Digitalis: a dangerous drug in atrial fibrillation? An analysis of the SPORTIF III and V data

Resibufogenin Targets the ATP1A1 Signaling Cascade to Induce G2/M Phase Arrest and Inhibit Invasion in Glioma

Resibufogenin (RB) is a major active ingredient in the traditional Chinese medicine Chansu and has garnered considerable attention for its efficacy in the treatment of cancer. However, the anticancer effects and underlying mechanisms of RB on glioblastoma (GBM) remain unknown. Here, we found that RB induced G2/M phase arrest and inhibited invasion in a primary GBM cell line, P3#GBM, and two GBM cell lines, U251 and A172. Subsequently, we demonstrated that RB-induced G2/M phase arrest occurred through downregulation of CDC25C and upregulation of p21, which was caused by activation of the MAPK/ERK pathway, and that RB inhibited GBM invasion by elevating intercellular Ca²⁺ to suppress the Src/FAK/Paxillin focal adhesion pathway. Intriguingly, we confirmed that upon RB binding to ATP1A1, Na⁺-K⁺-ATPase was activated as a receptor and then triggered the intracellular MAPK/ERK pathway and Ca²⁺-mediated Src/FAK/Paxillin focal adhesion pathway, which led to G2/M phase arrest and inhibited the invasion of GBM cells. Taken together, our findings reveal the antitumor mechanism of RB by targeting the ATP1A1 signaling cascade and two key signaling pathways and highlight the potential of RB as a new class of promising anticancer agents.

Digoxin Impact on Heart Failure Patients with Atrial Fibrillation

BACKGROUND

Digoxin is a cardiac glycoside, derived from the plant Digitalis purpurea. For many years digitalis has been widely used in the treatment of heart failure (HF), owing to its cardiotonic and neurohormonal effects and atrial fibrillation (AF), due to its parasympathomimetic effect on the AV node.

OBJECTIVE

The aim of this paper is to evaluate the available evidence on the safety and efficacy of digoxin in patients with HF and AF, by reviewing the pertinent literature.

METHODS

We conducted a PubMed/MEDLINE and SCOPUS search to evaluate the currently available evidence on the administration of digoxin and its association with all-cause mortality risk in patients with AF and HF.

RESULTS

Several observational analyses of clinical trials and meta-analyses have shown conflicting results on the safety and efficacy of digoxin administration in patients with AF and HF. According to these results, digoxin should be avoided in patients without HF, as it is associated with worse outcomes. On the other hand, in patients with AF and HF digoxin should be used with caution.

CONCLUSION

The impact of digoxin on all-cause mortality and adverse effects in these patients remains unclear based on the current evidence. More trials at low risk of bias evaluating the effects of digoxin are needed.

Effect of Digoxin Therapy on Mortality in Patients With Atrial Fibrillation: An Updated Meta-Analysis

Background: Whether digoxin is associated with increased mortality in atrial fibrillation (AF) remains controversial. We aimed to assess the risk of mortality and clinical effects of digoxin use in patients with AF.

Methods: PubMed, Embase, and the Cochrane library were systematically searched to identify eligible studies comparing all-cause mortality of patients with AF taking digoxin with those not taking digoxin, and the length of follow-up was at least 6 months. Hazard ratios (HRs) with 95% confidence intervals (CIs) were extracted and pooled.

Results: A total of 29 studies with 621,478 patients were included. Digoxin use was associated with an increased risk of all-cause mortality in all patients with AF (HR 1.17, 95% CI 1.13–1.22, P < 0.001), especially in patients without HF (HR 1.28, 95% CI 1.11–1.47, P < 0.001). There was no significant association between digoxin and mortality in patients with AF and HF (HR 1.06, 95% CI 0.99–1.14, P = 0.110). In all patients with AF, regardless of concomitant HF, digoxin use was associated with an increased risk of sudden cardiac death (SCD) (HR 1.40, 95% CI 1.23–1.60, P < 0.001) and cardiovascular (CV) mortality (HR 1.27, 95% CI 1.08–1.50, P < 0.001), and digoxin use had no significant association with all-cause hospitalization (HR 1.13, 95% CI 0.92–1.39, P = 0.230).

Conclusion: We conclude that digoxin use is associated with an increased risk of all-cause mortality, CV mortality, and SCD, and it does not reduce readmission for AF, regardless of concomitant HF. Digoxin may have a neutral effect on all-cause mortality in patients with AF with concomitant HF.

Systematic Review Registration:https://www.crd.york.ac.ukPROSPERO.

Influence of digoxin on mortality in patients with atrial fibrillation: Overview of systematic reviews

Once a routine part of atrial fibrillation (AF) management, digoxin use has declined. Likely hastening this decline are findings from several studies and systematic reviews identifying a potential association between digoxin use and all-cause mortality in AF populations. However, inconsistency exists within some of these studies potentially leading to confusion among clinicians. To critically evaluate the current literature to contextualize the associations between digoxin and mortality risk in patients with AF by performing an overview of systematic reviews. We searched MEDLINE, Cochrane Central Database of Systematic Reviews, and SCOPUS from their earliest date through October 12, 2020, to identify systematic reviews (SRs) that included studies enrolling patients with AF or atrial flutter and evaluated the association between digoxin use and all-cause mortality. We used the AMSTAR 2 tool to assess the risk of bias for each included SR. Results from reviews are qualitatively synthesized. Our search identified 10 SRs that met our inclusion criteria. Of the 41 unique AF studies included in these SRs, 41% were cohort studies, 29% were post hoc analyses of randomized controlled trials (RCTs), 15% were RCTs, and 15% were registry studies. Based on our AMSTAR 2 assessment, the overall confidence in the results of the 10 reviews was rated as "moderate" in three SRs, "low" in three SRs, and "critically low" in the rest. Except for one review, each included SR shows that digoxin use in AF is associated with a 15 to 38% higher risk of all-cause mortality. This association may be greater when AF-only populations are considered compared with a mix of AF and heart failure populations. Serum digoxin concentration (SDC) data were infrequently considered, but available data suggested a greater association between increasing SDC and all-cause mortality. This overview of reviews found general consistency regarding the association between digoxin use and higher all-cause mortality in AF populations. However, heterogeneity exists among and between SRs and an unmet need exists for additional study in a RCT setting with close monitoring and reporting of SDC to better inform clinical practice.

Association of digoxin with mortality in patients with advanced chronic kidney disease: A population-based cohort study

Digoxin is commonly prescribed for heart failure and atrial fibrillation, but there is limited data on its safety in patients with chronic kidney disease (CKD). We conducted a population-based cohort study using the pre-end stage renal disease (ESRD) care program registry and the National Health Insurance Research Database in Taiwan. Of advanced CKD patient cohort (N = 31,933), we identified the digoxin user group (N = 400) matched with age and sex non-user group (N = 2,220). Multivariable Cox proportional hazards and sub-distribution hazards models were used to evaluate the association between digoxin use and the risk of death, cardiovascular events (acute coronary syndrome, ischemic stroke, or hemorrhagic stroke) and renal outcomes (ESRD, rapid decline in estimated glomerular filtration rate-eGFR, or acute kidney injury). Results showed that all-cause mortality was higher in the digoxin user group than in the non-user group, after adjusting for covariates (adjusted hazard ratio, aHR 1.63; 95% CI 1.23-2.17). The risk for acute coronary syndrome (sub-distribution hazard ratio, sHR 1.18; 95% CI 0.75-1.86), ischemic stroke (sHR 1.42; 95% CI 0.85-2.37), and rapid eGFR decline (sHR 1.00 95% CI 0.78-1.27) was not significantly different between two groups. In conclusion, our study demonstrated that digoxin use was associated with increased mortality, but not cardiovascular events or renal function decline in advanced CKD patients. This finding warns the safety of prescribing digoxin in this population. Future prospective studies are needed to overcome the limitations of cohort study design.

Digoxin-mortality: randomized vs. observational comparison in the DIG trial

AIMS

The Digitalis Investigation Group (DIG) trial, the only large randomized trial of digoxin in heart failure, reported a neutral effect on mortality and a significant reduction in heart failure hospitalizations. Recent observational studies reported increased mortality with digoxin treatment. We present further analyses of the DIG trial displaying the inability to control bias in observational treatment comparisons despite extensive statistical adjustments.

METHODS AND RESULTS

Forty-four percent of the 6800 patients in the DIG trial had been treated with digoxin before randomization, and half of them were randomly withdrawn from digoxin treatment. We contrast the main randomization-based result of the DIG trial with the observational non-randomized comparison of patients pre-treated or not pre-treated with digoxin. Mortality [hazard ratio (HR) 1.22, 95% confidence interval (CI) 1.12-1.34; P < 0.001] and heart failure hospitalizations (HR 1.47, 95% CI 1.33-1.61; P < 0.001) were significantly higher in patients pre-treated with digoxin even after adjustment for baseline population differences. The higher risks for both outcomes in those who had previously received digoxin persisted even if they received placebo during the trial (HR 1.24, 95% CI 1.10-1.40; P < 0.001). This sharply contradicts the neutral effect on mortality and the significant reduction in heart failure hospitalizations observed in the randomized comparison.

CONCLUSION

Prescription of digoxin is an indicator of disease severity and worse prognosis, which cannot be fully accounted for by covariate adjustments in the DIG trial where patients were well-characterized. It is unlikely that weaker research approaches (observational studies of administrative data or registries) can provide more reliable estimates of the effects of cardiac glycosides.

The 2020 Canadian Cardiovascular Society/Canadian Heart Rhythm Society Comprehensive Guidelines for the Management of Atrial Fibrillation

The Canadian Cardiovascular Society (CCS) atrial fibrillation (AF) guidelines program was developed to aid clinicians in the management of these complex patients, as well as to provide direction to policy makers and health care systems regarding related issues. The most recent comprehensive CCS AF guidelines update was published in 2010. Since then, periodic updates were published dealing with rapidly changing areas. However, since 2010 a large number of developments had accumulated in a wide range of areas, motivating the committee to complete a thorough guideline review. The 2020 iteration of the CCS AF guidelines represents a comprehensive renewal that integrates, updates, and replaces the past decade of guidelines, recommendations, and practical tips. It is intended to be used by practicing clinicians across all disciplines who care for patients with AF. The Grading of Recommendations, Assessment, Development and Evaluations (GRADE) system was used to evaluate recommendation strength and the quality of evidence. Areas of focus include: AF classification and definitions, epidemiology, pathophysiology, clinical evaluation, screening and opportunistic AF detection, detection and management of modifiable risk factors, integrated approach to AF management, stroke prevention, arrhythmia management, sex differences, and AF in special populations. Extensive use is made of tables and figures to synthesize important material and present key concepts. This document should be an important aid for knowledge translation and a tool to help improve clinical management of this important and challenging arrhythmia.

Digoxin-amiodarone Combination is Associated With Excess All-cause Mortality in Patients With Atrial Fibrillation

Combination use of digoxin and other medications might lead to worse outcomes in patients with atrial fibrillation (AF). We sought to investigate whether digoxin-amiodarone combination would lead to worse outcome than digoxin alone in patients with AF. Adult patients with AF and received digoxin treatment from random samples of 1,000,000 individuals covered by the National Health Insurance in Taiwan were included. Baseline characteristics including risk factors and medications were matched by propensity score (PS) in those with and without addition of amiodarone treatment. A total of 5,040 AF patients taking digoxin therapy was included. PS matching identified 1,473 patients receiving digoxin-amiodarone combination and 2,660 patients receiving digoxin with a median follow-up of 1,331 days. Digoxin-amiodarone combination was associated with increased all-cause mortality (adjusted hazard ratio (HR): 1.640, 95% confidence interval (CI): 1.470–1.829, P < 0.001). The risk of mortality increased regardless of duration of combination. Risk of sudden cardiac death was not increased in the combination group (HR: 1.304, 95% CI: 1.049–1.622, P = 0.017). Death due to non-arrhythmic cardiac disease, cerebrovascular disease, and other vascular disease were higher in the combination group than the digoxin group. In conclusion, in patients with AF, digoxin-amiodarone combination therapy is associated with excess mortality than digoxin alone.

Association Between Digoxin Use and Adverse Outcomes Among Patients in the Chinese Atrial Fibrillation Registry

INTRODUCTION

Digoxin is widely used in patients with atrial fibrillation (AF), but its association with adverse outcomes remains controversial.

OBJECTIVE

We aimed to assess the association between digoxin and adverse outcomes in Chinese patients with AF.

METHODS

We used data from the Chinese Atrial Fibrillation Registry, a prospective, multicenter, hospital-based registry study involving 31 hospitals. In total, 10,472 eligible patients with AF, enrolled from August 2011 to December 2016, were included in this study. The association between digoxin use and all-cause mortality, cardiovascular death, and cardiovascular hospitalization were investigated using Cox proportional hazards models.

RESULTS

In total, 1152 (11%) patients were treated with digoxin at baseline. Patients receiving digoxin were older (mean age 69.7 vs. 66.5 years) and had a higher heart rate (92.4 vs. 79.7 beats/min). A higher proportion of patients receiving digoxin therapy had a history of heart failure (62.5 vs. 15.6%), diabetes mellitus (34.4 vs. 24.4%), and persistent AF (67.9 vs. 38.4%). Digoxin use was independently associated with increased all-cause mortality (adjusted hazard ratio (aHR) 1.21; 95% confidence interval (CI) 1.02-1.43; p = 0.031), cardiovascular death (aHR 1.25; 95% CI 1.01-1.55; p = 0.043), and cardiovascular hospitalization (aHR 1.21; 95% CI 1.05-1.39; p = 0.007). The associations were also homogeneous across various subgroups except in patients with and without renal dysfunction (p value for interaction = 0.029).

DISCUSSION

In this Chinese AF cohort, for patients who had not undergone ablation, digoxin use was associated with a significant increase in adverse outcomes. Although residual confounders may exist, and serum concentrations of digoxin were unavailable, digoxin should be used with caution in clinical practice, and its effects need to be critically evaluated in randomized trials.

CLINICAL TRIAL REGISTRATION

URL: http://www.chictr.org.cn/showproj.aspx?proj=5831. Unique identifier: ChiCTR-OCH-13003729.

Digoxin and prognosis of heart failure in older patients with preserved ejection fraction: Importance of heart rate. Results from an observational and multicenter study

BACKGROUND

The value of digoxin in heart failure (HF) remains controversial, particularly in patients with preserved ejection fraction (HFpEF). This study evaluated the 1-year risk of events after digoxin treatment for acute heart failure (AHF) in patients >70 years old with HFpEF.

METHODS

1833 patients were included in this analysis (mean age, 82 years). The main endpoints were all-cause death and the composite of death and/or HF re-admission within 1 year. Cox regression analysis was used to evaluate the association between digoxin treatment and prognosis.

RESULTS

401 patients received digoxin treatment; of these, 86% had atrial fibrillation. The mean baseline heart rate was 86 ± 22 bpm. At the 1-year follow-up, 375 patients (20.5%) died and 684 (37.3%) presented composite endpoints. Patients treated with digoxin showed higher rates of death (3.21 vs. 2.44 per 10 person-years, p = .019) and composite endpoint (6.72 vs. 5.18 per 10 person-years, p = .003). After multivariate adjustment, digoxin treatment remained associated with increased risks of death (HR = 1.46, 95% CI: 1.16-1.85, p = .001) and the composite endpoint (HR = 1.35, 95% CI: 1.13-1.61, p = .001). A distinctive prognostic effect of digoxin was found across the heart rate continuum; the risks for both endpoints were higher at lower heart rates and neutral at higher heart rates (p of the interactions = 0.007 and 0.03, respectively).

CONCLUSIONS

In older patients with HFpEF discharged after AHF, digoxin treatment was associated with increased mortality and/or re-admission, particularly in patients with lower heart rates.

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.

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.

Overexpression of the Na+ /Ca2+ exchanger influences ouabain-mediated spontaneous Ca2+ activity but not positive inotropy

Administration of digitalis in heart failure (HF) increases quality of life but does not carry a prognostic benefit. Digitalis is an indirect inhibitor of the Na⁺ /Ca²⁺ exchanger (NCX), which is overexpressed in HF. We therefore used the cardiac glycoside ouabain in Ca²⁺ imaging experiments and patch-clamp experiments in isolated ventricular myocytes from nonfailing transgenic NCX overexpressor mice (OE). In field-stimulated myocytes, ouabain (1-100 μm) increased the amplitude of the Ca²⁺ transient in OE and wild-type (WT) similarly. Ouabain-mediated spontaneous Ca²⁺ -activity was significantly more pronounced in OE compared to WT myocytes at higher concentrations (100 μm). Also, at very high concentrations (1000 μm) of ouabain, the number of cells with hypercontraction leading to cell death was higher in OE. Ouabain (10 μm) shortened the action potential duration in both genotypes. Our findings suggest that the proarrhythmic but not the inotropic effects of cardiac glycosides are enhanced by increased NCX expression. This may offer an explanation for the observed lack of prognostic benefit but increased quality of life in HF, which is accompanied by NCX upregulation.

Effect of Chronic Kidney Diseases on Mortality among Digoxin Users Treated for Non-Valvular Atrial Fibrillation: A Nationwide Register-Based Retrospective Cohort Study

PURPOSE

This study investigated the impact of chronic kidney disease on all-causes and cardiovascular mortality in patients with atrial fibrillation treated with digoxin.

METHODS

All patients with non-valvular atrial fibrillation and/or atrial flutter as hospitalization diagnosis from January 1, 1997 to December 31, 2012 were identified in Danish nationwide administrative registries. Cox proportional hazard model was used to compare the adjusted risk of all-causes and cardiovascular mortality among patients with and without chronic kidney disease and among patients with different chronic kidney disease stages within 180 days and 2 years from the first digoxin prescription.

RESULTS

We identified 37,981 patients receiving digoxin; 1884 patients had the diagnosis of chronic kidney disease. Cox regression analysis showed no statistically significant differences in all-causes (Hazard Ratio, HR 0.89; 95% confident interval, CI 0.78-1.03) and cardiovascular mortality (HR 0.88; 95%CI 0.74-1.05) among patients with and without chronic kidney disease within 180 days of follow-up period. No statistically significant differences was found using a 2 years follow-up period neither for all causes mortality (HR 0.90; 95%CI 0.79-1.03), nor for cardiovascular mortality (HR 0.87; 95%CI 0.74-1.02). No statistically significant differences was found comparing patients with and without estimated Glomerular Filtration Rate <30ml/min/1.73m2 and patients with different stages of chronic kidney disease, for all-causes and cardiovascular mortality within 180 days and 2 years from the first digoxin prescription.

CONCLUSIONS

This study suggest no direct effect of chronic kidney disease and chronic kidney disease stages on all-causes and cardiovascular mortality within both 180 days and 2 years from the first digoxin prescription in patients treatment-naïve with digoxin for non-valvular atrial fibrillation.

Digoxin Is Associated With Increased All-cause Mortality in Patients With Atrial Fibrillation Regardless of Concomitant Heart Failure: A Meta-analysis

For decades, digoxin has been widely used to control ventricular rate in atrial fibrillation (AF). However, it remains controversial as to whether digoxin is associated with increased mortality in AF. In this study, we searched relevant studies that were published before December 1, 2014, in PubMed, EMBASE, and the Cochrane central databases. We systematically reviewed the references and performed a meta-analysis of 8 carefully selected studies with 302,738 patients who were included for the final analysis. It was shown that digoxin use was associated with increased risk of all-cause mortality in AF overall [hazard ratio (HR) = 1.375, 95% confidence intervals (CI), 1.201-1.574, P = 0.0001]. Subgroup analysis further revealed that digoxin was associated with increased all-cause mortality in patients with AF, which was complicated by heart failure (HF) (HR = 1.201, CI, 1.074- 1.344, P = 0.001), and in those subjects without HF (HR = 1.172, CI, 1.148-1.198, P = 0.0001). Sensitivity analyses found results to be robust. Our findings indicated that digoxin use was associated with significantly increased all-cause mortality in patients with AF regardless of concomitant HF. We suggest that digoxin should not be preferentially used over other rate control medications in AF.

Digoxin Use and Adverse Outcomes in Patients With Atrial Fibrillation

Digoxin has long been used for rate control in atrial fibrillation (AF); its safety remains controversial.We performed a literature search using MEDLINE (source PubMed, January 1, 1966, to July 31, 2015) and EMBASE (January 1, 1980, to July 31, 2015) with no restrictions. Studies that reported relative risk (RR) estimates with 95% confidence intervals (CIs) for the associations of interest were included. Pooled effect estimates were obtained by using random-effects meta-analysis.Twenty-two studies involving 586,594 patients were identified. Patients taking digoxin, as compared with those who took no digoxin, experienced an increased risk of death from any cause (RR: 1.29[95% CI 1.16-1.43]), even after reported adjustment for propensity scores (RR: 1.28[95% CI 1.18-1.39]). The risk of death was increased with patients with or without heart failure (RR: 1.12[95% CI 1.02-1.23] and RR: 1.26[95% CI 1.15-1.29], respectively), and patients taking or not taking beta blockers (RR: 1.17 [95% CI 1.06-1.30] and RR: 1.28 [95% CI 1.08-1.51], respectively). Digoxin use was also associated with increased risk of cardiovascular death (RR: 1.32 [95% CI 1.07-1.64]), arrhythmic death (RR: 1.38 [95% CI 1.07-1.79]), and stroke (RR: 1.20 [95% CI 1.004-1.44]). Digoxin treatment is associated with an absolute risk increase of 19 (95% CI 13-26) additional deaths from any cause per 1000 person-years.Digoxin use is associated with a significant increased risk for death from any cause in patients with AF. This finding suggests a need for reconsideration of present treatment recommendations on use of digoxin in AF.

Digoxin Use to Control Ventricular Rate in Patients with Atrial Fibrillation and Heart Failure Is Not Associated with Increased Mortality

Introduction. Digoxin is used to control ventricular rate in atrial fibrillation (AF). There is conflicting evidence regarding safety of digoxin. We aimed to evaluate the risk of mortality with digoxin use in patients with AF using meta-analyses. Methods. PubMed was searched for studies comparing outcomes of patients with AF taking digoxin versus no digoxin, with or without heart failure (HF). Studies were excluded if they reported only a point estimate of mortality, duplicated patient populations, and/or did not report adjusted hazard ratios (HR). The primary endpoint was all-cause mortality. Adjusted HRs were combined using generic inverse variance and log hazard ratios. A multivariate metaregression model was used to explore heterogeneity in studies. Results. Twelve studies with 321,944 patients were included in the meta-analysis. In all AF patients, irrespective of heart failure status, digoxin is associated with increased all-cause mortality (HR [1.23], 95% confidence interval [CI] 1.16-1.31). However, digoxin is not associated with increased mortality in patients with AF and HF (HR [1.08], 95% CI 0.99-1.18). In AF patients without HF digoxin is associated with increased all-cause mortality (HR [1.38], 95% CI 1.12-1.71). Conclusion. In patients with AF and HF, digoxin use is not associated with an increased risk of all-cause mortality when used for rate control.

Increased All-Cause Mortality Associated With Digoxin Therapy in Patients With Atrial Fibrillation: An Updated Meta-Analysis

Digoxin is still commonly used in atrial fibrillation (AF) patients with and without heart failure (HF) for heart rate control. Studies concerning the detrimental effects of digoxin therapy in AF patients are inconsistent. This updated meta-analysis examined the association of digoxin therapy with all-cause mortality in AF patients, stratified by heart function status. We included observational studies with multivariate-adjusted data on digoxin and all-cause mortality in the analysis. The relative risks (RRs) of all-cause mortality were calculated and reported with 95% confidence intervals (95% CIs). Seventeen studies comprising 408,660 patients were included. Overall, in AF patients, digoxin treatment was associated with a significant increase in all-cause mortality after multivariate-adjustment (RR = 1.22; 95% CI 1.15-1.30). When stratified by heart function status, digoxin treatment was associated with a 14% increase in all-cause mortality in AF patients with HF (RR = 1.14, 95% CI 1.04-1.24), and a 36% increase in those without HF (RR = 1.36, 95% CI 1.18-1.56). The increased risk of all-cause mortality was significantly higher in AF patients without HF compared with those with HF (P for interaction = 0.04). This meta-analysis demonstrates that digoxin therapy was associated with a significant increase in all-cause mortality in AF patients, especially in those without HF. Given other available options, digoxin should be avoided as a first-line agent for heart rate control in AF patients.

Digoxin: A systematic review in atrial fibrillation, congestive heart failure and post myocardial infarction

AIM

To review digoxin use in systolic congestive heart failure, atrial fibrillation, and after myocardial infarction.

METHODS

A comprehensive PubMed search was performed using the key words "digoxin and congestive heart failure", "digoxin and atrial fibrillation", "digoxin, atrial fibrillation and systolic congestive heart failure", and "digoxin and myocardial infarction". Only articles written in English were included in this study. We retained studies originating from randomized controlled trials, registries and included at least 500 patients. The studies included patients with atrial fibrillation or heart failure or myocardial infarction and had a significant proportion of patients (at least 5%) on digoxin. A table reviewing the different hazard ratios was developed based on the articles selected. Our primary endpoint was the overall mortality in the patients on digoxin vs those without digoxin, among patients with atrial fibrillation and also among patients with atrial fibrillation and systolic heart failure. We reviewed the most recent international guidelines to discuss current recommendations.

RESULTS

A total of 18 studies were found that evaluated digoxin and overall mortality in different clinical settings including systolic congestive heart failure and normal sinus rhythm (n = 5), atrial fibrillation with and without systolic congestive heart failure (n = 9), and myocardial infarction (n = 4). Overall, patients with systolic congestive heart failure with normal sinus rhythm, digoxin appears to have a neutral effect on mortality especially if close digoxin level monitoring is employed. However, most of the observational studies evaluating digoxin use in atrial fibrillation without systolic congestive heart failure showed an increase in overall mortality when taking digoxin. In the studies evaluated in this systematic review, the data among patients with atrial fibrillation and systolic congestive heart failure, as well as post myocardial infarction were more controversial. The extent to which discrepancies among studies are based on statistical methods is currently unclear, as these studies' findings are generated by retrospective analyses that employed different techniques to address confounding.

CONCLUSION

Based on the potential risks and benefits, as well as the presence of alternative drugs, there is a limited role for digoxin in the management of patients with normal sinus rhythm and congestive heart failure. Based on the retrospective studies reviewed there is a growing volume of data showing increased mortality in those with only atrial fibrillation. The proper role of digoxin is, however, less certain in other subgroups of patients, such as those with both atrial fibrillation and systolic congestive heart failure or after a myocardial infarction. Further studies may provide helpful information for such subgroups of patients.

Digoxin Use and Subsequent Outcomes Among Patients in a Contemporary Atrial Fibrillation Cohort

BACKGROUND

Although digoxin has long been used to treat atrial fibrillation (AF) and heart failure (HF), its safety remains controversial.

OBJECTIVES

This study sought to describe digoxin use over time in patients with AF who were stratified by the presence or absence of HF, to characterize the predictors of digoxin use and initiation, and to correlate digoxin use with outcomes.

METHODS

Longitudinal patterns of digoxin use and its association with a variety of outcomes were assessed in a prospective outpatient registry conducted at 174 U.S. sites with enrollment from June 2010 to August 2011.

RESULTS

Among 9,619 patients with AF and serial follow-up every 6 months for up to 3 years, 2,267 (23.6%) received digoxin at study enrollment, 681 (7.1%) were initiated on digoxin during follow-up, and 6,671 (69.4%) were never prescribed digoxin. After adjusting for other medications, heart rate was 72.9 beats/min among digoxin users and 71.5 beats/min among nonusers (p < 0.0001). Prevalent digoxin use at registry enrollment was not associated with subsequent onset of symptoms, hospitalization, or mortality (in patients with HF, adjusted hazard ratio [HR] for death: 1.04; without HF, HR: 1.22). Incident digoxin use during follow-up was not associated with subsequent death in patients with HF (propensity adjusted HR: 1.05), but was associated with subsequent death in those without HF (propensity adjusted HR: 1.99).

CONCLUSIONS

After adjustment for detailed clinical factors, digoxin use in registry patients with AF had a neutral association with outcomes under most circumstances. Because of the multiple conflicting observational reports about digoxin's safety and possible concerns in specific clinical situations, a large pragmatic trial of digoxin therapy in AF is needed.

Impact of Digoxin on Mortality in Patients With Atrial Fibrillation Stratified by Heart Failure: Findings From Gulf Survey of Atrial Fibrillation Events in the Middle East

OBJECTIVE

The use of digoxin in patients having atrial fibrillation (AF) with or without heart failure (HF) is not without controversy. The aim of this study was to examine the impact of digoxin therapy on mortality stratified by HF.

METHODS

Gulf Survey of Atrial Fibrillation Events was a prospective, multinational, observational registry of consecutive patients with AF recruited from the emergency department of 23 hospitals in 6 countries in the Middle East. Patients were recruited between October 2009 and June 2010 and followed up for 1 year after enrollment. Analyses were performed using univariate and multivariate statistical techniques.

RESULTS

The study included a total of 1962 patients with AF, with an overall mean age of 56 ± 16 years, and 52% (n = 1026) were males. At hospital discharge, digoxin was prescribed in 36% (n = 709) of the patients, whereas HF was present in 27% (n = 528) of the cohort. A total of 225 (12.1%) patients died during the 12-month follow-up period after discharge (5.3% [n = 104] were lost to follow-up). Patients with HF were consistently associated with higher mortality at 1 month (5.1% vs 2.1%; P < .001), 6 months (17.2% vs 5.0%; P < 0.001), and 12 months (24.3% vs 7.6%; P < .001) when compared to those without HF. When stratified by HF, digoxin therapy was associated with significantly higher mortality in those without HF at 6 months (8.7% vs 3.7%; adjusted odds ratio (aOR), 5.07; P < .001) and 12 months (12.3% vs 6.0%; aOR, 4.22; P < .001) but not in those with HF (6 months: 18.6% vs 14.7%; aOR, 1.62; P = .177 and 12 months: 25.4% vs 22.4%; aOR, 1.37; P = .317).

CONCLUSIONS

In patients with AF and HF, digoxin did not offer any survival advantages. However, in those without HF, digoxin therapy was, in fact, associated with significantly higher long-term mortality.

Safety and efficacy of digoxin: systematic review and meta-analysis of observational and controlled trial data

OBJECTIVE

To clarify the impact of digoxin on death and clinical outcomes across all observational and randomised controlled trials, accounting for study designs and methods.

DATA SOURCES AND STUDY SELECTION

Comprehensive literature search of Medline, Embase, the Cochrane Library, reference lists, and ongoing studies according to a prospectively registered design (

PROSPERO

CRD42014010783), including all studies published from 1960 to July 2014 that examined treatment with digoxin compared with control (placebo or no treatment).

DATA EXTRACTION AND SYNTHESIS

Unadjusted and adjusted data pooled according to study design, analysis method, and risk of bias.

MAIN OUTCOME MEASURES

Primary outcome (all cause mortality) and secondary outcomes (including admission to hospital) were meta-analysed with random effects modelling.

RESULTS

52 studies were systematically reviewed, comprising 621,845 patients. Digoxin users were 2.4 years older than control (weighted difference 95% confidence interval 1.3 to 3.6), with lower ejection fraction (33% v 42%), more diabetes, and greater use of diuretics and anti-arrhythmic drugs. Meta-analysis included 75 study analyses, with a combined total of 4,006,210 patient years of follow-up. Compared with control, the pooled risk ratio for death with digoxin was 1.76 in unadjusted analyses (1.57 to 1.97), 1.61 in adjusted analyses (1.31 to 1.97), 1.18 in propensity matched studies (1.09 to 1.26), and 0.99 in randomised controlled trials (0.93 to 1.05). Meta-regression confirmed that baseline differences between treatment groups had a significant impact on mortality associated with digoxin, including markers of heart failure severity such as use of diuretics (P=0.004). Studies with better methods and lower risk of bias were more likely to report a neutral association of digoxin with mortality (P<0.001). Across all study types, digoxin led to a small but significant reduction in all cause hospital admission (risk ratio 0.92, 0.89 to 0.95; P<0.001; n=29,525).

CONCLUSIONS

Digoxin is associated with a neutral effect on mortality in randomised trials and a lower rate of admissions to hospital across all study types. Regardless of statistical analysis, prescription biases limit the value of observational data.

Digoxin-associated mortality: a systematic review and meta-analysis of the literature

There are conflicting data regarding the effect of digoxin use on mortality in patients with atrial fibrillation (AF) or with congestive heart failure (CHF). The aim of this meta-analysis was to provide detailed analysis of the currently available study reports. We performed a MEDLINE and a COCHRANE search (1993-2014) of the English literature dealing with the effects of digoxin on all-cause-mortality in subjects with AF or CHF. Only full-sized articles published in peer-reviewed journals were considered for this meta-analysis. A total of 19 reports were identified. Nine reports dealt with AF patients, seven with patients suffering from CHF, and three with both clinical conditions. Based on the analysis of adjusted mortality results of all 19 studies comprising 326 426 patients, digoxin use was associated with an increased relative risk of all-cause mortality [Hazard ratio (HR) 1.21, 95% confidence interval (CI), 1.07 to 1.38, P < 0.01]. Compared with subjects not receiving glycosides, digoxin was associated with a 29% increased mortality risk (HR 1.29; 95% CI, 1.21 to 1.39) in the subgroup of publications comprising 235 047 AF patients. Among 91.379 heart failure patients, digoxin-associated mortality risk increased by 14% (HR 1.14, 95% CI, 1.06 to 1.22). The present systematic review and meta-analysis of all available data sources suggest that digoxin use is associated with an increased mortality risk, particularly among patients suffering from AF.

Meta-analysis of digoxin use and risk of mortality in patients with atrial fibrillation

There is an ongoing debate on the safety of digoxin use in patients with atrial fibrillation (AF). To address this issue, the investigators assembled a synthesis of the available evidence on the relation between digoxin and all-cause mortality in patients with AF. PubMed and the Embase database were systematically searched to identify all eligible studies examining the association between digoxin use and the mortality risk in AF. Overall hazard ratios and 95% confidence intervals were calculated using the random-effects model. Eleven observational studies were identified that met the inclusion criteria, 5 of which additionally used propensity score matching for statistical adjustment. In total, 318,191 patients were followed up for a mean of 2.8 years. Overall, digoxin use was associated with a 21% increased risk for mortality (hazard ratio 1.21, 95% confidence interval 1.12 to 1.30). Sensitivity analyses found the results to be robust. In the propensity score-matched AF patients, digoxin use was associated with a 17% greater risk for mortality (hazard ratio 1.17, 95% confidence interval 1.13 to 1.22). When the AF cohort was grouped into patients with and without heart failure, the use of digoxin was associated with an increase in mortality in patients with and those without heart failure, and no significant heterogeneity was seen between the groups (p >0.10). In conclusion, the results suggest that digoxin use was associated with a greater risk for mortality in patients with AF, regardless of concomitant heart failure. A well-powered randomized trial is necessary to reveal the true effect of digoxin.

Digoxin treatment is associated with increased total and cardiovascular mortality in anticoagulated patients with atrial fibrillation

BACKGROUND

Some evidences suggest that the use of digoxin may be harmful inatrial fibrillation (AF) patients. The aim of the study was to investigate in a "real world" of AF patients receiving vitamin K antagonists (VKAs), the relationship between digoxin use and mortality.

METHODS

Prospective single-center observational study including 815 consecutive non-valvular AF patients treated with VKAs. Total mortality was the primary outcome of the study. We also performed a sub-analysis considering only cardiovascular (CV) deaths. Time in therapeutic range (TTR) was used for anticoagulation quality.

RESULTS

Median follow-up was 33.2months (2460 person-years); 171 (21.0%) patients were taking digoxin. Compared to those without, patients on digoxin were older (p=0.007), with a clinical history of HF (p<0.001) and at higher risk of thromboembolic events (p<0.001). No difference in TTR between the two groups was registered (p=0.598). During the follow-up, 85 deaths occurred: 47 CV and 38 non-CV deaths; 35 deaths occurred in digoxin users (20.6%). A significant increased rate of total mortality was observed in digoxin-treated patients (p<0.001). Multivariable analysis showed that digoxin was associated with total mortality (hazard ratio [HR]: 2.224, p<0.001) and CV death (HR: 4.686, p<0.001). A propensity score-matched analysis confirmed that digoxin was associated with total mortality (HR: 2.073, p=0.0263) and CV death (HR: 4.043, p=0.004).

CONCLUSIONS

In AF patients on good anticoagulation control with VKAs, digoxin use was associated with a higher rate of total and CV mortality.

Interaction between digoxin and dronedarone in the PALLAS trial

BACKGROUND

Elevated serum digoxin concentration can cause toxicity, including death. Dronedarone increases digoxin concentration by P-glycoprotein interaction. In Permanent Atrial Fibrillation Outcome Study Using Dronedarone On Top Of Standard Therapy Trial (PALLAS), dronedarone was associated with both increased cardiovascular death and heart failure in patients with permanent atrial fibrillation. The present analysis examines whether the dronedarone-digoxin interaction might explain these adverse outcomes.

METHODS AND RESULTS

Subgroup analysis was performed to compare outcomes of patients on digoxin at baseline or not. In PALLAS, 1619 patients were randomized to dronedarone and 1617 to placebo, of whom 544 (33.6%) and 526 (32.5%) were receiving digoxin, respectively. Median (Q1,Q3) digoxin serum concentration on day 7 was 1.1 (0.7,1.5) ng/mL on dronedarone and 0.7 (0.5,1.1) ng/mL on placebo (P<0.001). Among patients on digoxin, there were 15 (8.6%/year) cardiovascular deaths on dronedarone and 2 (1.2%/year) on placebo (adjusted hazard ratio, 7.31; 95% confidence interval, 1.66-32.20; P=0.009). Among patients not on digoxin, there were 6 cardiovascular deaths on dronedarone (1.7%/year) and 8 on placebo (2.2%/year; adjusted hazard ratio, 0.67; 95% confidence interval, 0.23-1.95; P=0.46; interaction P value 0.01). In patients on digoxin, there were 11 arrhythmic deaths on dronedarone and none on placebo; and in patients not on digoxin, there were 2 arrhythmic deaths on dronedarone and 4 on placebo (P value for interaction 0.002). There was no interaction between baseline digoxin use and the adverse effect of dronedarone on heart failure events.

CONCLUSIONS

In PALLAS, there was a strong effect of concurrent digoxin use on the adverse effect of dronedarone on cardiovascular death, but not on occurrence of heart failure.

CLINICAL TRIAL REGISTRATION

http://www.clinicaltrials.gov. Unique identifier: NCT01151137.

Synthesis and biological evaluation of liguzinediol mono- and dual ester prodrugs as promising inotropic agents

The potent positive inotropic effect, together with the relatively low safety risk of liguzinediol (LZDO), relative to currently available inotropic drugs, has prompted us to intensively research and develop LZDO as a potent positive inotropic agent. In this study, to obtain LZDO alternatives for oral chronic administration, a series of long-chain fatty carboxylic mono- and dual-esters of LZDO were synthesized, and preliminarily evaluated for physicochemical properties and bioconversion. Enhanced lipophilic properties and decreased solubility of the prodrugs were observed as the side chain length increased. All esters showed conspicuous chemical stability in phosphate buffer (pH 7.4). Moreover, the enzymatic hydrolysis of esters in human plasma and human liver microsomes confirmed that the majority of esters were converted to LZDO, with release profiles that varied due to the size and structure of the side chain. In vivo pharmacokinetic studies following oral administration of monopivaloyl (M5), monodecyl (M10) and monododecyl (M12) esters demonstrated the evidently extended half-lives relative to LZDO dosed alone. In particular the monopivaloyl ester M5 exhibited an optimal pharmacokinetic profile with appropriate physiochemical characteristics.

Increased mortality associated with digoxin in contemporary patients with atrial fibrillation: findings from the TREAT-AF study

BACKGROUND

Despite endorsement of digoxin in clinical practice guidelines, there exist limited data on its safety in atrial fibrillation/flutter (AF).

OBJECTIVES

The goal of this study was to evaluate the association of digoxin with mortality in AF.

METHODS

Using complete data of the TREAT-AF (The Retrospective Evaluation and Assessment of Therapies in AF) study from the U.S. Department of Veterans Affairs (VA) healthcare system, we identified patients with newly diagnosed, nonvalvular AF seen within 90 days in an outpatient setting between VA fiscal years 2004 and 2008. We used multivariate and propensity-matched Cox proportional hazards to evaluate the association of digoxin use with death. Residual confounding was assessed by sensitivity analysis.

RESULTS

Of 122,465 patients with 353,168 person-years of follow-up (age 72.1 ± 10.3 years, 98.4% male), 28,679 (23.4%) patients received digoxin. Cumulative mortality rates were higher for digoxin-treated patients than for untreated patients (95 vs. 67 per 1,000 person-years; p < 0.001). Digoxin use was independently associated with mortality after multivariate adjustment (hazard ratio [HR]: 1.26, 95% confidence interval [CI]: 1.23 to 1.29, p < 0.001) and propensity matching (HR: 1.21, 95% CI: 1.17 to 1.25, p < 0.001), even after adjustment for drug adherence. The risk of death was not modified by age, sex, heart failure, kidney function, or concomitant use of beta-blockers, amiodarone, or warfarin.

CONCLUSIONS

Digoxin was associated with increased risk of death in patients with newly diagnosed AF, independent of drug adherence, kidney function, cardiovascular comorbidities, and concomitant therapies. These findings challenge current cardiovascular society recommendations on use of digoxin in AF.

Relation of digoxin use in atrial fibrillation and the risk of all-cause mortality in patients ≥65 years of age with versus without heart failure

Previous studies on digoxin use in patients with atrial fibrillation (AF) and the risk of all-cause mortality found conflicting results. We conducted a population-based, retrospective, cohort study of patients aged ≥65 years admitted to a hospital with a primary or secondary diagnosis of AF, in Quebec province, Canada, from 1998 to 2012. The AF cohort was grouped into patients with and without heart failure (HF) and into digoxin and no-digoxin users according to the first prescription filled for digoxin within 30 days after AF hospital discharge. We derived propensity score-matched digoxin and no-digoxin treatment groups for the groups of patients with and without HF, respectively, and conducted multivariable Cox proportional hazards regression analyses to determine association between digoxin use and all-cause mortality. The AF propensity score-matched cohorts of patients with and without HF were well balanced on baseline characteristics. In the propensity score-matched HF group, digoxin use was associated with a 14% greater risk of all-cause mortality (adjusted hazard ratio 1.14, 95% confidence interval 1.10 to 1.17). In the propensity score-matched no-HF group, digoxin use was associated with a 17% greater risk of all-cause mortality (adjusted hazard ratio 1.17, 95% confidence interval 1.14 to 1.19). In conclusion, our retrospective analyses found that digoxin use was associated with a greater risk for all-cause mortality in patients aged ≥65 years with AF regardless of concomitant HF. Large, multicenter, randomized controlled trials or prospective cohort studies are required to clarify this issue.

Digoxin in patients with permanent atrial fibrillation: data from the RACE II study

BACKGROUND

The Atrial Fibrillation Follow-up Investigation of Rhythm Management trial showed that digoxin was associated with increased mortality in patients with atrial fibrillation.

OBJECTIVES

To assess the association of digoxin with cardiovascular (CV) morbidity and mortality in patients with permanent atrial fibrillation enrolled in the Dutch Rate Control Efficacy in Permanent AF: A Comparison Between Lenient Versus Strict Rate Control II trial as well as to assess the role of digoxin to achieve heart rate targets.

METHODS

The primary outcome was a composite of CV morbidity and mortality. Secondary outcomes included CV hospitalization and all-cause mortality or heart failure (HF) hospitalization. Of the 614 patients, 608 (99%) completed the dose-adjustment phase. Outcome events were analyzed from the end of the dose-adjustment phase until the end of follow-up. The median follow-up period was 2.9 years (interquartile range 2.7-3.0 years).

RESULTS

In total, 284 patients (46.7%) used digoxin after the dose-adjustment phase (median dosage 0.250 mg; interquartile range 0.0625-0.750 mg). These patients were more often women, previously admitted for HF, had an increased left ventricular end-systolic diameter, and more often randomized to strict rate control. By using Cox proportional hazards regression analysis, the use of digoxin was not associated with an increased risk for the primary and secondary outcomes. For the primary outcome, the 3-year estimated cumulative incidence was 12.9% vs 13.4% in the digoxin group vs the no-digoxin group (unadjusted hazard ratio [HR] 0.97; 95% confidence interval [CI] 0.62-1.52). Incidence was 19.4% vs. 19.5% for CV hospitalization (unadjusted HR 1.00; 95% CI 0.69-1.45) and 6.6% vs. 9.9% for all-cause mortality or HF hospitalization (unadjusted HR 0.62; 95% CI 0.34-1.13) in the digoxin group vs the no-digoxin group.

CONCLUSION

The use of digoxin was not associated with increased morbidity and mortality.

The novel compound liguzinediol exerts positive inotropic effects in isolated rat heart via sarcoplasmic reticulum Ca2+ ATPase-dependent mechanism

AIMS

The present work investigated the underlying mechanism for the positive inotropic effect of liguzinediol (LZDO) in isolated rat hearts.

MAIN METHODS

Isolated rat heart perfusion, intracellular action potential recording, patch clamp and Ca2+ imaging were used to measure the isolated rat heart contractility, action potential duration, L-type Ca2+ current and sarcoplasmic reticulum (SR) Ca2+ transient in rat cardiomyocyte, respectively.

KEY FINDINGS

LZDO (1, 10, and 100μM) significantly enhanced the inotropy of isolated rat hearts, but not heart rates. Nimodipine (1μM, an L-type Ca2+ channel antagonist), ruthenium red (5μM, a ryanodine receptor inhibitor) and thapsigargin (2μM, an irreversible SR Ca2+ ATPase inhibitor) completely blocked the positive inotropic effect of LZDO. LZDO significantly enhanced the intracellular Ca2+ transient in rat cardiomyocyte. However, LZDO (100μM) did not increase L-type Ca2+ channel current. Moreover, LZDO (100μM) restored the depletion effect of caffeine on Ca2+ transient. The following compounds also failed to block the positive inotropic effect of LZDO (100μM): β-AR antagonist (propranolol 1μM), phosphodiesterase (PDE) inhibitor (IBMX 5μM), Na+-K+ ATPase inhibitor (ouabain 1μM), α(1)-AR antagonist (prazosin 1μM), dopamine D1 receptor antagonist (SCH23390 1μM) and Na+-Ca2+ exchange inhibitor (KB-R7943 1μM).

SIGNIFICANCE

The positive inotropic effect of LZDO in isolated rat hearts was mediated through an elevation of SR Ca2+ transient, which may act on SR Ca2+ ATPase. LZDO has a unique biological mechanism that may prove effective in treating heart failure in clinic.

Digoxin - time to take the gloves off?

Digoxin has been used for hundreds of years to aid rate control in atrial fibrillation and as a positive inotrope in heart failure. Our familiarity with digoxin has allowed it to become easily prescribed even though there are data suggesting that use of digoxin may in fact result in increased mortality and pro-arrhythmia. Within this review we explain some of the outcome data associated with digoxin use to determine if it is time to take the gloves off and examine if we should still be using this drug in the 21st century.

Atrial fibrillation in heart failure: current treatment of patients with remodeled atria

Atrial fibrillation (AF) and chronic heart failure (CHF) can be caused by each other, and therefore constitute a vicious circle. The prevalence of both conditions is about 1% in industrialized countries and increases with age. Although mortality is increased in heart failure, the additional prognostic relevance of AF in these patients is less clear. AF in patients with CHF can worsen heart failure symptoms, cause complications (eg, stroke), and is difficult to treat. Thus, prevention of AF entirely is an important goal. This review summarizes recent data concerning prognostic relevance, treatment, and means of primary and secondary prevention of AF in patients with CHF.

Novel therapeutic applications of cardiac glycosides

Cardiac glycosides are a diverse family of naturally derived compounds that bind to and inhibit Na+/K+-ATPase. Members of this family have been in clinical use for many years for the treatment of heart failure and atrial arrhythmia, and the mechanism of their positive inotropic effect is well characterized. Exciting recent findings have suggested additional signalling modes of action of Na+/K+-ATPase, implicating cardiac glycosides in the regulation of several important cellular processes and highlighting potential new therapeutic roles for these compounds in various diseases. Perhaps most notably, the increased susceptibility of cancer cells to these compounds supports their potential use as cancer therapies, and the first generation of glycoside-based anticancer drugs are currently in clinical trials.