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

In acute and chronic left heart failure peripheral resistance is elevated due to increased sympathetic tone. This should compensate the decrease in stroke volume. In the diseased left ventricle however the augmentation of afterload leads to further reduction of stroke volume and to increase of heart size and myocardial oxygen consumption. This vitious cycle may be interrupted by vasodilators. Drugs like nitroglycerin, mainly acting on the venous system, reduce preload and thereby relieve symptoms of pulmonary congestion (backward failure). Phentholamin on the other hand primarily reduces afterload by an action on the resistance vessels and thereby increases cardiac output (forward failure). Nitroprusside has effects on both, the capacity and resistance vessels. So nigroglycerin is the remedy of choice in acute pulmonary edema. Nitroprusside in leftf heart failure in acute myocardial infarction and Phentolamin in acute left ventricular failure due to critical rise in blood pressure. For long term treatment of chronic left heart failure (coronary heart disease, cardiomyopathy, rheumatic heart disease) hydralazin or prazosin may be used as well as long acting nitrates.
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PMID:[Progress in the therapy of acute and chronic cardiac insufficiency by means of systemic vasodilators. Studies with prazosin and nitroglycerin]. 12 80

To assess the circulatory effects of afterload reduction and inotropism individually and in combination as rational therapy for refractory heart failure, nitroprusside and dopamine were administered to 13 patients with severe cardiac decompensation. Dopamine at average doses of 3 and 7 microgram/kg per min produced increases in cardiac output and reductions in peripheral resistance. At doses of 15 microgram/kg per min, dopamine increased heart rate, peripheral arterial pressure and side effects. Nitroprusside alone decreased left-sided filling pressures and increased cardiac output. When the agents were administered together, the increases in cardiac output were significantly greater than with either agent alone and there was physiologic improvement in overall circulatory function. The relations among changes in afterload (systemic impedence), preload (filling pressures) and cardiac index help to explain the salutary effects of combined therapy in patients with refractory heart failure.
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PMID:Combined nitroprusside-dopamine therapy in severe chronic congestive heart failure. Dose-related hemodynamic advantages over single drug infusions. 68 39

Sodium nitroprusside is a potent, effective, and readily reversible direct vasodilating agent. It is broken down by hemoglobin into cyanide, which is in part detoxified by liver and kidney to thiocyanate. Some cyanide, especially in nitroprusside- "resistant" individuals who need large amounts of the drug, appears to remain free to cause cyanide poisoning. Patients requiring inordinate amounts probably should not continue to receive the drug, although maximum dosage limits for long-term therapy are not established. Blood thiocyanate levels do not indicate the extent to which free cyanide is limiting oxygen utilization in essential tissue, nor do blood cyanide levels. Metabolic acidosis, elevated lactate levels, elevated lactate/pyruvate ratios, and elevated mixed venous blood oxygen content are at present the best indications of the presence of cyanide poisoning during nitroprusside administration. Nitroprusside appears useful for induction of hypotension during surgery, and for treatment of hypertensive emergencies from all causes, although continuance for more than a few days is probably unwise. The reductions of cardiac afterload and ventricular filling pressure by nitroprusside appear useful in treatment of severe myocardial failure or infarction, but studies of myocardial cyanide toxicity are needed before complete acceptance of this therapy is warranted. Initial dose rates between 0.5 and 1.5 mug/kg/min are recommended only as starting points for very careful titration. Total projected intra-operative dosage should be calculated as quickly as possible and should not exceed 3-3.5 mg/kg. It is hoped that future studies will reveal the maximum dose of nitroprusside that can safely be metabolized in a 24-hour period, and may indicate that cofactors of rhodanase such as thiosulfate, or cobalamins such as hydroxocobalamin, can be administered with nitroprusside to prevent cyanide poisoning.
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PMID:Sodium nitroprusside: pharmacology, toxicology and therapeutics. 96 81

1. We investigated the haemodynamic effects of intravenously administered hydrallazine, diazoxide and nitroprusside and orally administered minoxidil to determine whether vasodilators (such as nitroprusside) which do not increase cardiac output might be better treatment for hypertensive complications associated with, or caused by, myocardial failure than those that do. 2. Hydrallazine and diazoxide caused increases in heart rate, cardiac output, cardiopulmonary blood volume, the ratio of cardiac output to cardiopulmonary volume, and pulmonary artery pressure. Nitroprusside, although decreasing pressure and vascular resistance, caused no significant change in the other functions except for reducing pulmonary artery pressure. Minoxidil, when given orally, had the potential for causing pulmonary hypertension. This seemed explained by increased flow (hyperdynamic type) in some but by congestive cardiac failure in others; the latter condition was probably intensified by the marked fluid retention that the drug can cause. 3. On the basis of these results a classification of vasodilators was constructed which depends on the presence or absence of a venodilating effect. Vasodilators which produce no (or little) venodilatation, increase heart rate, cardiac output, cardiopulmonary blood volume and pulmonary artery pressure. In this class are diazoxide, hydrallazine and minoxidil. Those that cause venodilatation do not stimulate the heart nor do they cause pulmonary hypertension. Nitroprusside and nitroglycerine are drugs of this type. 4. These results suggest that drugs producing both venodilatation and arteriolar dilatation may be more specific therapy for hypertensive complications associated with cardiac failure than those that cause only arteriolar dilatation.
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PMID:Vasodilating drugs: contrasting haemodynamic effects. 107 83

The effects of unloading a depressed heart were assessed in terms of optimal coupling between the ventricle and arterial system. To assess the effects of preload on ventricular load coupling, preload was reduced with a lower body negative pressure of -20 mm Hg. Nitroprusside was used to evaluate the effects of afterload on the coupling under the condition that preload reduction was comparable to that with lower body negative pressure. In 13 patients with heart failure (ejection fraction 32 +/- 3%, mean +/- SE), direct arterial pressure was simultaneously recorded with the left ventricular echocardiogram as the pressure was elevated by phenylephrine. Left ventricular contractile properties were defined by the slope (Ees) of the end-systolic pressure-volume relation. The effective arterial elastance (Ea) was expressed by the slope of the end-systolic pressure-stroke volume relation. Left ventricular external work, end-systolic potential energy and work efficiency, defined as external work per pressure volume area (external work + potential energy), were determined. Baseline ventricular load coupling in these patients was characterized by an increase in the ratio of arterial elastance to ventricular elastance (Ea/Ees) (1.96 +/- 0.31). This ratio decreased significantly, to 1.45 +/- 0.22, with nitroprusside, and increased to 2.37 +/- 0.34 with lower body negative pressure. Therefore, end-systolic potential energy was decreased by nitroprusside but was unaltered by lower body negative pressure while external work was comparably decreased by both manipulations, indicating that work efficiency was significantly augmented with nitroprusside but declined with lower body negative pressure.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Ventricular load optimization by unloading therapy in patients with heart failure. 198 27

Dopamine1 receptors mediate hemodynamic effects that may be beneficial in patients with congestive heart failure. We infused the selective dopamine1 receptor agonist, fenoldopam mesylate (SKF 82526 J), to evaluate hemodynamic and neurohumoral changes during continuous intravenous infusion in patients with congestive heart failure and compared them with the effects of nitroprusside, a traditional vasodilator that works by a distinctly different mechanism. In 15 patients with a mean radionuclide ejection fraction of 17%, the agents were infused in a random-ordered, double-blinded, crossover, active drug-controlled protocol after optimal dosing was determined during a titration period. Hemodynamic changes were induced in minutes with both drugs during a mean (+/- standard deviation) infusion dose of 1.45 +/- 1.66 micrograms/kg/min for fenoldopam and 2.99 +/- 1.59 micrograms/kg/min for nitroprusside. At 1 hour, mean blood pressure decreased and cardiac index rose with both drugs, and the effect lasted throughout the 6-hour infusion period. Nitroprusside, but not fenoldopam, reduced right heart filling pressures (including mean pulmonary capillary wedge, mean right atrial, and mean pulmonary artery pressures) during the infusion period. Both drugs caused significant reduction in systemic vascular and pulmonary arteriolar resistances. No significant change occurred in plasma norepinephrine levels. Fenoldopam ameliorates some of the adverse hemodynamic changes that occur during heart failure but does not reduce right heart filling pressures as does nitroprusside. Because of fenoldopam's unique characteristics, it may benefit certain patients with heart failure.
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PMID:Intravenous fenoldopam in heart failure: comparing the hemodynamic effects of dopamine1 receptor agonism with nitroprusside. 289 27

To assess whether the phosphodiesterase inhibitor enoximone has a specific, direct effect on left ventricular diastolic function distinct from its inotropic and vasodilator actions, we compared the effects of enoximone and the pure vasodilator nitroprusside in 11 patients with severe heart failure. Mean (+/- SEM) left ventricular ejection fraction was 0.20 +/- 0.03. Simultaneous left ventricular pressure and radionuclide angiographic volume were obtained at baseline, during infusion of nitroprusside, and after intravenous administration of enoximone. Left ventricular end-diastolic pressure (LVEDP) and volume (LVEDV) decreased with both agents (p less than .01 vs control); LVEDP was lower for nitroprusside than for enoximone (p less than .01) despite a similar LVEDV. Nitroprusside decreased the time constant of exponential left ventricular pressure decay, TL (measured by the logarithmic method), from 84 +/- 10 to 65 +/- 8 msec (p less than .01) but had no significant effect on TD (measured by the derivative method), maximum negative dP/dt, or the peak rate of early diastolic filling. Enoximone shortened TL from 86 +/- 12 to 61 +/- 9 msec (p less than .01) and increased maximum negative dP/dt from 897 +/- 101 to 1135 +/- 134 mm Hg/sec (p less than .01) but did not affect TD or the peak filling rate. The left ventricular diastolic pressure-volume relation was shifted downward in only three of 11 patients on nitroprusside and three of 11 patients on enoximone, and these shifts were attenuated by adjusting for simultaneous changes in right atrial pressure.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Diastolic function in patients with severe heart failure: comparison of the effects of enoximone and nitroprusside. 295 73

Arterial wave reflection may adversely influence both left ventricular afterload and ejection performance. Therefore, using multisensor catheter manometers, we derived wave reflection indexes from ascending aortic pressure and velocity recordings in 17 subjects with clinical heart failure secondary to idiopathic dilated cardiomyopathy and 11 control subjects free of detectable cardiovascular disease. Patients were studied at rest as well as during submaximal supine bicycle exercise. Eight of the subjects with cardiomyopathy were also studied during infusion of nitroprusside at rest and on exercise. Reflection indexes decreased on exercise in normal subjects but did not consistently do so in the subjects with heart failure. In both groups the reflected wave on exercise returned earlier during the ejection period. Infusion of nitroprusside at rest in subjects with heart failure had dramatic, and significant, effects on the magnitude and timing of arterial wave reflections. The effect of nitroprusside on reflection magnitude persisted on exercise, although the timing of the reflected wave was disadvantageous. The systemic arterial response to exercise in heart failure is characterized by a smaller change in wave reflection indexes in spite of a comparable decrease in systemic vascular resistance. Nitroprusside diminishes the potentially adverse impact of wave reflections by decreasing the magnitude of the reflected wave and altering its timing. Additional dose titration studies are necessary to fully assess the benefits of pharmacologic vasodilation during exercise.
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PMID:Arterial wave reflection in heart failure. 382 33

The hemodynamic effects of oral captopril and intravenous nitroprusside were compared in 15 patients with severe chronic congestive heart failure. At doses of both drugs titrated so as to produce similar decreases in systemic vascular resistance in each patient, nitroprusside produced substantially greater increases in cardiac index (+0.67 versus +0.31 liters/min/m2, p less than 0.01) but smaller decreases in mean arterial pressure (-18.4 versus -11.0 mm Hg, p less than 0.01) than did captopril. This finding was due to a significant decrease in heart rate with captopril (-7 beats/min, p less than 0.01) which was not seen with nitroprusside, since changes in stroke volume index with both drugs were similar. Nitroprusside produced a decrease in pulmonary arteriolar resistance quantitatively similar to the decrease in systemic vascular resistance, but the decrease in pulmonary arteriolar resistance with captopril was not significant. Despite similar decreases in systemic resistance, captopril produced a greater decrease in left ventricular filling pressure (-10.2 versus -6.9 mm Hg, p less than 0.01) but a smaller decrease in mean right atrial pressure (-3.1 versus -5.3 mm Hg, p less than 0.01) than did nitroprusside. Thus, captopril has actions independent of its systemic vasodilator effects which account for the quantitative differences observed in its hemodynamic responses compared with those of nitroprusside in patients with severe chronic heart failure. These differences support experimental evidence that angiotensin, in addition to its direct systemic arterial vasoconstrictor actions, exerts positive chronotropic effects and alters ventricular compliance but has minimal direct effects on the limb venous circulation and on the pulmonary vasculature.
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PMID:Quantitative differences in the hemodynamic effects of captopril and nitroprusside in severe chronic heart failure. 633 76

Considering the recent rediscovery of the use of alpha-blocking agents in the treatment of hypertension and heart failure, we have studied the haemodynamic effects of 10-methyl-1,6-dimethyl-ergoline-8 beta-methanol-(5-bromonicotinate (nicergoline, Sermion), a new alpha-blocking ergot derivative, on the closed-chest anesthetized dog. For comparative reasons, the effects of nitroglycerin and nitroprusside were studied on the same model. The doses were adjusted to give an identical decrease in blood pressure after 30 min infusion (nearly 30%). Nicergoline did not change the heart rate, decreased total and femoral arterial resistance, did not change the cardiac output or the femoral flow, as opposed to nitroglycerin which decreased the cardiac output and systolic volume, causing a reflex tachycardia and femoral constriction, confirming its predominantly venous effect. Nitroprusside did not cause tachycardia, and the femoral resistances were increased, though less so than with nitroglycerin. Both nitroglycerin and nitroprusside apparently had no direct effect on myocardial performance, whilst nicergoline seemed to increase the myocardial compliance (by a decrease of the sympathetic tone). This drug merits further attention in that it is readily soluble and can easily be administered i.v., for treatment of acute heart failure, for example.
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PMID:Some haemodynamic effects of nicergoline, a new alpha-blocking agent, in the closed-chest anaesthetized dog as compared with nitroprusside and nitroglycerin. 679 41


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