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

Digitalis and diuretics constitute conventional therapy of congestive heart failure, but systemic vasodilators offer an innovative approach in acute and chronic heart failure of decreasing increased left ventricular systolic wall tension (ventricular afterload) by reducing aortic impedance and/or by reducing cardiac venous return. Thus, vasodilators increase cardiac output (CO) by diminishing peripheral vascular resistance (PVR) and/or decrease increased left ventricular end-diastolic pressure (LVEDP) (ventricular preload) by diminishing venous tone. Concomitantly, there is reduction of myocardial oxygen demand, thereby reliably reducing angina pectoris in coronary disease, and potentially limiting infarct size and ischemia provided systemic arterial pressure remains normal. The vasodilators produce disparate modifications of cardiac function depending upon their differing alterations of preload versus impedance: nitrates principally cause venodilation (decrease LVEDP); nitroprusside, phentolamine and prazosin produce balanced arterial and venous dilation (decrease LVEDP and increase CO) provided left ventricular filling pressure is maintained at the upper limit of normal; whereas hydralazine predominantly effects arteriolar dilation (increases CO). With depressed CO plus highly increased LVEDP and increased PVR, nitrates also induce some increase of CO by reducing PVR. Combined nitroprusside and dopamine synergistically enhance CO and decrease LVEDP. Mechanical counterpulsation aids nitroprusside in acute myocardial infarction. The 30-minute venodilator action of sublingual nitroglycerin is extended for 4 to 6 hours by cutaneous nitroglycerin ointment, by sublingual and oral isosorbide dintrate, and by oral pentaerythritol tetranitrate and sustained-release nitroglycerin capsules. Ambulatory oral vasodilator therapy is provided by long-acting nitrates (relieve pulmonary congestion); hydralazine (improves fatigue); prazosin alone, combined nitrate-hydralazine combined prazosin-hydralazine (improve both dyspnea and fatigue).
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PMID:Afterload reduction and cardiac performance. Physiologic basis of systemic vasodilators as a new approach in treatment of congestive heart failure. 9 30

The effects of moderately rapid oral digitalization and sublingual nitroglycerine were studied in 13 patients with coronary heart disease without signs of manifest heart failure but definite rise in pulmonary artery pressure on ergometric exercise. Digitalis had no effect on exercise-induced rise in pulmonary pressure. In the individual case there may be a clear-cut deterioration in exercise response. This possible unfavourable digitalis effect cannot be predicted in a given case from the clinical state and thus one must critically assess digitalis treatment in coronary heart disease without manifest heart failure. On the other hand, the favourable effect of nitroglycerine in lowering pulmonary arterial pressure at rest and preventing an abnormal pressure rise on exercise underlines its value in the treatment of both compensated and uncompensated coronary heart disease.
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PMID:[Comparison of the effects of digitalis and nitroglycerine in coronary heart disease with cardiac failure on exercise (author's transl)]. 41 40

Although an inotropic effect of digitalis on skeletal muscle has been demonstrated in animals, it has not been shown in man. Digitalis, in previous studies, has failed to improve voluntary exercise performance. In this investigation the strength of nerve-stimulated involuntary thumb adduction was measured before, during and after infusion of ouabain into the brachial artery. With this experimental design, the many uncontrolled factors that govern ordinary exercise tolerance were avoided. Large doses of ouabain (0.5 mg) produced significant augmentation of peak strength of thumb adduction whereas smaller doses (75 mug) more likely to reach the thumb during systemic digitalization produced only suggestive increases in peak contraction strength. In patients previously digitalized for heart failure, the large doses of ouabain did not significantly change contractility. The findings suggest that skeletal muscle is less sensitive than cardiac muscle to ouabain, and that systemic digitalization has a minor effect on skeletal muscle. When the differences between skeletal and cardiac muscle in excitation-contraction coupling are considered, the reduced effect of ouabain on skeletal muscle contraction is compatible with cell membrane locus of action in both tissues.
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PMID:Effect of digitalis on skeletal muscle in man. 77 59

In treating heart failure, the physician must remain cognizant of pathophysiology as he prescribes and monitors therapy. In addition to seeking underlying and precipitating causes of the patient's heart failure, he must treat the congestive state by enhancing myocardial contractility, controlling excessive fluid retention, and reducing afterload. Figure 7 summarizes the theoretical shifts on a patient's left ventricular function curves that might occur with therapy. Left ventricular function might move from point A to point B with diuretic therapy, but overdiuresis could aggravate symptoms of low cardiac output, including postural hypotension. Digitalis would effect a shift from A to C. Isosorbide dinitrate would produce a shift from A to D in a patient not on digitalis and from C to D in a patient already receiving digitalis. Isosorbide dinitrate, in conjunction with more usual therapeutic measures, has proved clinically beneficial in the treatment of heart failure.
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PMID:Treatment of congestive heart failure. 82 68

So-called nonocclusive or spastic mesenteric infarction is a well-known complication of severe circulatory failure with low cardiac output and hypotension. In recent years, acute mesenteric insufficiency has been described in connection with certain drugs. Clinical and experimental evidence suggests a relationship between digitalis therapy, especially overdigitalization, and nonocclusive mesenteric infarction. Two cases are presented in support of this hypothesis. Both patients had digitalis intoxication and died from nonocclusive mesenteric infarction proven by surgery, autopsy and, in one case, arteriography. No cause other than digitalis intoxication (shock, severe cardiac failure or other drugs) could be found. Despite the frequent occurrence of digitalis intoxication, nonocclusive mesenteric infarction is a rare event. Interruption of digitalis therapy does not alter the usually fatal outcome. Experimental data with glucagon and phenoxybenzamine suggest that a therapeutic trial with these drugs might be worth while. Digitalis should be used with caution in shocked patients, since in these the splanchnic circulation is usually critical.
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PMID:[Mesenteric infarct during digitalis poisoning]. 116 97

Between 1969 and 1991, 11 patients were followed up for permanent junctional reciprocating tachycardia. The average age at diagnosis was 2 years and 4 months (1 day to 14 years). The tachycardia was diagnosed at routine examination in 5 cases and following an episode of cardiac failure in the other 6. Digitalis was prescribed in all patients with 4 good results, 5 average and 2 poor results. One patient, who remained in mild cardiac failure with digitalis therapy, died suddenly at the age of 9 years. In more recent cases, amiodarone was used from the onset or secondarily with good results in all patients. In 2 patients, in whom amiodarone was withdrawn after 3 months and 3 years' treatment, there was a recurrence of the tachycardia. No side effects of amiodarone therapy were observed in this series. Three patients were prescribed flecainide with 1 good and 2 average results. Propranolol, used in 2 cases, was associated with 1 average and 1 poor result. Disopyramide and Verapamil were ineffective. These results suggest that amiodarone is the drug to choose in permanent junctional reciprocating tachycardia but it must be given long term. The persistence of cardiac failure, poor control of the tachycardia or secondary effects of drug therapy should lead to consideration of non-medical management of the tachycardia.
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PMID:[Permanent junctional reciprocating tachycardia in children and adolescents. Efficacy of medical treatment]. 153 Mar 93

A pathophysiologic hallmark of heart failure is neurohormonal excitation, a prominent feature of which is activation of the sympathetic nervous system. Studies from our laboratories demonstrate that clinical heart failure is characterized by marked increases in efferent sympathetic neural outflow to muscle; the magnitude of this sympatho-excitation parallels the degree of cardiac dysfunction. Impairments of cardiopulmonary and arterial baroreflex sensory mechanisms appear to be responsible to a significant degree for this sympatho-excitation, consistent with findings in animal models of heart failure. Digitalis glycosides exert modest inotropic actions when administered to patients with heart failure. Digitalis also has potent autonomic effects that can potentiate impaired arterial and cardiopulmonary baroreflex mechanisms in experimental models of cardiac dysfunction. Acute digitalis administration to patients with moderate-to-severe heart failure produces profound and sustained sympatho-inhibition, which precedes any observed hemodynamic action of the agent. Further, acute digitalization of such patients rapidly normalizes impaired baroreflex-mediated mechanisms. Data now suggest that the mechanism of action of digitalis in humans is an acute potentiation of baroreceptor-mediated afferent regulation of sympathetic neural mechanisms. Prospective, randomized and controlled studies now are required to test the hypothesis that the acute effects of digitalis on autonomic mechanisms also are observed during chronic administration. In theory, the chronic sympatho-inhibitory action of digitalis, combined with its chronic potentiation of impaired baroreflex mechanisms, may offer beneficial effects independent of its inotropic actions in patients with heart failure.
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PMID:Digitalis and neurohormonal abnormalities in heart failure and implications for therapy. 162 90

Despite major advances in the prevention and treatment of cardiovascular diseases, the incidence and prevalence of congestive heart failure (CHF) have been increasing in recent years. As the average age of the population increases, the prevalence of CHF is expected to continue to increase. The number of deaths in which CHF was considered the underlying or contributing cause increased from 51,000 in 1955 to 274,000 by 1988 in the United States. Even accounting for population growth and an increase in the number of elderly, this represents a 2-fold increase. Additionally, CHF was responsible for about 643,000 hospitalizations in 1988. Digitalis is one of the drugs most commonly prescribed for CHF and has been used for greater than 200 years. In 1990, digoxin was one of the most commonly prescribed drugs in the United States, accounting for greater than 21 million prescriptions. There has been little decline in the drug's use over the last 5 years, indicating that newer treatments for CHF have not replaced the widespread use of digitalis. Despite these findings, considerable controversy surrounds the appropriateness of its role and value in treating CHF patients who are in sinus rhythm. A number of recent, uncontrolled studies have arrived at apparently contradictory conclusions concerning the effects of digitalis on mortality in postmyocardial infarction and heart failure patients. A large, double-blind, randomized, controlled clinical trial to evaluate the effects of digitalis on mortality, morbidity and quality of life is being sponsored by the National Heart, Lung, and Blood Institute in conjunction with the Department of Veterans Affairs Cooperative Studies Program.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Need for a large randomized trial to evaluate the effects of digitalis on morbidity and mortality in congestive heart failure. 162 93

Few studies have been conducted that focus on survival as the end point of medical therapy of CHF. No vigorous studies have been conducted in dogs. It is generally accepted that diuretic therapy is an essential component of the therapy of CHF in cardiomyopathic dogs. Significant symptomatic improvement is afforded by diuretics, and acute death may be prevented. In this context diuretics can be said to improve survival. However, diuretics do not alter the natural progression of cardiomyopathy and in this context do not favorably influence long-term survival. Digitalis glycosides have been shown in humans to improve various parameters of CHF in a subset of patients with either atrial fibrillation or third heart sounds. In dogs, these gallop heart rhythms due to third heart sounds are usually associated with myocardial failure due to dilated cardiomyopathy. In spite of symptomatic improvement, no study has demonstrated an unequivocal favorable effect of digoxin on survival of patients with dilated cardiomyopathy. Likewise, there is no convincing evidence of an adverse effect on survival. Newer, powerful inotropes, such as milrinone, often demonstrate impressive short-term improvements in left ventricular function, clinical signs, and exercise tolerance in patients with CHF. However, their long-term benefits are much less impressive, they are arrhythmogenic, and they have not been shown to prolong survival. In fact, long-term milrinone therapy in humans has had an unfavorable influence on mortality. Vasodilators offer the potential advantage of increasing left ventricular performance without an associated increase in myocardial oxygen demand and cardiac rhythm disturbances. The only vigorous survival study that unequivocally demonstrated improved survival of patients with advanced CHF due to myocardial failure, including dilated cardiomyopathy, was the Consensus Trial. Survival of patients receiving enalapril was significantly better than those receiving placebo. In fact, the trial was stopped prematurely by the ethical review committee when it became obvious that the results favored the enalapril group. Although the use of beta-adrenergic blocking drugs in cardiomyopathic patients with CHF is controversial and associated with a risk of short-term deterioration of left ventricular function, their use in human medicine is gaining acceptance. Although hemodynamic and clinical evidence of improvement has been demonstrated along with withdrawal-associated deterioration, the only study purporting a beneficial effect on survival used retrospective controls.(ABSTRACT TRUNCATED AT 400 WORDS)
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PMID:Effect of medical therapy on survival of patients with dilated cardiomyopathy. 168 46

The role of digitalis therapy in patients with sinus rhythm and mild to moderate heart failure has been a subject of controversy. This review critically examines the relevant literature and specifically evaluates trials in this patient population. The pharmacokinetics and the pharmacodynamics of the most commonly prescribed agents are briefly discussed. The available evidence supports the use of this agent in patients with sinus rhythm and clinical signs of systolic dysfunction. Digitalis is not recommended as a routine when the primary cause of heart failure is diastolic dysfunction. The use of digitalis therapy in combination with diuretics and vasodilator therapy deserves further attention.
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PMID:[Digitalis therapy in patients with heart failure and sinus rhythm]. 194 43


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