Digoxin and Mortality in Patients With Atrial Fibrillation

Meta-Analysis of Effects of Digoxin on Survival in Patients with Atrial Fibrillation or Heart Failure: An Update

In 2015, 3 independent meta-analyses raised concerns about digoxin therapy being associated with an increased mortality risk in patients with atrial fibrillation (AF) and with heart failure (HF). Although several other studies have been published since then fostering these safety issues, the most recent 2016 European guidelines for AF still recommend this therapy as a class I indication. We performed an updated systematic review and random-effect meta-analysis on publications up to March 2018 reporting data on digoxin associated mortality in subjects with AF or HF. Based on the adjusted survival data of all identified 37 trials comprising a total of 825,061 patients, digoxin use was associated with an increased relative risk of all-cause mortality (hazard ratio [HR] 1.17, 95% confidence interval [CI] 1.05 to 1.29, p <0.01). Treatment with digoxin was associated with an increased mortality risk in the subgroup of patients with AF (n = 627,620, HR 1.23, 95% CI, 1.17 to 1.30, p <0.01), and in the subgroup of patients with HF (n = 197,441, HR 1.11, 95% CI, 1.06 to 1.16, p<0.01). A sensitivity analysis of studies reporting data on new digoxin users (n = 41,687) demonstrated an even higher risk for all-cause mortality compared with patients not receiving cardiac glycosides (HR 1.47, 95% CI, 1.15 to 1.88, p <0.01). In conclusion, this updated meta-analysis confirms that digoxin use is associated with increased mortality in patients with AF or HF.

Clinical Use of Digitalis: A State of the Art Review

The history of digitalis is rich and interesting, with the first use usually attributed to William Withering and his study on the foxglove published in 1785. However, some knowledge of plants with digitalis-like effects used for congestive heart failure (CHF) was in evidence as early as Roman times. The active components of the foxglove (Digitalis purpurea and Digitalis lanata) are classified as cardiac glycosides or cardiotonic steroids and include the well-known digitalis leaf, digitoxin, and digoxin; ouabain is a rapid-acting glycoside usually obtained from Strophanthus gratus. These drugs are potent inhibitors of cellular membrane sodium-potassium adenosine triphosphatase (Na⁺/K⁺-ATPase). For most of the twentieth century, digitalis and its derivatives, especially digoxin, were the available standard of care for CHF. However, as the century closed, many doubts, especially regarding safety, were raised about their use as other treatments for CHF, such as decreasing the preload of the left ventricle, were developed. Careful attention is needed to maintain the serum digoxin level at ≤ 1.0 ng/ml because of the very narrow therapeutic window of the medication. Evidence for benefit exists for CHF with reduced ejection fraction (EF), also referred to as heart failure with reduced EF (HFrEF), especially when considering the combination of mortality, morbidity, and decreased hospitalizations. However, the major support for using digoxin is in atrial fibrillation (AF) with a rapid ventricular response when a rate control approach is planned. The strongest support of all for digoxin is for its use in rate control in AF in the presence of a marginal blood pressure, since all other rate control medications contribute to additional hypotension. In summary, these days, digoxin appears to be of most use in HFrEF and in AF with rapid ventricular response for rate control, especially when associated with hypotension. The valuable history of the foxglove continues; it has been modified but not relegated to the garden or the medical history book, as some would advocate.

Clarity and controversy around rate control in AF, the orphan child in AF therapeutics

The vast majority of clinical arrhythmia-management research over the past couple of decades has focused on catheter-based therapeutic advances. There has been much less emphasis on rate-control strategies; however, the majority of patients with atrial fibrillation (AF) will require some form of rate-control management, making AF rate-control the single most widely used therapeutic component in AF-patients. While the general principles governing AF rate-control have remained largely unchanged, they are often underappreciated. In addition, a number of important controversies make optimal rate-control therapy sometimes difficult to choose. In this review, we aim to address a number of important areas of controversy in the application of AF rate-control, as well as to discuss aspects that are well understood but often underappreciated. Specific areas of focus include the following: (i) heart rate-targets in patients with preserved left-ventricular ejection fraction and concomitant AF; (ii) the clinical implications of differences in pharmacological mechanisms of action between beta-adrenoceptor and Ca²⁺-channel blockers; (iii) controversies regarding the safety and use of digoxin in AF; (iv) the implications cardiac resynchronization therapy for rate-control in AF; and (v) controversies surrounding the benefits of rate-control with beta-blockers in patients with reduced left-ventricular ejection fraction and AF.

How Heart Rate Should Be Controlled in Patients with Atherosclerosis and Heart Failure

PURPOSE OF REVIEW

Resting heart rate is an independent risk factor for all-cause and cardiovascular mortality in patients with heart failure. The main objectives are to discuss the prognosis of heart rate, its association with coronary atherosclerosis, and the modalities of control of the heart rate in sinus rhythm and in the rhythm of atrial fibrillation in patients with chronic heart failure.

RECENT FINDINGS

As a therapeutic option for control heart rate, medications such as beta-blockers, digoxin, and finally ivabradine have been studied. Non-dihydropyridine calcium channel blockers are contraindicated in patients with heart failure and reduced ejection fraction. The influence of the magnitude of heart rate reduction and beta-blocker dose on morbidity and mortality will be discussed. Regarding the patients with heart failure and atrial fibrillation, there are different findings in heart rate control with the use of a beta-blocker. Patients eligible for ivabradine have clinical benefits and increased ejection fraction. Vagal nerve stimulation has low efficacy for the control of heart rate. Complementary therapies such as tai chi and yoga showed no effect on heart rate. In this review, we discuss the main therapeutic options for the control of heart rate in patients with atherosclerosis and heart failure. More research is needed to examine the effects of therapeutic options for heart rate control in different population types, as well as their effects on clinical outcomes and impact on morbidity and mortality.

Is There Still a Role for Digoxin in the Management of Atrial Fibrillation?

PURPOSE OF REVIEW

A number of recent observational analyses have assessed clinical outcomes associated with digoxin use in patients with atrial fibrillation. In this review, we review these data and provide suggestions on the contemporary use of digoxin in patients with atrial fibrillation as supported by the recent evidence.

RECENT FINDINGS

Observational data from clinical trials and registries have provided variable results on the safety and efficacy of chronic digoxin use in patients with atrial fibrillation. In general, results have been consistent with an associated increase in adverse clinical outcomes with digoxin use in atrial fibrillation patients without heart failure. In atrial fibrillation patients with heart failure, while the weight of evidence suggested an associated risk with digoxin therapy, the results are inconsistent. In patients with atrial fibrillation without heart failure, digoxin should generally be avoided. In atrial fibrillation patients with heart failure, digoxin should generally be reserved for patients that do not achieve adequate rate control or are not tolerant of other rate control therapies.

Atrial Fibrillation Ablation in Patients with Heart Failure: One Size Does Not Fit All

Atrial fibrillation (AF) is common in patients with heart failure and is associated with poorer clinical outcomes compared with patients with heart failure alone. Recent evidence has challenged previous treatment paradigms in which rate control was considered equivalent to rhythm control in this population. Catheter ablation has emerged as a safe and effective treatment strategy in selected patients and overcomes the issues of limited efficacy and drug toxicities associated with pharmacological rhythm control. Numerous studies have explored the benefits of catheter ablation in patients with heart failure, but these have included heterogeneous patient cohorts and variable ablation strategies. This state-of-the-art review explores the evidence from these trials and examines the need for tailored, patient-specific strategies for AF ablation in patients with heart failure.

Role of ivabradine and heart rate lowering in chronic heart failure: guideline update

INTRODUCTION

This review summarizes the current management of heart failure (HF) in patients with reduced ejection fraction and the potential role of heart rate lowering agents in select populations, as recommended in the updated guidelines. Areas covered: PubMed was searched for studies that evaluated the role of heart rate lowering or ivabradine in HF management. Expert commentary: Targeting heart rate may offer benefit when added to renin-angiotensin aldosterone antagonists, and beta-blockers. Ivabradine is a heart rate lowering agent that acts on the funny current (I_f) in the sinoatrial node, thereby reducing heart rate without directly affecting cardiac contraction and relaxation. Clinical data from a phase III trial demonstrated that ivabradine reduced the composite end point of cardiovascular death or hospital admission for worsening systolic HF, while maintaining an acceptable safety profile in patients receiving standard of care therapy. These data, in addition to more recently published guidelines, suggest ivabradine as a promising new treatment option for lowering heart rate after optimizing standard therapy in select patients with chronic HF.

Risk Factors, Co-Morbidities and Treatment of In-Hospital Patients with Atrial Fibrillation in Bulgaria

Background and objectives: Atrial fibrillation (AF) is the most common arrhythmia worldwide and a major risk factor for cardiovascular complications. Our study aimed to investigate the prevalence, risk factors, demographics, co-morbidities and treatment of AF among in-hospital Bulgarian patients. Materials and Methods: A cross-sectional study including 1027 consecutive patients (n = 516, 50.2% males) with a mean age of 67.6 ± 11.3 years, hospitalized for any reason from 1 May until 31 December 2016 in one of the largest internal clinics in Bulgaria, was carried out. Results: Atrial fibrillation was diagnosed in 634 (61.7%) patients. The prevalence of modifiable AF risk factors was as follows: heart failure, 98.9%; arterial hypertension (HTN), 93.5%; valvular heart disease, 40.9%; chronic lung disease, 26.7%; type 2 diabetes mellitus, 24.9%; thyroid disease, 16.9%; and ischemic heart disease, 11.2%. Univariate logistic regression analysis identified the following risk factors with strongest impact on AF: left ventricular ejection fraction <40% (odds ratio (OR) = 1.951, 95% confidence interval (CI) 1.208–3.151), valvular heart disease (OR = 1.926, 95% CI 1.134–3.862), left ventricular ejection fraction 40–49% (OR = 1.743, 95% CI 1.248–3.017), HTN (OR = 1.653, 95% CI 1.092–3.458). History of ischemic stroke was present in 14.4% of the patients with AF. Oral antithrombotic drugs were prescribed to 85.7%: direct oral anticoagulants to 37.9%, vitamin K antagonists to 43.2%, and antiplatelets to 4.6%. Heart rate control medications and antiarrhythmics were prescribed to 75.4% and 40.2%, respectively. Conclusions: Atrial fibrillation was highly prevalent among our study population. Reduced and mid-range left ventricular ejection fraction, valvular heart disease, and HTN were the risk factors with the strongest association with AF. Although a large number of our AF patients were administered antithrombotic treatment, the prescription rate of oral anticoagulants should be further improved.