Digoxin

Peripartum Cardiomyopathy

Peripartum cardiomyopathy is a potentially life-threatening pregnancy-associated disease that typically arises in the peripartum period and is marked by left ventricular dysfunction and heart failure. The disease is relatively uncommon, but its incidence is rising. Women often recover cardiac function, but long-lasting morbidity and mortality are not infrequent. Management of peripartum cardiomyopathy is largely limited to the same neurohormonal antagonists used in other forms of cardiomyopathy, and no proven disease-specific therapies exist yet. Research in the past decade has suggested that peripartum cardiomyopathy is caused by vascular dysfunction, triggered by late-gestational maternal hormones. Most recently, information has also indicated that many cases of peripartum cardiomyopathy have genetic underpinnings. We review here the known epidemiology, clinical presentation, and management of peripartum cardiomyopathy, as well as the current knowledge of the pathophysiology of the disease.

Is foxglove effective in heart failure?

BACKGROUND

Digoxin is the oldest known treatment for heart failure (HF) and has been demonstrated to reduce admissions for worsening heart failure in a large randomized trial recruiting patients in sinus rhythm with heart failure and ejection fraction <45%. This study forms the basis for current international guidelines recommending that digoxin should be considered in patients with symptomatic HF despite optimal doses of angiotensin-converting enzyme inhibitors/angiotensin receptor blockers, β-blockers, and mineralocorticoid receptor antagonists in addition to device therapy, if indicated. However, digoxin predates mortality reducing HF therapies, and this article reviews the historical and recent data.

METHODS

Multiple PubMed searches were performed including, but not limited to, the search terms "digoxin," "heart failure," "efficacy," "treatment," "side-effects," "morbidity," "mortality," and "arrythmia." Articles were excluded if not relevant, not in English or without abstract. Reference lists of relevant articles were manually searched for further references. Due to the large number of articles retrieved, a selection was reviewed based on the authors' best judgement.

RESULTS

Three randomized controlled trials and three large contemporary observational reports of digoxin therapy in heart failure and sinus rhythm were retrieved. Other studies were noted that included patients with heart failure and atrial fibrillation, which were also reviewed.

CONCLUSION

Definitive randomized evidence of digoxin efficacy as add-on therapy in HF is lacking because most landmark trials of modern HF disease modifying agents postdate the randomized studies of digoxin. Furthermore, questions remain regarding the optimum dose of digoxin and there are signals that digoxin may be harmful in some patients with HF. All contemporary data for digoxin in HF are derived from observational studies and the findings are conflicting. Despite two centuries of experience using cardiac glycosides to treat HF, fundamental questions regarding the efficacy and safety of digoxin in HF remain unanswered.

Digoxin in Heart Failure with a Reduced Ejection Fraction: A Risk Factor or a Risk Marker?

Digoxin is one of the oldest compounds used in cardiovascular medicine. Nevertheless, its mechanism of action and most importantly its clinical utility have been the subject of an endless dispute. Positive inotropic and neurohormonal modulation properties are attributed to digoxin, and it was the mainstay of heart failure therapeutics for decades. However, since the institution of β-blockers and aldosterone antagonists as part of modern heart failure medical therapy, digoxin prescription rates have been in free fall. The fact that digoxin is still listed as a valid therapeutic option in both American and European heart failure guidelines has not altered clinicians' attitude towards the drug. Since the publication of original Digitalis Investigation Group trial data, a series of reports based predominately on observational studies and post hoc analyses have raised concerns about the clinical efficacy and long-term safety of digoxin. In the present review, we will attempt a critical appraisal of the available clinical evidence regarding the efficacy and safety of digoxin in heart failure patients with a reduced ejection fraction. The methodological issues, strengths, and limitations of individual studies will be highlighted.

Can medications be safely withdrawn in patients with stable chronic heart failure? systematic review and meta-analysis

BACKGROUND

Heart failure (HF) therapy involves use of multiple medications. There is little guidance on the safety and impact on clinical outcomes of stopping HF medications.

METHODS AND RESULTS

A comprehensive systematic search for studies of drug therapy withdrawal in HF was performed. Meta-analysis of the risk ratio (RR) was performed with the use of the Mantel-Haenszel random effects model for all-cause mortality and cardiovascular outcomes. Twenty-six studies met the inclusion criteria. Studies on withdrawal of renin-angiotensin-aldosterone system (RAAS) inhibitors and beta-blockers in HF are scarce and small, yet show relatively convincingly that such withdrawals have untoward effects on cardiac structure, symptoms, and major outcomes. Meta-analysis of 7 studies of digoxin withdrawal (2,987 participants) without background beta-blocker showed increased HF hospitalizations (RR 1.30, 95% confidence interval [CI] 1.16-1.46; P < .0001), but no impact on all-cause mortality (RR 1.00, 95% CI 0.90-1.12; P = .06) nor reduction in all-cause hospitalization (RR 1.03, 95% CI 0.98-1.09; P = .27). Diuretic withdrawal trials demonstrated an ongoing need for these agents in chronic HF. Studies in peripartum cardiomyopathy showed that medications could be successfully withdrawn after recovery.

CONCLUSION

Current evidence discourages any attempt to discontinue RAAS inhibitors or beta-blockers in patients with stable HF, regardless of clinical and/or echocardiographic status. Formal withdrawal trials of other classes are needed.

The 2013 Annual Autumn Meeting of the British Society of Heart Failure

16th British Society for Heart Failure Annual Autumn Meeting Queen Elizabeth II Conference Centre, London, UK, 28-29 November 2013 The 16th Annual Meeting for the British Society for Heart Failure took place in the impressive surroundings of the Queen Elizabeth II Conference Centre in Westminster (London, UK). Over the two-day conference, more than 700 delegates attended - the largest number to date. Over 40 talks were delivered by some of the world's experts in heart failure. For 2013, the theme was making sense of acute heart failure - a clinical entity which is frequently encountered, poorly understood, and for which there exists virtually no evidence base for treatment.

Resting heart rate and outcomes in patients with cardiovascular disease: where do we currently stand?

BACKGROUND

Data from large epidemiological studies suggest that elevated heart rate is independently associated with cardiovascular and all-cause mortality in patients with hypertension and in those with established cardiovascular disease. Clinical trial findings also suggest that the favorable effects of beta-blockers and other heart rate-lowering agents in patients with acute myocardial infarction and congestive heart failure may be, at least in part, due to their heart rate-lowering effects. Contemporary clinical outcome prediction models such as the Global Registry of Acute Coronary Events (GRACE) score include admission heart rate as an independent risk factor.

AIMS

This article critically reviews the key epidemiology concerning heart rate and cardiovascular risk, potential mechanisms through which an elevated resting heart rate may be disadvantageous and evaluates clinical trial outcomes associated with pharmacological reduction in resting heart rate.

CONCLUSIONS

Prospective randomised data from patients with significant coronary heart disease or heart failure suggest that intervention to reduce heart rate in those with a resting heart rate >70 bpm may reduce cardiovascular risk. Given the established observational data and randomised trial evidence, it now appears appropriate to include reduction of elevated resting heart rate by lifestyle +/- pharmacological therapy as part of a secondary prevention strategy in patients with cardiovascular disease.

Lack of evidence of increased mortality among patients with atrial fibrillation taking digoxin: findings from post hoc propensity-matched analysis of the AFFIRM trial

AIMS

Digoxin is recommended for long-term rate control in paroxysmal, persistent, and permanent atrial fibrillation (AF). While some analyses suggest an association of digoxin with a higher mortality in AF, the intrinsic nature of this association has not been examined in propensity-matched cohorts, which is the objective of the current study.

METHODS AND RESULTS

In Atrial Fibrillation Follow-up Investigation of Rhythm Management (AFFIRM), 4060 patients with paroxysmal and persistent AF were randomized to rate (n = 2027) vs. rhythm (n = 2033) control strategies. Of these, 1377 received digoxin as initial therapy and 1329 received no digoxin at baseline. Propensity scores for digoxin use were estimated for each of these 2706 patients and used to assemble a cohort of 878 pairs of patients receiving and not receiving digoxin, who were balanced on 59 baseline characteristics. Matched patients had a mean age of 70 years, 40% were women, and 11% non-white. During the 3.4 years of the mean follow-up, all-cause mortality occurred in 14 and 13% of matched patients receiving and not receiving digoxin, respectively [hazard ratio (HR) associated with digoxin use: 1.06; 95% confidence interval (CI): 0.83-1.37; P = 0.640]. Among matched patients, digoxin had no association with all-cause hospitalization (HR: 0.96; 95% CI: 0.85-1.09; P = 0.510) or incident non-fatal cardiac arrhythmias (HR: 0.90; 95% CI: 0.37-2.23; P = 0.827). Digoxin had no multivariable-adjusted or propensity score-adjusted associations with these outcomes in the pre-match cohort.

CONCLUSIONS

In patients with paroxysmal and persistent AF, we found no evidence of increased mortality or hospitalization in those taking digoxin as baseline initial therapy.

Digoxin in advanced heart failure patients: a question of rhythm

BACKGROUND

The impact of digoxin on outcomes of patients with advanced heart failure (HF) remains uncertain and its effect may be different for patients in atrial fibrillation (AF) or sinus rhythm (SR).

OBJECTIVES

To determine the impact of digoxin on outcomes of advanced HF patients and to assess whether prognosis differs in patients in AF and SR.

METHODS

A total of 268 consecutive patients admitted to an intensive care unit with decompensated HF were evaluated. Patients were divided into two groups: A - patients with AF (n=89), and B - patients in SR (n=179). For each group we compared patients medicated and not medicated with digoxin. A mean follow-up of 3.3 years was performed.

RESULTS

Addition of digoxin to contemporary standard HF therapy showed no impact on mortality of patients in group B (all-cause mortality in follow-up: 19.1% vs. 22.5%, p=0.788). Regarding group A, we observed significantly lower medium-term mortality for patients on digoxin therapy (18.6% vs. 46.6%, p=0.048). Digoxin therapy did not influence readmissions for decompensated HF. Among AF patients, no differences were found regarding demographic, clinical, echocardiographic and laboratory variables between patients medicated and not medicated with digoxin.

CONCLUSIONS

Digoxin therapy may improve the prognosis of advanced HF patients with AF under optimal medical therapy. However, no benefit of digoxin was demonstrated for patients in SR. These results may help to improve patient selection for digoxin therapy.

Non-compliance with digoxin in patients with heart failure and/or atrial fibrillation: a systematic review and meta-analysis of observational studies

BACKGROUND

Digoxin is highly potent and efficacious for treatment of heart failure (HF) and/or atrial fibrillation (AF) yet compliance is often poor.

AIMS

To examine prevalence rates of non-compliance with digoxin; variations between clinical settings, types of non-compliance and methods of detection; and potential factors influencing non-compliance with digoxin.

METHODS

This was a systematic review and meta-analysis of prospective observational studies of non-compliance with digoxin in patients with HF and/or AF, published in English. The studies were identified through these bibliographic databases: MEDLINE, EMBASE, CINAHL, IPA and Cochrane CENTRAL. Subgroup analysis examined the influence of clinical settings, types of non-compliance and methods of detection.

RESULTS

Ten studies met the inclusion criteria, comprising 1841 patients with HF and/or AF. The corresponding prevalence rates of non-compliance for outpatients, after hospital discharge and inpatients were 43.1% (interquartile range [IQR] 29-48%), 25% (95% confidence interval [CI] 12-37%) and 4.5%, respectively. In patients with HF and AF co-morbidities, the prevalence rate of non-compliance with digoxin was 38.7% (IQR 27-46%); the corresponding prevalence rates of overdosing and underdosing were 33.04% (IQR 22-49%) and 33.8% (95% CI 25-42%), respectively. Rates varied depending on the methods of detecting non-compliance. Regularity of prescribed dose, diuretic use, coronary artery bypass, implantable cardioverter-defibrillator, number of office visits and pill boxes demonstrated strong associations with non-compliance with digoxin.

CONCLUSIONS

Non-compliance with digoxin is prevalent among patients with HF and/or AF. A better understanding of the factors influencing compliance and improved intervention strategies are necessary to increase digoxin compliance.