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

Coupling of myocardial beta-, beta 1-, beta 2- and alpha-adrenoceptors (AR) to myocardial contraction was investigated in patients with various degrees of heart failure. With the use of delta Vcfc, a load independent parameter of myocardial contraction, AR mediated contraction was evaluated. beta-AR mediated contraction, delta Vcfc by infusion of a beta-AR agonist, isoproterenol, declined with the advancement of heart failure from 0.41 Circ/sec (NYHA I) to 0.31 (NYHA II), 0.22 (NYHA III) and 0.12 (NYHA IV). Dobutamine, a beta 1-AR full agonist, mediated delta Vcfc was 92-97% of that of isoproterenol. On the other hand, terbutaline sulfate, a full agonist to beta 2-AR, increased delta Vcfc partially in comparison with isoproterenol; 51% in NYHA I, 52% in NYHA II, 36% in NYHA III and 17% in NYHA IV. An alpha 1-AR agonist, methoxamine had little effect on myocardial contractility beta-AR and alpha-AR densities were analyzed by saturation binding isotherms of myocardial membrane fraction with 125I-Iodocyanopindolol (ICYP) and 3H-Bunazosin, respectively. beta-1 and beta 2-ARs were separated by competition binding of 125ICYP with a highly selective beta 1 AR antagonist, CGP20712A. There was a progressive down regulation of beta, beta 1- and beta 2-ARs with the advancement of heart failure. A new index was used to examine coupling of ARs to myocardial contraction; Coupling Index. The index was slightly decreased in NYHA II in beta- and beta 1-ARs. In beta 2-AR, the coupling index declined as heart failure advanced from NYHA I to NYHA IV.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Increased uncoupling of beta-, beta 1- and beta 2-adrenoceptor to myocardial contraction in failing human myocardium. 132

Beta-adrenergic stimulants (Dobutamine and Dopamine) and recently introduced phosphodiesterase inhibitors (PDI) such as Amrinone, Milrinone, Enoximone and Piroximone are the principal inotropic agents for the treatment of acute cardiac failure. Most of the hemodynamic effects of these drugs are comparable, but peripheral vasodilatation is more marked with PDI. A potential advantage of the latter group is the lack of development tolerance, which occurs within 48 to 72 hours after beta-stimulants. On simultaneous administration, additive effects can be observed. Short term clinical results with PDI are good, especially in patients with postoperative cardiocirculatory failure, including cardiogenic shock. In contrast, long-term oral treatment with Amrinone, Milrinone and Enoximone in recent studies was disappointing. Efficacy was not superior to Digoxin, and unwanted side effects were frequent. Intermittent instead of continuous administration of positive inotropic agents should be evaluated in patients with severe congestive heart failure not responding to vasodilators and diuretics.
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PMID:[New positive inotropic drugs in acute and chronic heart failure]. 135 9

Acute rejection often leads to severe myocardial failure and death. Surprisingly, no systematic study on the efficacy of beta-adrenergic pharmacologic agents have been reported to the present. Because of all the pathophysiologic alterations documented during rejection, we expected an inappropriate response to inotropic drugs, so we have questioned the value of dobutamine during those circumstances. Twelve dogs underwent orthotopic transplantation and were prepared with implantable devices for serial hemodynamic studies to be performed on the resting unanesthetized subject. Of this number, six dogs were studied while they were in immediate postoperative heart failure (3 hours after operation), and the same study was performed when myocardial failure secondary to rejection occurred (5 to 7 days). After basal state measurement, 5 and 10 micrograms.kg-1.min-1 of dobutamine were infused continuously, and the hemodynamic response during the two phases was compared. The baseline cardiac index in the immediate postoperative period was 1.4 +/- 0.4 L.min-1.m2 and 1.8 +/- 1.0 L.min-1.m2 during rejection, showing a similar degree of heart failure. Dobutamine (5 micrograms.kg-1.min-1) increased cardiac index by 97% 3 hours after transplantation and by 35% during rejection (p < 0.05). With 10 micrograms.kg-1.min-1 of dobutamine, the difference between increments was not significant (99% versus 79%). Raising the infusion rate of the drug to 15 and 20 micrograms.kg-1.min-1 during rejection increased cardiac index by 97% and 118%, respectively. Interestingly, no detrimental tachycardia occurred with this increased dosage. Heart failure secondary to acute rejection can therefore be improved by dobutamine.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Efficacy of dobutamine in the failing transplanted heart. 145 37

Twenty patients (two female, 18 male, mean age 57 +/- 11 years) with severe heart failure NYHA IV (7 coronary artery disease, 13 congestive cardiomyopathy) were treated with 8.8 +/- 1.7 micrograms.kg-1 x min-1 of dobutamine. Pulmonary gas exchange was analysed by withdrawal of blood samples from a central venous catheter and a radial artery cannula. Dobutamine increased SvO2 from 58.7 +/- 11.2% to 72.2 +/- 6.3% (P = 0.0001) and decreased avDO2 from 7.7 +/- 2.45 Vol% to 4.97 +/- 1.34 Vol% (P = 0.0001). PaO2 and PaCO2 were not changed. Qs/Qt increased slightly from 9.1 +/- 8.3% to 11.3 +/- 6.4% (P = 0.035). Cardiac index increased by 51% (P = 0.0001), pulmonary capillary wedge pressure decreased by 28% (P = 0.0001). In patients with severe heart failure, dobutamine improved haemodynamics without detrimental effects on arterial oxygen concentration.
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PMID:Effect of dobutamine on pulmonary gas exchange in patients with severe heart failure. 146 44

The contractile function of the left ventricle has been defined within the framework of the pressure-volume relationship. We employed a conductance catheter, together with a high-fidelity micromanometer, to obtain accurate pressure and volume data continuously on a beat-to-beat basis in conscious dogs. Reproducibility of conductance volumetry was proven by repeated in situ measurements of left ventricular volume on separate days in the same dog. Heart failure, produced by rapid ventricular pacing, was characterized by impaired systolic shortening, depressed contractility indices and incomplete left ventricular relaxation. The magnitude of the cardiotonic effects of dobutamine was significantly attenuated after development of heart failure. Dobutamine improved left ventricular early relaxation but did not affect chamber distensibility. In heart failure, the load sensitivity of relaxation was enhanced and the force-frequency response attenuated. This may elucidate the mechanisms of early diastolic dysfunction and the deleterious effect of an increase in heart rate in the failing heart. Thus, the conductance catheter provided a reliable and simple method of obtaining left ventricular volume continuously in conscious dogs.
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PMID:Continuous measurement of the pressure-volume relationship in experimental heart failure produced by rapid ventricular pacing in conscious dogs. 147 9

Sixty-three patients (aged from 4 to 75 years) who had suffered severe head injury or cerebrovascular disease were placed on barbiturate regimens in which intravenous administration was given in amounts of 1-4 mg/kg/hr. Dobutamine and dopamine were also administered to prevent cardiac failure and renal failure. Immediate and delayed complications caused by barbiturate therapy were investigated and analyzed. Immediate complications included tachycardia which was seen in 16 cases (25%), and hypotension in 14 cases (22%), respectively. Higher incidence of those complications was noted among the patients who underwent surgery. Delayed complications included hypokalemia (41 cases, 65%), liver dysfunction hypernatremia (24 cases, 38%), infection (21 cases, 33%), cardiac failure (8 cases, 13%) and renal failure (1 case, 2%), respectively. Therefore, in patients treated under barbiturate regimens great care should be taken in order to avoid above mentioned complications.
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PMID:[Problems in general management during barbiturate therapy]. 148 90

Dobutamine is the standard inotrope used as cardiac support for hyperdynamic hypermetabolic patients following acute surgical stress. Amrinone has been utilized in medical patients with heart failure, but its use in hyperdynamic patients to our knowledge has never been reported. We now report the results of a trial of amrinone versus dobutamine in this setting. Over a 3-month period, we compared 28 trials of dobutamine and 27 trials of amrinone in 47 patients. Attempts were made to achieve non-flow-dependent oxygen consumption. Values are expressed as pre/post inotrope. Student's two-tailed t test was used for evaluation. [table: see text] Patients treated initially with dobutamine were slightly younger (mean, 46 vs. 57 years). They required slightly higher doses of dobutamine (mean, 12.9 vs. 12.2 micrograms/kg/min) and a slightly longer treatment period (mean, 11.3 vs. 9.8 hours) to achieve the desired effect. Of the 47 trials with dobutamine, six (13%) failed to achieve non-flow-dependent oxygen consumption. All then responded somewhat to amrinone. The failure rate for amrinone was 10%. No patient developed hypotension when treated with either drug. Amrinone is an effective inotrope useful in the cardiovascular support of hyperdynamic patients following surgical stress. Hypotension is not a problem with adequate intravascular volume loading. It should become part of the standard drug regimen in the surgical ICU.
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PMID:Amrinone as an inotrope in managing hypermetabolic surgical stress. 154 27

The hemodynamic effects of dobutamine, milrinone, and a combination of both drugs were compared intra-individually in 14 patients with severe heart failure (NYHA III: n = 9; NYHA IV: n = 5). Dobutamine (maximum dose: 9 micrograms/kg/min) and milrinone (0.5 micrograms/kg/min) each induced a comparable increase in stroke volume index (21 to 29 resp. 21 to 30 ml/m2; mean values; p less than 0.001) and reduction in pulmonary capillary wedge pressure (29 to 22 resp. 28 to 21 mm Hg; p less than 0.001), as well as in systemic (1846 to 1218 resp. 1858 to 1276 dyn s/cm5; p less than 0.001) and pulmonary vascular (301 to 195 resp. 293 to 216 dyn s/cm5; p less than 0.001) resistances. The heart rate rose significantly after dobutamine (92 to 107 min-1; p less than 0.05), but did not change after milrinone (94 to 95 min-1; ns). Neither drug had a significant effect on systemic arterial pressures. The combination of milrinone and dobutamine induced a further significant rise in stroke volume index (37 ml/m2; p less than 0.01) when compared to either drug alone. The combination also caused an additional fall in pulmonary capillary wedge pressure (14 mm Hg; p less than 0.01), as well as in systemic (799 dyn s/cm5; p less than 0.001) and pulmonary (133 dyn s/cm5; p less than 0.001) vascular resistances. When compared to dobutamine alone, the combined therapy did not significantly change the heart rate and systemic arterial pressures. The combined administration of a beta-adrenergic agonist and a phosphodiesterase inhibitor induces beneficial hemodynamic effects.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:[Additive effects of milrinone and dobutamine in severe heart failure]. 162 7

The clinical usefulness of cardiac imaging modalities that rely upon the detection of perfusion defects and wall motion disturbances requires conditions that provoke a heterogeneity of coronary flow and a myocardial oxygen imbalance, respectively. Traditionally, this has been achieved by exercise stress testing. Many patients cannot perform dynamic exercise sufficiently for various reasons. Pharmacologic stress has been proven to be an attractive alternative for physical exercise. Currently, several stressing agents are used in conjunction with thallium-201 scintigraphy, 2-D echocardiography and, recently, MRI. The most employed agents include vasodilators, such as dipyridamole and adenosine, and catecholamines, such as dobutamine (Table VI). The predominant rationale of thallium-201 perfusion scintigraphy is based on the creation of a flow maldistribution between territories supplied by normal arteries and those supplied by stenotic arteries that does not necessarily require ischemia. Dipyridamole and adenosine, as rather selective coronary vasodilators, are well suited to provoke such a condition and may be classified as the ideal markers of myocardial perfusion. 2-D echocardiography and MRI have the potential to provide noninvasively derived information of cardiac dynamics and regional myocardial function. To assess the functional significance of coronary artery disease, detection of wall motion abnormalities and alterations in ejection fraction require the presence of myocardial ischemia. Dobutamine, as a widely applied inotropic agent in the management of severely depressed left ventricular contractile function, seems to be an appropriate pharmacologic stressor when heart failure is absent. By increasing contractility, heart rate, and systolic arterial pressure, it is capable of inducing an imbalance between myocardial oxygen demand and supply, leading to ischemia in patients with coronary artery disease.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:New developments in pharmacologic stress imaging. 163 90

Dobutamine is frequently used for acute therapy in heart failure. In the present study, the hemodynamic effects of long-term intermittent dobutamine therapy were investigated in conscious rats with heart failure. Rats with healed myocardial infarctions received two i.p. injections of dobutamine per day for 2 weeks. Hemodynamic measurements were performed 90-180 min after the last injection. Two weeks of intermittent dobutamine significantly restored all hemodynamic changes induced by infarction. The maximal cardiac output during volume loading was depressed due to infarction and dose-dependently restored by 2 weeks of intermittent dobutamine. An increased stroke volume accounted for this improvement since the heart rate was not altered. In order to investigate changes in adrenergic responsiveness, the effects of acute dobutamine in nontreated and 2 weeks of dobutamine-treated infarcted rats were compared to those in control rats. Whereas chronotropic responses to acute dobutamine were comparable for all experimental groups, the inotropic response was reduced in nontreated infarcted rats but dose-dependently restored after 2 weeks of intermittent dobutamine therapy. From the data, we conclude that 2 weeks of intermittent dobutamine therapy in conscious rats with healed myocardial infarcts improved cardiac performance and restored the inotropic response to acute dobutamine administration. Data indicate that dobutamine has a long-term effect on cardiac function, which differs from the acute inotropic effect.
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PMID:Two weeks of intermittent dobutamine therapy restores cardiac performance and inotropic responsiveness in conscious rats with heart failure. 171 20


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