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

Review: Failure of current digoxin monitoring for toxicity: new monitoring recommendations to maintain therapeutic levels for efficacy

The current recommendations for monitoring digoxin, a narrow therapeutic index drug, are limited to confirming medication use or investigating suspicion of toxicity and fail our oath to do no harm. Numerous meta-analyses evaluating digoxin use consistently recommend frequent monitoring to maintain the level of 0.5 to ≤1.0 ng/ml because higher levels lead to increased morbidity and mortality without benefit. Data from the United States National Poison Control Center (2012-2020) show annual deaths due to digoxin of 18-36 compared to lithium's 1-7, and warfarin's 0-2 respectively. The latter drugs also have narrow therapeutic indexes like digoxin yet are more carefully monitored. Recognition of digoxin toxicity is impaired as levels are not being routinely checked after medications are added to a patient's regimen. In addition, providers may be using ranges to guide treatment that are no longer appropriate. It is imperative that monitoring guidelines and laboratory therapeutic levels are revised to reduce morbidity and mortality due to digoxin. In this review, we provide a comprehensive literature review of digoxin monitoring guidelines, digoxin toxicity, and evidence to support revising the ranges for serum digoxin monitoring.

Effect of digoxin on all-cause and cardiovascular mortality in patients with atrial fibrillation with and without heart failure: an umbrella review of systematic reviews and 12 meta-analyses

PURPOSE

To perform a systematic umbrella review with meta-analysis to evaluate the certainty of evidence on mortality risk associated with digoxin use in patients with atrial fibrillation (AF) with or without heart failure (HF).

METHODS

We systematically searched MEDLINE, Embase, and Web of Science databases from inception to 19 October 2021. We included systematic reviews and meta-analyses of observational studies investigating digoxin effects on mortality of adult patients with AF and/or HF. The primary outcome was all-cause mortality; secondary outcome was cardiovascular mortality. Certainty of evidence was evaluated by the Grading of Recommendations Assessment, Development and Evaluation (GRADE) tool and the quality of systematic reviews/meta-analyses by the A MeaSurement Tool to Assess systematic Reviews 2 (AMSTAR2) tool.

RESULTS

Eleven studies accounting for 12 meta-analyses were included with a total of 4,586,515 patients. AMSTAR2 analysis showed a high quality in 1, moderate in 5, low in 2, and critically low in 3 studies. Digoxin was associated with an increased all-cause mortality (hazard ratio [HR] 1.19, 95% confidence interval [95%CI] 1.14-1.25) with moderate certainty of evidence and with an increased cardiovascular mortality (HR 1.19, 95%CI 1.06-1.33) with moderate certainty of evidence. Subgroup analysis showed that digoxin was associated with all-cause mortality both in patients with AF alone (HR 1.23, 95%CI 1.19-1.28) and in those with AF and HF (HR 1.14, 95%CI 1.12-1.16).

CONCLUSION

Data from this umbrella review suggests that digoxin use is associated with a moderate increased risk of all-cause and cardiovascular mortality in AF patients regardless of the presence of HF.

TRIAL REGISTRATION

This review was registered in PROSPERO (CRD42022325321).

Rate control strategies for atrial fibrillation

Atrial fibrillation (AF) is one of the main cardiac arrhythmias associated with higher risk of cardiovascular morbidity and mortality. AF can cause adverse symptoms and reduced quality of life. One of the strategies for the management of AF is rate control, which can modulate ventricle rate, alleviate adverse associated symptoms and improve the quality of life. As primary management of AF through rate control or rhythm is a topic under debate, the purpose of this review is to explore the rationale for the rate control approach in managing AF by considering the guidelines, recommendations and determinants for the choice of rate control drugs, including beta blockers, digoxin and non- dihydropyridine calcium channel blockers for patients with AF and other comorbidities and atrioventricular nodal ablation and pacing. Despite the limitations of rate control treatment, which may not be effective in preventing disease progression or in reducing symptoms in highly symptomatic patients, it is widely used for almost all patients with atrial fibrillation. Although rate control is one of the first line management of all patient with atrial fibrillation, several issues remain debateable.

Safety of digoxin in nonagenarian patients with atrial fibrillation: lessons from the Spanish Multicenter Registry

BACKGROUND

The association between digoxin and mortality is an unclear issue. In older patients with atrial fibrillation (AF), where use of digoxin is frequent, the evidence of its safety is scarce. Our aim is to assess the safety of digoxin in nonagenarian patients with AF.

METHODS

We evaluated data from 795 nonagenarian patients with non-valvular AF from the Spanish Multicenter Registry. We analyzed the relationship between digoxin and all-cause mortality with the Cox proportional-hazards model.

RESULTS

Follow-up was 27.7 ± 18.3 months. Mean age was 92.5 ± 3.8 years, and 71% of nonagenarian patients were female. Digoxin was not associated with increased risk of mortality [adjusted hazard ratio (aHR) = 1.16, 95% CI: 0.96−1.41,P = 0.130]. However, we found a significant increase in mortality in the subgroup with estimated glomerular filtration rate (eGFR) < 30 mL/min per 1.73 m ² (aHR = 2.01, 95% CI: 1.13−3.57,P = 0.018), but not in the other subgroups of eGFR (30−59 mL/min per 1.73 m² and ≥ 60 mL/min per 1.73 m²). When exploring the risk of mortality according to sex, male subgroup was associated with an increase in mortality (aHR = 1.48, 95% CI: 1.02−2.14,P = 0.041). This was not observed in females subgroup (aHR = 1.03, 95% CI: 0.81−1.29,P = 0.829). Based on the presence or absence of heart failure, we did not find significant differences (aHR = 1.20, 95% CI: 0.87−1.65,P = 0.268 vs. aHR = 1.15, 95% CI: 0.90−1.47,P = 0.273, respectively).

CONCLUSIONS

In our large registry of nonagenarian patients with AF, we did not find an association between digoxin and mortality in the total sample. However, in the subgroup analyses, we found an increase in mortality with the use of digoxin in men and in patients with an eGFR < 30 mL/min per 1.73 m ².

AV junction ablation and cardiac resynchronization for patients with permanent atrial fibrillation and narrow QRS: the APAF-CRT mortality trial

AIMS 

In patients with atrial fibrillation (AF) and heart failure (HF), strict and regular rate control with atrioventricular junction ablation and biventricular pacemaker (Ablation + CRT) has been shown to be superior to pharmacological rate control in reducing HF hospitalizations. However, whether it also improves survival is unknown.

METHODS AND RESULTS 

In this international, open-label, blinded outcome trial, we randomly assigned patients with severely symptomatic permanent AF >6 months, narrow QRS (≤110 ms) and at least one HF hospitalization in the previous year to Ablation + CRT or to pharmacological rate control. We hypothesized that Ablation + CRT is superior in reducing the primary endpoint of all-cause mortality. A total of 133 patients were randomized. The mean age was 73 ± 10 years, and 62 (47%) were females. The trial was stopped for efficacy at interim analysis after a median of 29 months of follow-up per patient. The primary endpoint occurred in 7 patients (11%) in the Ablation + CRT arm and in 20 patients (29%) in the Drug arm [hazard ratio (HR) 0.26, 95% confidence interval (CI) 0.10-0.65; P = 0.004]. The estimated death rates at 2 years were 5% and 21%, respectively; at 4 years, 14% and 41%. The benefit of Ablation + CRT of all-cause mortality was similar in patients with ejection fraction (EF) ≤35% and in those with >35%. The secondary endpoint combining all-cause mortality or HF hospitalization was significantly lower in the Ablation + CRT arm [18 (29%) vs. 36 (51%); HR 0.40, 95% CI 0.22-0.73; P = 0.002].

CONCLUSIONS 

Ablation + CRT was superior to pharmacological therapy in reducing mortality in patients with permanent AF and narrow QRS who were hospitalized for HF, irrespective of their baseline EF.

STUDY REGISTRATION

ClinicalTrials.gov Identifier: NCT02137187.

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.

Atrial fibrillation in acute heart failure: A position statement from the Acute Cardiovascular Care Association and European Heart Rhythm Association of the European Society of Cardiology

Atrial fibrillation and acute heart failure frequently co-exist and can exacerbate each other. Their combination leads to increased morbidity and mortality. However, the prevalence and significance, as well as the treatment, of atrial fibrillation in acute heart failure are not well studied. Management of atrial fibrillation in acute heart failure requires a multidisciplinary team approach. Treatment of underlying disease(s), identification and treatment of potentially correctable causes and precipitating factors and anticoagulation are crucial. In this article, current evidence on atrial fibrillation in the setting of acute heart failure is summarised. The recommendations on management of atrial fibrillation in the prehospital stage, the treatment of reversible causes, when and how to use rate or rhythm control, maintenance of sinus rhythm, catheter ablation and pacing, anticoagulation, as well as measures on prevention of atrial fibrillation are provided.

Outcomes of cardiac resynchronisation therapy in patients with heart failure with atrial fibrillation: a systematic review and meta-analysis of observational studies

Background

Cardiac resynchronisation therapy (CRT) is beneficial in selected patients with heart failure (HF) in normal sinus rhythm (NSR). We sought to evaluate the impact of CRT with or without atrioventricular junction (AVJ) ablation in patients with HF with concomitant atrial fibrillation (AF).

Methods and results

Literature was searched (inception through 30 August 2017) for observational studies that reported outcomes in patients with HF with CRT and AF that reported all-cause and cardiovascular mortality. Thirty-one studies with 83, 571 patients were included. CRT did not decrease mortality compared with internal cardioverter defibrillator or medical therapy alone in patients with HF and AF with indications for CRT (OR: 0.851, 95% CI 0.616 to 1.176, p=0.328, I2=86.954). CRT-AF patients had significantly higher all-cause and cardiovascular mortality than CRT-NSR patients ([OR: 1.472, 95% CI 1.301 to 1.664, p=0.000] and [OR: 1.857, 95% CI 1.350 to 2.554, p=0.000] respectively). Change in left ventricular ejection fraction was not different between CRT patients with and without AF (p=0.705). AVJ ablation, however, improved all-cause mortality in CRT-AF patients when compared with CRT-AF patients without AVJ ablation (OR: 0.485, 95% CI 0.247 to 0.952, p=0.035). With AVJ ablation, there was no difference in all-cause mortality in CRT-AF patients compared with CRT-NSR patients (OR: 1.245, 95% CI 0.914 to 1.696, p=0.165).

Conclusion

The results of our meta-analysis suggest that AF was associated with decreased CRT benefits in patients with HF. CRT, however, benefits patients with AF with AVJ ablation.

Augmentation of Ouabain-Induced Increase in Heart Muscle Contractility by Akt Inhibitor MK-2206

Cardiac steroids (CSs), such as ouabain and digoxin, increase the force of contraction of heart muscle and are used for the treatment of congestive heart failure (CHF). However, their small therapeutic window limits their use. It is well established that Na+, K+-ATPase inhibition mediates CS-induced increase in heart contractility. Recently, the involvement of intracellular signal transduction was implicated in this effect. The aim of the present study was to test the hypothesis that combined treatment with ouabain and Akt inhibitor (MK-2206) augments ouabain-induced inotropy in mammalian models. We demonstrate that the combined treatment led to an ouabain-induced increase in contractility at concentrations at which ouabain alone was ineffective. This was shown in 3 experimental systems: neonatal primary rat cardiomyocytes, a Langendorff preparation, and an in vivo myocardial infarction induced by left anterior descending coronary artery (LAD) ligation. Furthermore, cell viability experiments revealed that this treatment protected primary cardiomyocytes from MK-2206 toxicity and in vivo reduced the size of scar tissue 10 days post-LAD ligation. We propose that Akt activity imposes a constant inhibitory force on muscle contraction, which is attenuated by low concentrations of MK-2206, resulting in potentiation of the ouabain effect. This demonstration of the increase in the CS effect advocates the development of the combined treatment in CHF.

Real-life use of digoxin in patients with non-valvular atrial fibrillation: data from the RAMSES study

WHAT IS KNOWN AND OBJECTIVE

Although inappropriate use of digoxin has been described in various populations, a real-world evaluation of patterns of digoxin prescription has not been well studied in patients with atrial fibrillation (AF). The aim of this study was to identify prevalence, indications and appropriateness of digoxin use in the general population of patients with non-valvular AF (NVAF) in Turkey.

METHODS

We included and classified patients from the RAMSES (ReAl-life Multicentre Survey Evaluating Stroke prevention strategies in Turkey) study, a prospective registry including 6273 patients with NVAF, on the basis of digoxin use. After excluding the data of 73 patients whose medical history about digoxin use or left ventricle function was absent, 6200 patients were included for the final analysis. Digoxin use was considered inappropriate if patients did not have left ventricular systolic dysfunction or symptomatic heart failure (HF).

RESULTS AND DISCUSSION

Digoxin was used in 1274 (20·5%) patients. Patients treated with digoxin were older (71·4 ± 9·8 years vs. 69·2 ± 10·9 years, P < 0·001), more likely to be female (58·8% vs. 55·9%, P = 0·019) and had more common comorbidities such as HF (40·2% vs. 17·4%), diabetes (26·4% vs. 21·1%), coronary artery disease (35·3 vs. 27·6%) and persistent/permanent AF (93·4% vs. 78·4%; P < 0·001 for each comparison). Of the 1274 patients, the indication of digoxin use was considered inappropriate in 762 (59·8%).

WHAT IS NEW AND CONCLUSION

Our findings show that nearly one-fifth of the patients with NVAF were on digoxin therapy and nearly 60% of these patients were receiving digoxin with inappropriate indications in a real-world setting.

Rate control in atrial fibrillation

Control of the heart rate (rate control) is central to atrial fibrillation management, even for patients who ultimately require control of the rhythm. We review heart rate control in patients with atrial fibrillation, including the rationale for the intervention, patient selection, and the treatments available. The choice of rate control depends on the symptoms and clinical characteristics of the patient, but for all patients with atrial fibrillation, rate control is part of the management. Choice of drugs is patient-dependent. β blockers, alone or in combination with digoxin, or non-dihydropyridine calcium-channel blockers (not in heart failure) effectively lower the heart rate. Digoxin is least effective, but a reasonable choice for physically inactive patients aged 80 years or older, in whom other treatments are ineffective or are contraindicated, and as an additional drug to other rate-controlling drugs, especially in heart failure when instituted cautiously. Atrioventricular node ablation with pacemaker insertion for rate control should be used as an approach of last resort but is also an option early in the management of patients with atrial fibrillation treated with cardiac resynchronisation therapy. However, catheter ablation of atrial fibrillation should be considered before atrioventricular node ablation. Although rate control is a top priority and one of the first management issues for all patients with atrial fibrillation, many issues remain.

Correlation between impedance cardiography and 6 min walk distance in atrial fibrillation patients

Background

The correlation between impedance cardiography (ICG) and 6 min walk distance (6MWD) in atrial fibrillation (AF) patients remains unknown.

Methods

We recruited 49 subjects in the study (21 AF patients and 28 patients without AF) and estimated hemodynamic parameters: cardiac output (CO), stroke volume (SV), stroke volume index (SVI), left stroke work (LSW), left stroke work index (LSWI), stroke systemic vascular resistance (SSVR), stroke systemic vascular resistance index (SSVRI); 6MWD, left ventricle ejection fraction (LVEF), NT-pro brain natriuretic peptide (NT-pro BNP) for the two groups.

Results

The AF group have apparently lower CO (2.26 ± 0.14 VS 4.11 ± 0.20 L/min, p = 0.039) and distinctly higher SVR (677.60 ± 69.10 VS 344.41 ± 22.98 dynes/cm⁵, p = 0.001), SSVRI (396.97 ± 36.80 VS 199.01 ± 11.72 dynes/cm⁵/m², p < 0.001) than the control group. NT-pro BNP (1409.48 ± 239.90 VS 332.59 ± 68.85 pg/ml, p = 0.001) in the AF group was significantly higher than the control group and 6MWD (264.33 ± 14.55 VS 428.79 ± 29.98 m, p < 0.001) in the AF group was lower than the control group. There was no significant difference in LVEF between the two groups (62.67 ± 7.62 % VS 63.93 ± 5.03 %, p = 0.470). Pearson correlation analysis revealed that CO (R = 0.494, p = 0.023), SV (R = 0.633, p = 0.002), LSW (R = 0.615, p = 0.003) and LSWI (R = 0.491, p = 0.024) significantly correlated positively with 6MWD in AF patients.

Conclusions

AF patients had lower cardiac output, shorter 6MWD and higher NT-pro BNP than patients with sinus rhythm. The cardiac output measured by impedance cardiography significantly correlated positively with 6MWD in AF patients.