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

A retrospective analysis of the informativeness of certain methods of examination for ascertaining the possibility of cardiac failure developing in the subacute period of penetrating, predominantly primary transmural myocardial infarction with no clinical signs of cardiac failure in the first three days after the onset of the disease. In 60 patients circulation time in the "arm--ear" area and in 25 of them the stroke and minute volumes by the dye dilution method were studied. The state of the fluid spaces was investigated in 18 patients and daily natriuresis in 23. In 36 patients the condition of the pulmonary circulation was judged by means of roentgenogram. The high value of the information gained from study of circulation time and natriuresis and X-ray examination in the prognostication of the development of cardiac failure is shown.
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PMID:[Retrospective evaluation of various methods of examination for prognosis of cardiac insufficiency in the subacute period of myocardial infarct]. 33 63

The effect on the left ventricle of changes in the state of the arterial vasculature is best identified by utilizing calculations of pulsatile rather than steady flow phenomena. Impedance is the most satisfactory term to describe this effect. The normal ventricle compensates for changes in impedance largely by changes in preload, but the damaged heart loses this compensatory ability and its stroke volume becomes inversely related to outflow resistance. Patients with heart failure behave in a similar fashion and pharmacologic vasodilation may induce marked improvement in left ventricular pump function. Inappropriate vasoconstriction in heart failure may result from stimulation of the sympathetic or renin-angiotensin system. Early experience with converting enzyme inhibitors suggests that blockade of the formation of angiotensin II may be a useful means of treating some patients with heart failure.
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PMID:Role of vasoconstrictor mechanisms in the control of left ventricular performance of the normal and damaged heart. 38 61

The method of radionuclide cardangiography (RNCA) has become a well-established method amongst non-invasive assessments in coronary heart disease (CHD). By means of RNCA the most important parameters of left ventricular function, viz. ejection fraction (EF) and wall motion (WM), can be determined very exactly. The first bolus pass method (FBP), which allows satisfactory separation between right and left heart, enables the additional determination of EF distribution, stroke volume (SV) and SV distribution. This method requires the technical necessity of a multicrystal gamma camera. Special nuclear medicine characteristics have been worked out for different groups of CHD. EF and WM show typical signs of angina pectoris, caused by exercise correlating with reduced perfusion in the referring section of WM. While these changes may be reversible after nitrate administration, pathological myocardial function caused by acute myocardial infarction (AMI) or manifest heart failure is not reversed by nitroglycerine. Typical findings were seen in the course of AMI: initial decrease in global EF and diffuse (multilocated) asynergies in the left ventricular wall; in the second week possible start of recovery, including regression of dyskinesia to akinesia at the end of hospitalization. Especially in the early phase of AMI it was demonstrated that FBP--as a non-invasive technique--gives high information quality which is unequalled by other comparable methods. Therefore, the described method of FBP should be classified as very useful and effective in clinical cardiology.
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PMID:[Radionuclide cardangiography as non-invasive assessment in coronary heart disease (author's transl)]. 39 49

The effects of induced hypocapnia, hypothermia, and hypertension were surveyed in a primate model of acute stroke during and following a 48-hour period of intensive care. The results were compared to a group of nine control animals previously studied. Hypocapnia (PaCO2=25 torr) was examined in five animals and did not appear to alter the expected mortality, degree of neurological deficit, or frequency of infarction. There was, however, a suggestion that the size of infarction may be reduced. Hypothermia (29 degrees C) in five animals had a detrimental effect in that no animals survived following the intensive care period and all had infarction with massive edema. We speculate that hypothermia caused a sufficient increase in blood viscosity as to compromise collateral flow, thereby accounting for this detrimental effect. Induced hypertension (to 20% above control levels) was abandoned after three animals because of severe systemic effects (cardiac failure and pulmonary edema) resulting in death during the period of intensive care.
Stroke
PMID:Failure of prolonged hypocapnia, hypothermia, or hypertension to favorably alter acute stroke in primates. 40 43

In patients with chronic heart failure exercise allows the simultaneous observation of the cardiovascular pathophysiology and the symptoms of these patients. We administered short-term, oral prazosin to 10 patients with severe chronic heart failure. Prazosin increased cardiac output and stroke volume significantly during exercise (both P less than 0.05) but not at rest (both P greater than 0.10). Prazosin decreased the arteriovenous oxygen difference and left ventricular filling pressure significantly during exercise (both P less than 0.05) but not at rest (both P greater than 0.10). There was no significant correlation between prazosin-induced changes at rest and during exercise in cardiac output (r = 0.12), stroke volume (r = 0.02), arteriovenous oxygen difference (r = 0.33) or left ventricular filling pressure (r = 0.43). Prazosin predominantly affects hemodynamics during exercise because its pharmacologic activity as an alpha-adrenergic blocking agent is most prominent during exercise. The full evaluation of prazosin-induced changes in the hemodynamics of patients of patients with chronic heart failure requires evaluation during exercise.
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PMID:Paradox of improved exercise but not resting hemodynamics with short-term prazosin in chronic heart failure. 42 18

Plasma dobutamine concentrations and hemodynamic and noninvasive cardiac measurements were made during dobutamine infusions in eight patients with congestive cardiomyopathy and low output heart failure. Plasma concentrations correlated well with infusion rates (2.5, 5.0, 7.5 and 10 microgram/kg/min). Cardiac output and stroke volume increased linearly, whereas pulmonary capillary wedge pressure, and total pulmonary and systemic resistances decreased linearly with increasing dobutamine concentrations. No constant relationship existed between plasma dobutamine levels and changes in heart rate or mean arterial pressure. The noninvasive left ventricular function data (echocardiographic and systolic time intervals) correlated linearly with plasma concentrations and suggest that these noninvasive technics be employed in guiding the administration of this new inotropic agent.
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PMID:The relationship between plasma dobutamine concentrations and cardiovascular responses in cardiac failure. 42 67

Studies were made on 21 patients, 8 without any symptoms of left ventricular failure, group 1, and 13 with clinical symptoms of heart failure, group 2. Cardiac output, mean aortic and left ventricular pressures (using catheter tip micromanometer), and ventricular volume (obtained from left ventricular cineangiograms) were measured before and during nitroprusside infusion. The heart rate did not change in either of the groups. Only in group 2 did cardiac index and stroke volume increase significantly. Mean aortic pressure and total systemic vascular resistance decreased significantly in both the groups. Left ventricular end-diastolic pressure decreased significantly in both the groups, but this decrease was greater in group 2 (9 mmHg compared with 3 mmHg for group 1). The decrease in the left ventricular end-diastolic volume was similar in both the groups. The decrease in left ventricular end-systolic pressure was greater in group 1, but the decrease in the left ventricular end-systolic volume was greater in group 2. These facts are explained by the differences in the active and passive left ventricular pressure-volume relations in the two groups.
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PMID:Study of left ventricular pressure-volume relations during nitroprusside infusion in human subjects without coronary artery disease. 42 81

In contrast to intravenously-administered crystallene glucagon, which acts for 20 minutes only, the depot form, zinc protamine glucagon, shows a prolonged haemodynamic action. Fourteen patients with pre-existing heart failure received a single dose of 20 mg Zn protamine glucagon intramuscularly. The stroke volume and cardiac output were increased, whereas the mean and end-diastolic pulmonary pressure were decreased, indicating a positive inotropic action of the administered drug. Heart rate and mean arterial pressure remained almost unchanged. The haemodynamic changes started 60 minutes after intramuscular administration of the drug, reached a maximum effect at 3 hours and started to decrease after the fourth hour. Zn protamine glucagon can, therefore, be considered a beneficial drug in the treatment of digitalis-resistant heart failure on the basis of its long duration of action and easy route of administration.
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PMID:[Haemodynamic effects of depot zinc protamine glucagon in heart failure (author's transl)]. 43 80

In order to avoid thrombi generation within artificial ventricles the Ellipsoid heart is built with a one-piece membran in enddiastolic position. This allows to have an optimal washout of all inside surfaces during the cardiac cycles, in enddiastolic position the cross sectional veiw of the membran is circle-shaped. 82% of the filling volume can be used for the maximal stroke volume, which is 120 ml. The maximal cardiac output is 16 l/min. The Ellipsoid heart is evaluated as design for total heart replacement and assisted circulation. As total artificial heart the survival times were in calves experiments up to 40 days, in assisted circulation in parakorporeal position up to 83 days. The cardiac assistance with the Ellipsoid heart (E-LVAD) is performed due to implanted canula in the left ventricle via the left atrium and a connection to the ascending aorta. This technique was applied in 14 clinical cases with cardiac failure after open surgery. The E-LVAD could support the failing heart; it could be removed in 4 patients. The aim to avoid thrombiformation within artificial ventricles could be achieved with the Ellipsoid heart in calve experiments as well as clinically--the membrane was constantly clean and free of any thrombidepositions.
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PMID:[The ellipsoid heart. Construction and animal experimental findings of a new kind of artificial heart]. 45 3

Beneficial effects of nitroprusside infusion in heart failure are purportedly a result of decreased afterload through "impedance" reduction. To study the effect of nitroprusside on vascular factors that determine the total load opposing left ventricular ejection, the total aortic input impedance spectrum was examined in 12 patients with heart failure (cardiac index <2.0 liters/min per m(2) and left ventricular end diastolic pressure >20 mm Hg). This input impedance spectrum expresses both mean flow (resistance) and pulsatile flow (compliance and wave reflections) components of vascular load. Aortic root blood flow velocity and pressure were recorded continuously with a catheter-tip electromagnetic velocity probe in addition to left ventricular pressure. Small doses of nitroprusside (9-19 mug/min) altered the total aortic input impedance spectrum as significant (P < 0.05) reductions in both mean and pulsatile components were observed within 60-90 s. With these acute changes in vascular load, left ventricular end diastolic pressure declined (44%) and stroke volume increased (20%, both P < 0.05). Larger nitroprusside doses (20-38 mug/min) caused additional alteration in the aortic input impedance spectrum with further reduction in left ventricular end diastolic pressure and increase in stroke volume but no additional changes in the impedance spectrum or stroke volume occurred with 39-77 mug/min. Improved ventricular function persisted when aortic pressure was restored to control values with simultaneous phenylephrine infusion in three patients. These data indicate that nitroprusside acutely alters both the mean and pulsatile components of vascular load to effect improvement in ventricular function in patients with heart failure. The evidence presented suggests that it may be possible to reduce vascular load and improve ventricular function independent of aortic pressure reduction.
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PMID:Aortic input impedance during nitroprusside infusion. A reconsideration of afterload reduction and beneficial action. 45 74


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