability. As O2 availability fell below 10 ml. per minute per 100 Gm. of heart weight, cardiac failure uniformly appeared and was accompanied by a reduction in O2 extraction and consumption. The correlation between left ventricular dP/dt max and O2 availability was highly significant (r = 0.75, p less than 0.01) in shock animals but not in controls. Thus a close relationship between myocardial O2 metabolism and function during the course of hemorrhagic shock has been demonstrated. Reduced myocardial O2 availability is directly linked with the appearance of cardiac failure.
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PMID:Myocardial oxygen availability and cardiac failure in hemorrhagic shock. 94 31

Past studies reported by this laboratory have documented myocardial dysfunction and progressively developing hypoglycemia in canine endotoxin shock. The purpose of the present study was to determine the effects of glucose concentrations and insulin infusions on myocardial performance following endotoxin administration. Experiments were carried out on isolated, working canine left ventricular heart preparations exchanging blood with intact dogs. Myocardial function was evaluated following endotoxin and correlated with concentrations of glucose and effects of insulin infusion. Cardiac dysfunction occurred within 2-4 hr postendotoxin and the degree of malfunction was not related to arterial blood glucose concentrations. Maintaining blood glucose at control, preshock, levels by infusion of 50% glucose did not prevent myocardial dysfunction as evidenced by elevations of left ventricular end diastolic pressure, and depressed power. Infusions of insulin reversed cardiac failure and maintained normal performance in spite of wide ranges in glucose concentration (5-120 mg%). Findings suggest that myocardial dysfunction is not precipitated or enhanced by the hypoglycemia of endotoxin shock. The beneficial actions of infused insulin on cardiac performance appear to be elicited on the basis of mechanisms other than myocardial glucose transport.
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PMID:Effects of glucose or insulin on myocardial performance in endotoxin shock. 96 82

Two hundred and twelve patients with acute myocardial infarction were treated for 14 days with daily doses of potassium (3 gm orally), glucose (280 gm orally) and regular insulin (16 units subcutaneously), all given in 4 fractional doses. The incidences of arrhythmias, heart failure and systolic blood pressure below 70 mm Hg, as well as the mortality rate, were compared with those for another group of 600 myocardial infarction patients who were not given this treatment. Though there was some reduction in the incidence of cardiac arrhythmias, it was not statistically significant. However, there was a strikingly significant decrease in the incidences of heart failure and blood pressure below 70 mm, as well as in the early mortality rate. Our findings should encourage the continued use of potassium, glucose and insulin therapy in acute myocardial infarction.
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PMID:Potassium, glucose and insulin administration in acute myocardial infarction: a five-year study. 99 44

Dobutamine (dobutamin hydrochloride, Lilly) is a new inotropic catecholamine; it is presented in lyophilized ampoules for I.V. use, each containing 250 mg of dobutamine to be reconstituted with 5 per cent glucose or sterile water for injection. In the first part of this study, animal pharmacology is reported as described in medical literature: inotropic activity with minimal chronotropic effects, direct action, no vasconstriction, minimal arrhythmogenic activity and minimal diversion of blood flow to skeletal muscles are the main experimental features. The authors report afterwards their own experience with dobutamine in 8 patients (cranial traumas) without cardiac failure, and in 9 patients presenting with a cardio-circulatory failure in a toxi-infectious condition. In all patients tested, hemodynamics parameters (heart rate, mean A.P., central venous pressure) and cardiac output measurement (dye dilution method) were performed. Cardiac index and systolic index, total systemic resistances, left ventricular performance were also calculated. Dobutamine dosage ranged from 2.5 to 10 mcg/kg/mn except in patients with low output syndrom (2.5 and 5 mcg/kg/mn). Dobutamine offers new possibilities by its constant and indisputable inotropic activity contrasting with its minimal chronotropic effect.
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PMID:[A comparative study of the cardiovascular effect of dobutamine. Preliminary results obtained in a surgical resuscitation unit]. 101 59

Patients in the coronary care unit with acute pulmonary edema, heart failure, and other organic heart disease were studied. Blood and urine samples were taken on admission prior to any treatment and later at prescribed intervals. All the patients with APE were found to have elevated plasma osmolalities and hyperglycemia on admission which decreased with treatment. This was in contrast to the other two groups excluding those factors such as ethyl alcohol and diabetes which can raise plasma osmolality or blood glucose. A discussion of this mild hyperosmolal state in APE follows including possible causes as well as cellular effects of hyperosmolality on humans.
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PMID:Acute pulmonary edema and hyperosmolality: a clinical study. 106 77


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