Withdrawal of digoxin from patients with chronic heart failure treated with angiotensin-converting-enzyme inhibitors. RADIANCE Study

Management of patients receiving interferon beta-1b for multiple sclerosis: report of a consensus conference

Results of a double-blind, placebo-controlled study in ambulatory patients with relapsing-remitting MS showed that interferon beta-1b reduced the rate of exacerbations by one-third compared with placebo and limited new disease activity in the brain as evidenced by MRI. Interferon beta-1b, administered subcutaneously at a dosage of 0.25 mg (8 million IU) every other day is indicated for the treatment of ambulatory patients with relapsing-remitting MS. Interferon beta-1b may help a wider range of patients, but it should be prescribed only for patients with a diagnosis of clinically definite or laboratory-supported definite MS. The decision to treat a patient with interferon beta-1b should be individualized; that is, based on each patient's clinical presentation and course of MS. The most common adverse effects include (1) injection-site reactions and (2) flu-like symptoms, which are generally manageable and usually abate after the first few months of treatment. Spasticity may increase. Patients with severe depression or suicidal ideation should be monitored carefully, and symptomatic treatment should be pursued. Interferon beta-1b is contraindicated in pregnant and nursing women. Interferon beta-1b is effective in reducing the progression of total disease burden as seen on MRI in patients with MS. Its use is relatively straightforward and generally does not require alteration in the symptomatic treatment of MS. Patient education and support remain the mainstays of maintaining compliance through the early phases of therapy.

Selection and treatment of candidates for heart transplantation. A statement for health professionals from the Committee on Heart Failure and Cardiac Transplantation of the Council on Clinical Cardiology, American Heart Association

Improved outcome of heart failure in response to medical therapy, coupled with a critical shortage of donor organs, makes it imperative to restrict heart transplantation to patients who are most disabled by heart failure and who are likely to derive the maximum benefit from transplantation. Hemodynamic and functional indexes of prognosis are helpful in identifying these patients. Stratification of ambulatory heart failure patients by objective criteria, such as peak exercise oxygen consumption, has improved ability to select appropriate adult patients for heart transplantation. Such patients will have a poor prognosis despite optimal medical therapy. When determining the impact of individual comorbid conditions on a patient's candidacy for heart transplantation, the detrimental effects of each condition on posttransplantation outcome should be weighed. Evaluation of patients with severe heart failure should be done by a multidisciplinary team that is expert in management of heart failure, performance of cardiac surgery in patients with low left ventricular ejection fraction, and transplantation. Potential heart transplant candidates should be reevaluated on a regular basis to assess continued need for transplantation. Long-term management of heart failure should include continuity of care by an experienced physician, optimal dosing in conventional therapy, and periodic reevaluation of left ventricular function and exercise capacity. The outcome of high-risk conventional cardiovascular surgery should be weighed against that of transplantation in patients with ischemic and valvular heart disease. Establishment of regional specialized heart failure centers may improve access to optimal medical therapy and new promising medical and surgical treatments for these patients as well as stimulate investigative efforts to accelerate progress in this critical area.

Hospitalized congestive heart failure patients with preserved versus abnormal left ventricular systolic function: clinical characteristics and drug therapy

PURPOSE

To compare clinical characteristics of and pharmacologic therapy for hospitalized patients with congestive heart failure (CHF) and left ventricular systolic dysfunction or normal left ventricular systolic function.

PATIENTS AND METHODS

Medical records were reviewed for all patients discharged with a principal diagnosis of CHF from a university hospital and a community hospital between September 1, 1991 and August 31, 1992. Pertinent medical history items and prescribed drug therapies at discharge were recorded for each patient's first calendar year admission. Patients were categorized as having either normal left ventricular systolic function or systolic dysfunction based on the results of echocardiography and radionuclide angiography or contrast ventriculogram.

RESULTS

Of 298 patients with CHF, 92 (31%) had normal left ventricular systolic function. Patients with normal systolic function were older, were more often women, were less likely to have a history of coronary artery disease, and were more likely to have a history of hypothyroidism than patients with systolic dysfunction. However, the prevalence of clinical characteristics overlapped considerably between the two groups. Among patients with systolic dysfunction, 79% were discharged on a therapeutic regimen of digoxin, 65% on an angiotensin-converting enzyme inhibitor, and 26% on either a beta-blocker or a calcium channel blocker. Among patients with normal systolic function, 50% were discharged on a regimen of a beta-blocker or a calcium channel blocker and 38% were discharged on digoxin. Twenty-six percent of patients with normal systolic function and without a history of atrial fibrillation were discharged on a digoxin regimen.

CONCLUSION

Hospitalized CHF patients with normal left ventricular systolic function and those with diminished left ventricular systolic function share many clinical features. Since recommended drug therapy and prognosis differ, our data underscore the importance of diagnostic testing to assess left ventricular systolic function. Drug therapy for CHF patients provides a major challenge for quality-of-care improvement.

Improving survival for patients with advanced heart failure: a study of 737 consecutive patients

OBJECTIVES

This study sought to determine whether survival and risk of sudden death have improved for patients with advanced heart failure referred for consideration for heart transplantation as advances in medical therapy were systematically implemented over an 8-year period.

BACKGROUND

Recent survival trials in patients with mild to moderate heart failure and patients after a myocardial infarction have shown that angiotensin-converting enzyme inhibitors are beneficial, type I antiarrhythmic drugs can be detrimental, and amiodarone may be beneficial in some groups. The impact of advances in therapy may be enhanced or blunted when applied to severe heart failure.

METHODS

One-year mortality and sudden death were determined in relation to time, baseline variables and therapeutics for 737 consecutive patients referred for heart transplantation and discharged home on medical therapy from 1986 to 1988, 1989 to 1990 and 1991 to 1993. Medical care was directed by a single team of physicians with policies established by consensus. From 1986 to 1990, the hydralazine/isosorbide dinitrate combination or angiotensin-converting enzyme inhibitors were the initial vasodilators, and class I antiarrhythmic drugs were allowed. After 1990, captopril was the initial vasodilator, given to 86% of patients compared with 46% of patients before 1989. After mid-1989, class I agents were routinely withdrawn, and amiodarone was used for frequent ventricular ectopic beats or atrial fibrillation (53% of patients after 1990 vs. 10% before 1989).

RESULTS

The total 1-year mortality rate decreased from 33% before 1989 to 16% after 1990 (p = 0.0001), and sudden death decreased from 20% to 8% (p = 0.0006). Adjusted for clinical and hemodynamic variables in multivariate proportional hazards models, total mortality and sudden death were lower after 1990.

CONCLUSIONS

The large reduction in mortality, particularly in sudden death, from advanced heart failure since 1990 may reflect an enhanced impact of therapeutic advances shown in large randomized trials when they are incorporated into a comprehensive approach in this population. This improved survival supports the growing practice of maintaining potential heart transplant candidates on optimal medical therapy until clinical decompensation mandates transplantation.

New drugs in the treatment of heart failure

1. Current therapy of heart failure relies on diuretics, positive inotropic compounds and vasodilators. The short-term haemodynamic benefits, especially of the cAMP generators, may be compromised by long-term limitations leading to an increased mortality. In contrast, some vasodilators, especially angiotensin converting enzyme inhibitors, improve survival even in severe heart failure. 2. Modulation of Na(+)- or K(+)-channels and calcium sensitization are positive inotropic mechanisms whose promise in treatment of heart failure needs to be fully explored. 3. The introduction of vasodilator therapy has been a significant advance. Newer compounds act to inhibit the endogenous vasoconstrictors angiotensin II and endothelin, or to potentiate the endogenous vasodilators atrial natriuretic factor and nitric oxide. The full potential of these compounds is yet to be realised.

Effects of increasing maintenance dose of digoxin on left ventricular function and neurohormones in patients with chronic heart failure treated with diuretics and angiotensin-converting enzyme inhibitors

BACKGROUND

Despite almost three centuries of use, the appropriate dosage of digitalis in patients with chronic heart failure and normal sinus rhythm has not been well studied.

METHODS AND RESULTS

We studied 22 patients with heart failure who were receiving constant daily doses of digoxin, diuretics, and angiotensin-converting enzyme (ACE) inhibitors. In 18 patients, the oral daily dose of digoxin was increased from a mean of 0.20 +/- 0.07 to 0.39 +/- 0.11 mg/day corresponding to an increase in the serum digoxin concentration from 0.67 +/- 0.22 to 1.22 +/- 0.35 ng/mL. Radionuclide and echocardiographic left ventricular ejection fraction; maximal treadmill time; heart failure score; serum concentrations of norepinephrine, aldosterone, atrial natriuretic factor, and antidiuretic hormone; and plasma renin activity were obtained before and after the increase in digoxin dose. Subsequently, 9 patients were randomized to receive digoxin and 9 to receive placebo and radionuclide ejection fraction measured after 12 weeks. With the higher dose of digoxin compared with the lower dose, there was a significant increase in radionuclide ejection fraction from 23.7 +/- 9.6% to 27.1 +/- 11.8% (P = .007). No significant changes were noted in heart failure score; exercise tolerance; serum concentrations of norepinephrine, atrial natriuretic factor, and antidiuretic hormone; and plasma renin activity. There was, however, an increase in serum aldosterone concentration. Twelve weeks after the patients were randomized to receive digoxin or placebo, there was a significant decrease in ejection fraction (from 29.4 +/- 10.4% to 23.7 +/- 8.9%) in the placebo group but not in patients who continued to receive digoxin (P = .002).

CONCLUSIONS

The increase in maintenance digoxin dose, while maintaining serum concentrations within therapeutic range, resulted in a significant increase in left ventricular ejection fraction that was not associated with significant changes in heart failure score, exercise tolerance, and neurohumoral profile.

Contemporary management of patients with heart failure

Treatment of patients with heart failure has become extremely challenging. A complicated interplay of myocardial, hemodynamic, and humoral factors marking this condition requires a delicate balancing of medication use, procedural intervention, and lifestyle changes. Judicious prescription of therapies in stepwise fashion as the syndrome severity worsens (Fig. 2) is critical to success.

Economic outcomes of withdrawal of digoxin therapy in adult patients with stable congestive heart failure

OBJECTIVES

This study sought to analyze the health and economic outcomes of withdrawal of digoxin therapy among U.S. adult patients with stable congestive heart failure.

BACKGROUND

New information regarding the outcomes of digoxin withdrawal has been provided by the Prospective Randomized Study of Ventricular Failure and Efficacy of Digoxin (PROVED) and Randomized Assessment of Digoxin and Inhibitors of Angiotensin-Converting Enzyme (RADIANCE) trials. We interpreted and extrapolated the results of these trials to describe implications on a national level.

METHODS

We used a decision-analytic model to estimate the outcomes of two alternative strategies to 1) continue and 2) withdraw digoxin in patients with congestive heart failure with normal sinus rhythm, New York Heart Association functional class II or III and left ventricular ejection fraction < or = 35%. Epidemiologic assumptions were derived from published reports and expert opinion. Assumptions regarding the effectiveness of digoxin therapy were derived from the RADIANCE and PROVED digoxin withdrawal trials. Hospital and Medicare data were used for economic assumptions. Calculated outcomes included treatment failures, cases of digoxin toxicity and health care costs.

RESULTS

The continuation of digoxin therapy in these patients with congestive heart failure nationally would avoid an estimated 185,000 clinic visits, 27,000 emergency visits and 137,000 hospital admissions for congestive heart failure. After accounting for an estimated 12,500 cases of digoxin toxicity, the net annual savings would be $406 million, with a 90% range of uncertainty of $106 to $822 million. One-way sensitivity analysis indicated that digoxin therapy is cost-saving when the assumed annual incidence of digoxin toxicity is < or = 33%.

CONCLUSIONS

The continuation of digoxin therapy in patients with stable congestive heart failure should be strongly considered, because this strategy is likely to lead to both lower costs and greater health benefits on the basis of available information.

Long-term denopamine therapy for hemodialysis patients with chronic heart failure

Denopamine was orally administered for more than 12 months to patients with chronic heart failure on maintenance hemodialysis. The plasma level in subjects treated with denopamine at 30 mg/day tended to be higher than that in subjects on 15 mg/day. There was no gradual increase in plasma level as the duration of therapy prolonged. Left ventricular end-diastolic and end-systolic diameters as well as ejection fraction on echocardiography showed a tendency to be improved by denopamine. Similarly, the cardiothoracic ratio was improved temporarily. No adverse effects were detected by electrocardiography and laboratory tests. These observations suggest that denopamine is safe and effective for hemodialysis patients with chronic heart failure.

Angiotensin-converting enzyme inhibitors in the clinical setting of chronic congestive heart failure

The addition of an angiotensin-converting enzyme (ACE) inhibitor to digitalis and diuretics in chronic congestive heart failure (CHF) prolongs survival and improves the clinical condition of patients. These actions depend on the inhibition of ACE and are, therefore, common to all ACE inhibitors. Thus, the inclusion of an ACE inhibitor in the therapeutic regimen of chronic CHF is mandatory, whenever feasible. The use of ACE inhibitors in chronic CHF should avoid symptomatic hypotension and inordinate decreases in renal function. To this end, ACE inhibitor therapy should progress by gradually increasing doses, and sodium intake and dosages of diuretics and ACE inhibitors should be adjusted in the light of changing circumstances. ACE inhibitors with short elimination half-lives should be preferred in chronic CHF, since they allow quicker dose adjustment than their longer-acting congeners, and given that compliance with once and twice daily dosing would be similar.

Coronary artery disease, valvular heart disease, bradycardia, and heart failure

Images

Progression of mild untreated heart failure during six months follow-up and clinical and neurohumoral effects of ibopamine and digoxin as monotherapy. DIMT Study Group. Dutch Ibopamine Multicenter Trial

There is increasing evidence that clinical deterioration in manifest chronic heart failure is related to both hemodynamic and neurohumoral factors. Only few data are available, however, on the progression of disease in its early stages, when treatment has not yet been initiated. The aim of this study was therefore to examine the changes in clinical and neurohumoral variables that occur over 6 months in patients with clinically stable and untreated heart failure, and to evaluate the influence of drugs that may affect these variables. Accordingly, we studied 64 patients with heart failure who were in New York Heart Association functional class II (88%) and III (12%). They were randomized to double-blind treatment with the oral dopamine agonist ibopamine (100 mg 3 times daily; n = 22), digoxin (0.25 mg once daily; n = 22) or placebo (n = 20). Their age (mean +/- SD) was 60 +/- 8 years, and left ventricular ejection fraction (mean +/- SD) was 0.33 +/- 0.08. Of the 64 patients, 56 (88%) completed the 6-month study period (p = NS between groups). Exercise time decreased in patients treated with placebo after 6 months (median -62 seconds; p < 0.05 vs baseline), but it increased with ibopamine (+48 seconds), and digoxin (+17 seconds; both p < 0.05 vs placebo). Plasma norepinephrine increased in the placebo group after 6 months (median + 31 pg/ml, p < 0.05 vs baseline), but decreased in patients receiving active drug treatment (ibopamine: -24 pg/ml, digoxin: -98 pg/ml, both p < 0.05 vs placebo). Plasma renin and aldosterone levels were unchanged after 6 months in the placebo group, but digoxin therapy slightly reduced plasma renin concentration (-5 microU/ml; p < 0.05 vs placebo).(ABSTRACT TRUNCATED AT 250 WORDS)

Heart failure: lessons learned over the past 25 years

Over the past 25 years, a great deal has been learned about the pathophysiology and management of heart failure--a major health problem whose prevalence and incidence have not declined, unlike other cardiovascular disorders. Several of these lessons are reviewed herein. However, despite these advances, important issues remain to challenge both the practicing physician and the research scientist.

Long-term therapy of patients with heart failure. Drug therapy: from trial results to clinical practice

Heart failure (HF) represents a major problem in Western countries due to its high prevalence, frequent need for hospitalization and extremely severe prognosis. There have been remarkable advances in long-term drug therapy. During the last decade, the use of vasodilatators, in particular of angiotensin-converting enzyme (ACE)-inhibitors, has been added to the traditional therapy based on diuretics and digitalis. There have been several controlled clinical trials demonstrating the long-term benefits of these drugs for survival. ACE-inhibitors have reduced the risk of mortality in HF, not only by their systemic vasodilatator action but also by their positive effects on ventricular remodelling. In fact, their use has led to a reduction in the incidence of sudden death, and progression of pump dysfunction. A reduction in the incidence of coronary events was also observed. ACE-inhibitors, in combination with diuretics and digitalis, have been rightfully introduced into long-term therapy of HF. At present, other pharmacological options, like flosequinan, some beta-blockers, and some calcium antagonists such as felodipine and amlodipine, hold promise, but further controlled trials are required before they can be introduced into the therapeutic repertoire of HF management.

Pharmacotherapy of congestive heart failure. Currently used and experimental drugs

A survey is given of the currently used therapeutics in the treatment of chronic congestive heart failure. Symptomatic treatment is usually performed along the following lines: rest, sodium and fluid restriction to unload the decompensating heart, loop diuretics, angiotensin-converting enzyme inhibitors or other vasodilators; inotropic agents to improve the heart's mechanical performance; attempts to counteract the neuro-endocrine compensatory mechanisms, that is the activated sympathetic nervous and renin-angiotensin-aldosterone systems, as well as the rise in vasopressine levels. New insights have been obtained in the effects of cardiac glycosides, which are probably rather based on counteracting the elevated sympathetic neuronal activity than on their weak and uncertain inotropic action. Angiotensin-converting enzyme inhibitors are probably more effective than classical vasodilators owing to their additional interaction with the neuro-endocrine compensatory mechanisms. Ibopamine, a prodrug of epinine, appears to be rather a vasodilator and antagonist of the neuro-endocrine compensatory mechanisms than an inotropic agent. The most important clinical trials addressing the efficacy and adverse reactions to the various aforementioned therapeutics are discussed. New, experimental approaches in the drug treatment of chronic congestive heart failure include beta-blockers, calcium antagonists, vasopressin antagonists and inhibitors of atrial natriuretic peptide degradation.

Treatment of end stage dilated cardiomyopathy

Patients should be referred for cardiac transplantation only after all other means of management of congestive heart failure have been attempted and have been unsuccessful (table 3). An adequate therapeutic trial of conventional and experimental agents including beta blockade and vesnarinone should be completed and be shown to be unsuccessful before transplantation is considered in patients in NYHA class III. Prospective clinical trials need to be completed to define the role of newer therapeutic options. The scarcity of donor organs will probably preclude the use of cardiac transplantation in all patients who may benefit. Alternative methods of cardiac replacement (such as dynamic cardiomyoplasty, permanent implantable mechanical circulatory assistance, and xenografting) must be developed. These methods coupled with better pharmacological treatment will greatly improve the outcome of patients with dilated cardiomyopathy.

Is there a role for positive inotropic agents in congestive heart failure: focus on mortality

Congestive heart failure (CHF) is a common clinical syndrome that may result from a variety of etiologies. Impaired contractility can lead to pump failure and a number of hemodynamic and neurohormonal alterations. Vasodilator therapy improves symptoms and survival in patients with CHF due to systolic dysfunction. Inotropic therapy, on the other hand, has not been shown to improve survival and may even worsen survival. This article reviews the mechanism of action and clinical trials of inotropic therapy in patients with CHF.

Educational status, coronary heart disease, and coronary risk factor prevalence in a rural population of India

OBJECTIVE

To define the association between educational level and prevalence of coronary heart disease and coronary risk factors in India.

DESIGN

Total community cross sectional survey with a doctor administered questionnaire, physical examination, and electrocardiography.

SETTING

A cluster of three villages in rural Rajasthan, western India.

SUBJECTS

3148 residents aged over 20 (1982 men, 1166 women) divided into various groups according to years of formal schooling.

RESULTS

Illiteracy and low educational levels were associated with less prestigious occupations (agricultural and farm labouring) and inferior housing. There was an inverse correlation of educational level with age (rank correlation: mean -0.45, women -0.49). The prevalence of coronary heart disease (diagnosed by electrocardiography) was significantly higher among uneducated and less educated people and showed an inverse relation with education in both sexes. Among uneducated and less educated people there was a higher prevalence of the coronary risk factors smoking and hypertension. Educational level showed a significant inverse correlation with systolic and diastolic blood pressure. Logistic regression analysis with adjustment for age showed that educational level had an inverse relation with prevalence of electrocardiographically diagnosed coronary heart disease (odds ratio: men 0.82, women 0.53), hypertension (men 0.88, women 0.56), and smoking (men 0.73, women 0.65) but not with hypercholesterolaemia and obesity. The inverse relation of coronary heart disease with educational level abated after adjustment for smoking, physical activity, body mass index, and blood pressure (odds ratio: men 0.98, women 0.78).

CONCLUSION

Uneducated and less educated people in rural India have a higher prevalence of coronary heart disease and of the coronary risk factors smoking and hypertension.

Reassessment of digoxin and other low-dose positive inotropes in the treatment of chronic heart failure

Digoxin and other low doses of drugs that have inotropic properties may have an important role to play in the therapy of patients with chronic heart failure. There is convincing evidence that digoxin is effective in relieving the signs and symptoms of heart failure due to systolic dysfunction. While earlier results with some of the other agents have been disappointing, recent data suggest that a reevaluation of these agents is necessary. There is now compelling evidence that lower doses of these agents may be clinically useful without necessarily having any significant hemodynamic effects. The recent experience with vesnarinone is especially promising in showing that therapy with these agents may improve survival in addition to improving clinical status. It is becoming recognized that hemodynamic activity should not necessarily be a prerequisite for clinical utility for those agents. The neuroendocrine and electrophysiologic effects of many of these agents, including digitalis, remain incompletely characterized and may play an important role in their therapeutic benefit. It appears that certain drugs that have inotropic properties may be effective only when their inotropic effects are not readily demonstrated. Further research into the appropriate mechanisms of action and proper dosing of these drugs may lead to a renewed interest in the use of positive inotropes for chronic heart failure.

Nonpharmacologic therapy improves functional and emotional status in congestive heart failure

PURPOSE

To compare the effects of a multimodal nonpharmacologic intervention to digoxin and to placebo in patients with congestive heart failure receiving background therapy with angiotensin-converting enzyme inhibitors.

DESIGN

Randomized, parallel assignment to three treatment groups of 20 patients with congestive heart failure (New York Heart Association Class II and III).

INTERVENTION

Nonpharmacologic treatment program included the following: (1) graduated exercise training, three to five times per week; (2) structured cognitive therapy and stress management; and (3) dietary intervention aimed at salt reduction and weight reduction in the overweight. Digoxin was titrated to achieve a blood level between 0.8 and 2.0 ng/ml. Placebo and digoxin were administered in a randomized, double-blind fashion.

RESULTS

Echocardiographic ejection fraction improved (p < 0.05) in the digitalis group (change = +4.4 +/- 6.5) compared with both placebo (change = -3.2 +/- 3.9) and nonpharmacologic therapy (change = -3.2 +/- 3.9). The nonpharmacologic treatment program was well tolerated by all patients and resulted in significant improvement (p < 0.05) in exercise tolerance (digoxin = +51 +/- 50 s, placebo = +91 +/- 76, nonpharmacologic therapy = +182 +/- 139), as well as Beck Depression Inventory score (digoxin = +1.2 +/- 4.4, placebo = +2.0 +/- 4.2, nonpharmacologic therapy = -5.0 +/- 4.2), Hamilton Scale scores of anxiety (digoxin = +3.0 +/- 6.8, placebo = +6.0 +/- 2.6, nondrug therapy = -5.2 +/- 5.4), and depression (digoxin = +1.0 +/- 4.9, placebo = +5.0 +/- 5.0, nonpharmacologic therapy = -6.6 +/- 10.1). In addition, weight loss was significantly greater with nonpharmacologic therapy (digoxin = +0.32 +/- 1.76 kg; placebo = -1.35 +/- 1.44 kg; nonpharmacologic therapy = -4.37 +/- 4.50 kg) compared with both digoxin and placebo.

CONCLUSIONS

Nonpharmacologic therapy improved functional capacity, body weight, and mood state in patients with congestive heart failure. In contrast, digoxin improved ejection fraction without corresponding changes in exercise tolerance or quality of life.

Role of patient compliance in clinical pharmacokinetics. A review of recent research

Until 1986 to 1987, the estimation of patient compliance with prescribed drug regimens in ambulatory care relied on methods that were biased either by their subjectivity or by the improvement in compliance that commonly occurs during the day or two prior to a scheduled examination, so called 'white-coat compliance'. In 1986 to 1987, 2 objective methods were developed: electronic monitoring and low-dose, slow-turnover chemical markers (digoxin or phenobarbital [phenobarbitone]) incorporated into dosage forms. While neither method is without limitations, both have enabled major advances in the understanding of patients' compliance with dosage regimens and, thus, the spectrum of drug exposure in ambulatory care. The new methods have also triggered not only a revival of interest in patient compliance and its determinants, but also new statistical approaches to interpreting the clinical correlates of widely variable drug administration, and thus drug exposure, in drug trials. The marker methods prove dose ingestion during the 3 to 7 days prior to blood sampling, but do not reveal the timing of doses. The electronic monitoring methods, i.e. time and date-stamping microcircuitry incorporated into drug packages, provide a continuous record of timing of presumptive doses throughout periods of many months, but do not prove dose ingestion. The electronic record has been judged robust enough to detect certain types of investigator fraud, and to support modelling projections of the complete time course of the plasma drug concentration during a trial. Both marker and electronic methods show that the predominant errors are those of omission, i.e. delays or omissions of scheduled doses. Patient interviews, diaries, and counts of returned, untaken doses have been shown by both marker and electronic monitoring methods to consistently and substantially to overestimate compliance. Monitoring of plasma drug concentrations also overestimates compliance, because white-coat compliance is prevalent, and the pharmacokinetic turnover of most drugs is rapid enough that measured concentrations of drug in plasma reflect only drug administration during the period of white-coat compliance. Thus, compliance is a great deal poorer in clinical trials than has been revealed by the older methods. The long-standing underestimation of poor compliance in drug trials has many implications for the interpretation of drug trials, for optimal dose estimation, for the interpretation of failed drug therapy, and for accurate labelling of prescription drugs.

Optimizing the treatment of heart failure

The introduction of new drugs, and a re-evaluation of older drugs, have radically changed the pharmacological management of heart failure. Angiotensin converting enzyme (ACE) inhibitors, digitalis, diuretics and the combination of nitrates and hydralazine are now used. The first Cooperative North Scandinavian Enalapril Survival Study (CONSENSUS I) and the second Vasodilator therapy in Heart Failure Trial (V-HeFT II) have demonstrated that patients with severe or advanced heart failure should be treated with ACE inhibitors, digitalis and diuretics (other vasodilators can be used if ACE inhibitors are contraindicated) to improve symptoms and duration of life. The Studies Of Left Ventricular Dysfunction (SOLVD) and the Munich Heart Failure trial have shown that patients with mild heart failure should be treated with ACE inhibitors. However, data from several large clinical registries suggest that only 40% of patients with heart failure are being given ACE inhibitors perhaps through fear of serious renal damage or hypotension; these fears are unfounded. Patients with anterior myocardial infarcts and reduced left ventricular function also benefit from ACE inhibitors. The fourth International Study of Infarct Survival (ISIS 4) and results from the Gruppo Italiano per Io Studio della Sopravvivenza nell'Infarto miocardico 3 (GISSI 3) have indicated that patients with acute myocardial infarction benefit from early ACE inhibitor therapy and that survival is increased. Heart failure treatment can be optimized by establishing a disease etiology and stressing the need to restrict dietary sodium. ACE inhibitors should be used for depressed left systolic ventricular function, including patients in New York Heart Association class I heart failure.(ABSTRACT TRUNCATED AT 250 WORDS)

Incidence of hospitalization for digitalis toxicity among elderly Americans

OBJECTIVE

To document the prevalence of digitalis use and the incidence of hospitalization caused by digitalis toxicity.

DESIGN

Observational cohort followed for 6 years.

SETTING

Urban community.

PARTICIPANTS

Persons were eligible if they were (1) enrolled in the Yale Health and Aging Project and (2) using digitalis when interviewed in 1982 or 1985. The Project comprises a sample of noninstitutionalized persons aged 65 years and over living in New Haven, Connecticut.

METHODS

Between 1982 and 1988 when a Project participant was hospitalized in New Haven, a researcher reviewed the medical record and coded up to 16 International Classification of Diseases-Class 9 (ICD-9) diagnoses. To identify hospitalizations caused by digitalis, we reexamined records with ICD-9 codes suggesting toxicity. We confirmed the admission illness was an adverse drug reaction with a decision algorithm.

RESULTS

The prevalence of digitalis use was 13% in 1982 and 12% in 1985. The incidence of hospitalization caused by definite or probable toxicity was 4.2% (95% confidence interval = 0.3% to 8.1%) over 6 years. Manifestations of toxicity were malaise or gastrointestinal symptoms (two patients) and heart block plus malaise or gastrointestinal symptoms (six patients). Use of quinidine was associated (P < .05) with toxicity.

CONCLUSION

Knowledge about the incidence of severe, morbid toxicity may help clinicians estimate and compare the risks and benefits of digitalis and alternate therapies.

Digoxin is effective, but is it safe?

In the last 15 years several double-blind, placebo-controlled clinical trials have unequivocally shown that digitalis decreases symptoms of cardiac failure, results in a reduction in the need for hospitalization for treatment of congestive heart failure, and improves cardiac function. The major unresolved question concerning digitalis use is its safety. There are experimental data and clinical evidence that digitalis use may be associated with an increased mortality, particularly in the first year or two after an acute myocardial infarction. This increased mortality appears to be present even after adjustment for predictor covariants. This conclusion depends on the ability of statistical methods to account for differences in comorbidity. Since the question of digitalis safety remains after myocardial infarction, the physician should carefully examine the indications for administration of digitalis. More than the usual surveillance is required during chronic digitalis administration.

Medical advances in the treatment of congestive heart failure

The increased incidence and prevalence of congestive heart failure place a high priority on novel treatment strategies. Left ventricular ejection fraction remains the single most valuable measurement providing both diagnostic and prognostic insights. The most systematic approach to heart failure involves an objective assessment of functional disability, to include exercise tests such as a 6-minute walk under standardized conditions. Left ventricular dysfunction incites a host of neurohumoral compensations that are of fundamental importance in the heart failure syndrome expression. Both vasoconstrictor and vasodilator neurohormones are stimulated and provide new therapeutic opportunities. The therapeutic approach to heart failure begins with a strong emphasis on prevention, patient education, and self-participation in therapy with respect to both its monitoring and adjustment. Diuretics remain a mainstay of therapy but, in the face of severe heart failure, may become ineffectual, requiring constant infusion of loop-active diuretics, combination diuretics, or diuretics in association with concomitant low-dose dopamine infusion. Vasodilator therapy has been an important advance: combination hydralazine and nitrate therapy was initially shown to be efficacious in improving survival, and more recently, angiotensin-converting enzyme (ACE) inhibitors, in the form of enalapril, have shown incremental benefit on survival over this combination. Interestingly, there is now evidence from both SOLVD and SAVE to demonstrate an unexpected and, as yet, unexplained reduction in the frequency of both unstable angina and myocardial infarction. Although, on balance, the weight of evidence concerning the long-term efficacy of inotropic agents has been disappointing, especially as it relates to their unfavorable effects on survival, recent information on vesnarinone, an agent with a complex and diversified mechanism of action, suggests that with appropriate doses, improved symptoms and survival are possible. A substantial amount of new information from randomized placebo-controlled trials attests to the symptomatic relief, hemodynamic improvement, and gain in exercise performance achieved by digoxin. A long-term survival study is ongoing to assess its effects on mortality. beta-Blockers, especially metoprolol, appear beneficial in some patients with heart failure, possibly related to their reduction in sympathetic nervous activity and restoration of beta-receptor population, with resultant improved contractile performance, enhanced myocardial relaxation, and overall increase in cardiac efficiency. Based on available evidence, the best contemporary approach to treatment involves the use of ACE inhibitors coupled with diuretic therapy, either continuous or intermittent, to relieve central or peripheral congestion. The addition of digoxin or a hydralazine nitrate combination is a logical next step, with commencement of low-dose beta-blocker a reasonable option.(ABSTRACT TRUNCATED AT 400 WORDS)

Digoxin in heart failure: implications of recent trials

Although supported by 2 centuries of anecdotal clinical evidence, the safety and efficacy of the cardiac glycosides for the treatment of congestive heart failure due to systolic ventricular dysfunction had never been rigorously examined by prospective clinical trials until the past decade. A reevaluation of the appropriate role of these drugs in modern cardiovascular pharmacology was prompted by the introduction in the 1970s of new classes of drugs for the treatment of congestive heart failure and supraventricular arrhythmias. Concurrently, several reports appeared, questioning the routine prescription of digoxin for the treatment of heart failure, particularly in patients in sinus rhythm. The majority of clinical trials published since 1980, most of which examined patients with New York Heart Association class II and III congestive heart failure, indicate that digoxin with or without concomitant administration of a vasodilator lessens symptoms and reduces the morbidity associated with congestive heart failure, particularly in patients with more advanced symptoms and ventricular dysfunction. The data on efficacy are less clear in support of the routine prescription of digoxin in the treatment of mild (class I and II) congestive heart failure. Although most recent trials attest to the relative safety and efficacy of digoxin in patients with congestive heart failure whose serum levels are maintained between 1 and 2 ng/ml, there is no conclusive evidence as yet that cardiac glycosides improve survival, as has been documented for vasodilators and, in particular, angiotensin-converting enzyme inhibitors. The National Institutes of Health-sponsored Digitalis Investigators Group (DIG) trial now underway should provide an answer to this question within the next few years.

Randomized study assessing the effect of digoxin withdrawal in patients with mild to moderate chronic congestive heart failure: results of the PROVED trial. PROVED Investigative Group

OBJECTIVES

The purpose of this study was to determine whether digoxin is effective in patients with chronic, stable mild to moderate heart failure.

BACKGROUND

Digoxin has been a traditional therapy in heart failure, but methodologic limitations in earlier studies have prevented definitive conclusions regarding its efficacy.

METHODS

Withdrawal of digoxin (placebo group, n = 46) or its continuation (digoxin group, n = 42) was performed in a prospective, randomized, double-blind, placebo-controlled multicenter trial of patients with chronic, stable mild to moderate heart failure secondary to left ventricular systolic dysfunction who had normal sinus rhythm and were receiving long-term treatment with diuretic drugs and digoxin.

RESULTS

Patients withdrawn from digoxin therapy showed worsened maximal exercise capacity (median change in exercise time -96 s) compared with that of patients who continued to receive digoxin (change in exercise time +4.5 s) (p = 0.003). Patients withdrawn from digoxin therapy showed an increased incidence of treatment failures (p = 0.039) (39%, digoxin withdrawal group vs. 19%, digoxin maintenance group) and a decreased time to treatment failure (p = 0.037). In addition, patients who continued to receive digoxin had a lower body weight (p = 0.044) and heart rate (p = 0.003) and a higher left ventricular ejection fraction (p = 0.016).

CONCLUSIONS

These data provide strong evidence of the clinical efficacy of digoxin in patients with normal sinus rhythm and mild to moderate chronic heart failure secondary to systolic dysfunction who are treated with diuretics.