Increased mortality after dronedarone therapy for severe heart failure

Saudi Heart Association (SHA) guidelines for the management of heart failure

Heart failure (HF) is the leading cause of morbidity and mortality worldwide and negatively impacts quality of life, healthcare costs, and longevity. Although data on HF in the Arab population are scarce, recently developed regional registries are a step forward to evaluating the quality of current patient care and providing an overview of the clinical picture. Despite the burden of HF in Saudi Arabia, there are currently no standardized protocols or guidelines for the management of patients with acute or chronic heart failure. Therefore, the Heart Failure Expert Committee, comprising 13 local specialists representing both public and private sectors, has developed guidelines to address the needs and challenges for the diagnosis and treatment of HF in Saudi Arabia. The ultimate aim of these guidelines is to assist healthcare professionals in delivering optimal care and standardized clinical practice across Saudi Arabia.

Amiodarone and thyroid physiology, pathophysiology, diagnosis and management

Although amiodarone is considered the most effective antiarrhythmic agent, its use is limited by a wide variety of potential toxicities. The purpose of this review is to provide a comprehensive "bench to bedside" overview of the ways amiodarone influences thyroid function. We performed a systematic search of MEDLINE to identify peer-reviewed clinical trials, randomized controlled trials, meta-analyses, and other clinically relevant studies. The search was limited to English-language reports published between 1950 and 2017. Amiodarone was searched using the terms adverse effects, hypothyroidism, myxedema, hyperthyroidism, thyroid storm, atrial fibrillation, ventricular arrhythmia, and electrical storm. Google and Google scholar as well as bibliographies of identified articles were reviewed for additional references. We included 163 germane references in this review. Because amiodarone is one of the most frequently prescribed antiarrhythmic drugs in the United States, the mechanistic, diagnostic and therapeutic information provided is relevant for practicing clinicians in a wide range of medical specialties.

Atrial Fibrillation in Heart Failure-Diagnostic, Therapeutic, and Prognostic Relevance

PURPOSE OF REVIEW

Atrial fibrillation (AF) and heart failure (HF) commonly coexist and are associated with an increased risk of hospitalization, morbidity, and mortality. Both conditions develop into epidemics due to the ageing of the population and lead to poorer prognosis for the individual patients. Therapeutic strategies include treatment with oral anticoagulation, and rate and rhythm control concepts to prevent stroke and improve the cardiovascular outcome.

RECENT FINDINGS

Especially in HF patients, data suggest that catheter ablation of AF is superior to medical treatment. In patients with both AF and HF undergoing catheter ablation, significant increases in left ventricular ejection fraction and quality of life and decreases in related symptoms and major adverse cardiac events are reported. In addition, catheter ablation has been shown to reduce mortality and HF hospitalization in the medium term. For patients with AF and HF, an effective individualized therapeutic strategy to minimize potential complications and improve clinical outcomes is needed. Catheter ablation of AF seems to provide advantages in HF patients with AF. However, results of further long-term studies are awaited.

Dronedarone-Induced Cardiac Mitochondrial Dysfunction and Its Mitigation by Epoxyeicosatrienoic Acids

Dronedarone and amiodarone are structurally similar antiarrhythmic drugs. Dronedarone worsens cardiac adverse effects with unknown causes while amiodarone has no cardiac adversity. Dronedarone induces preclinical mitochondrial toxicity in rat liver and exhibits clinical hepatotoxicity. Here, we further investigated the relative potential of the antiarrhythmic drugs in causing mitochondrial injury in cardiomyocytes. Differentiated rat H9c2 cardiomyocytes were treated with dronedarone, amiodarone, and their respective metabolites namely N-desbutyldronedarone (NDBD) and N-desethylamiodarone (NDEA). Intracellular ATP content, mitochondrial membrane potential (Δψm), and inhibition of carnitine palmitoyltransferase I (CPT1) activity and arachidonic acid (AA) metabolism were measured in H9c2 cells. Inhibition of electron transport chain (ETC) activities and uncoupling of ETC were further studied in isolated rat heart mitochondria. Dronedarone, amiodarone, NDBD and NDEA decreased intracellular ATP content significantly (IC50 = 0.49, 1.84, 1.07, and 0.63 µM, respectively) and dissipated Δψm potently (IC50 = 0.5, 2.94, 12.8, and 7.38 µM, respectively). Dronedarone, NDBD, and NDEA weakly inhibited CPT1 activity while amiodarone (IC50 > 100 µM) yielded negligible inhibition. Only dronedarone inhibited AA metabolism to its regioisomeric epoxyeicosatrienoic acids (EETs) consistently and potently. NADH-supplemented ETC activity was inhibited by dronedarone, amiodarone, NDBD and NDEA (IC50 = 3.07, 5.24, 11.94, and 16.16 µM, respectively). Cytotoxicity, ATP decrease and Δψm disruption were ameliorated via exogenous pre-treatment of H9c2 cells with 11, 12-EET and 14, 15-EET. Our study confirmed that dronedarone causes mitochondrial injury in cardiomyocytes by perturbing Δψm, inhibiting mitochondrial complex I, uncoupling ETC and dysregulating AA-EET metabolism. We postulate that cardiac mitochondrial injury is one potential contributing factor to dronedarone-induced cardiac failure exacerbation.

Atrial Fibrillation Ablation Should Be First-line Therapy in Patients with Heart Failure Reduced Ejection Fraction

Catheter ablation for atrial fibrillation in patients with heart failure with reduced ejection fraction is associated with improvement in patient-centered outcomes, such as mortality, heart failure readmission, and atrial fibrillation recurrence, compared with standard medical therapy with or without device therapy. The evidence is not as robust in patients with atrial fibrillation and heart failure with preserved ejection fraction.

Atrial Fibrillation Ablation Should Be First-Line Therapy in Heart Failure Patients: CON

Heart failure (HF) and atrial fibrillation (AF) are the epidemics of the twenty-first century. These often coexist and are the cause of major morbidity and mortality. Management of these patients has posed a significant challenge to the medical community. Guideline-directed pharmacologic therapy for heart failure is important; however, there is no clear consensus on how best to treat AF with concomitant HF. In this article, we provide an in-depth review of the management of AF in patients with HF and provide insight as to why catheter ablation should not be the first line of therapy in this population.

Prediction and Management of Recurrences after Catheter Ablation in Atrial Fibrillation and Heart Failure

Catheter ablation is recommended in patients with symptomatic atrial fibrillation (AF) refractory to pharmacologic therapy. AF recurrence is common postablation, particularly in patients with heart failure, because of multiple structural and functional changes that can occur. Determining predictors of AF recurrence has become increasingly important. These include increased left atrial volume, termination of AF during the index ablation, electrocardiogram parameters, and serum biomarkers. Cardiac MRI can also determine the degree of scarring and left atrial sphericity, which is used in risk prediction scores. In patients with recurrence, further treatment options include pharmacologic therapy and atrioventricular nodal ablation with pacing.

Early choice for catheter ablation reduced readmission in management of atrial fibrillation: Impact of diagnosis-to-ablation time

BACKGROUND

The impact of delays in the treatment with radiofrequency catheter ablation (RFCA) for atrial fibrillation (AF) has not been well evaluated. The aim of this study was to investigate the impact of diagnosis-to-ablation time (DAT) on the long-term clinical outcomes after AF-RFCA.

METHODS

We enrolled 1206 consecutive patients undergoing first-time RFCA for AF. The study population was divided into 2 groups based on DAT: short (<3 years) (N = 675) and long (>3 years) (N = 531) DAT groups.

RESULTS

Mean follow-up duration was 5.0 ± 2.5 years. The 5-year event-free rates from recurrent atrial tachyarrhythmias after the first and second RFCAs were significantly higher in short DAT group than in long DAT group (60.2% versus 48.3%, log-rank P < 0.001; 83.2% versus 75.2%, log-rank P = 0.02, respectively), leading to reduced cardiovascular hospitalization in short DAT group. After adjusting baseline differences, short DAT was independently associated with lower arrhythmia recurrence rates after the first and second RFCAs (hazard ratio [HR] 0.72, 95% confidence interval [CI] 0.60-0.86 and HR 0.72, 95%CI 0.55-0.95, respectively). There were no significant differences between the 2 groups in the event-free rates from all-cause and cardiovascular deaths, heart failure hospitalization, and ischemic stroke. However, among patients with a history of heart failure or reduced left ventricular function, the event-free rate from heart failure readmission was significantly higher in short DAT group (85.0% versus 61.0%, P = 0.004).

CONCLUSIONS

In the management of AF, early RFCA was associated with significantly lower arrhythmia recurrence compared with delayed RFCA, leading to reduced cardiovascular hospitalization, especially in heart failure patients.

Heart failure progression and mortality in atrial fibrillation patients with preserved or reduced left ventricular ejection fraction

BACKGROUND

Atrial fibrillation (AF) worsens cardiovascular (CV) outcomes of heart failure (HF) and vice versa. The impact of rate or rhythm control strategies on HF progression and survival remains unclear.

METHODS

We examined the risk of HF progression in AF patients (pts) with a prior HF event and minimal or no HF burden (NYHA class 0 or 1). They were stratified into HF with a preserved left ventricular ejection fraction (≥ 40%, pEF) or reduced EF (< 40%, rEF). HF subgroups from the Rate and Rhythm arm were compared for the primary outcome of worsening HF or death (WHFD), total mortality, cardiovascular mortality, and cardiovascular hospitalizations.

RESULTS

Four hundred ninety-two AF pts (HFpEF = 349, HFrEF = 143) were analyzed. Baseline characteristics were generally comparable in the Rate and Rhythm arms of the two subgroups. Over a median follow-up of 4 years, HF recurred and worsened in 66.6% and 41.2% of pts by ≥ 1 and ≥ 2 NYHA classes, respectively. HF progression by even 1 NYHA class increased the mortality risk in HFpEF (hazard ratio (HR) 2.06; 95% confidence intervals (CI) 1.25-3.4; p = 0.004) and HFrEF (HR 1.9; 95% CI 0.99-3.66; p = 0.054). Cardiovascular hospitalization (CVH) increased in HFpEF (HR 3.67; 95% CI 2.56, 5.25; p < 0.0001) and HFrEF (HR 2.8; 95% CI 1.53-5.14; p = 0.0009). HF progression by 2 or more NYHA classes or death was significantly worse in pts with HFrEF with the Rate control strategy compared with the Rhythm control (HR 1.62; 95% CI 1.03-2.53; p = 0.036) but similar in pts with HFpEF (HR 0.88; 95% CI 0.64-1.21; p = 0.440).The time to first AF recurrence was longer in the Rhythm arms of both HF subgroups as compared with Rate (Figure, p < 0.05).

CONCLUSIONS

(1) HF progression in AF pts with a prior HF event confers significant mortality and CVH risk in both HFrEF and HFpEF populations. (2) HF progression is more pronounced with a Rate control strategy in AF pts with HFrEF, but is comparable to Rhythm control in AF pts with HFpEF. (3) A Rhythm control strategy may be desirable to reduce HF progression in pts with HFrEF and AF. Prospective clinical trials appear warranted to examine HF progression by treatment strategy in HFpEF and HFrEF populations with AF.

Management of Atrial Fibrillation in Patients with Heart Failure: Time to Implement Ablation Control

PURPOSE OF THE REVIEW

Atrial fibrillation (AF) in patients with heart failure and reduced systolic ejection fraction (HFrEF) is common and associated with increased morbidity and mortality, and managing AF in this population has been particularly challenging with sparse data regarding the optimal treatment strategy.

RECENT FINDINGS

Recent data suggests that rhythm control with catheter ablation can be of particular benefit to patients with coexisting AF and HFrEF. Recent randomized control trials actually suggest that catheter ablation could potentially improve mortality in this particular patient population. This is in stark contrast to the current practice recommendations that reserve catheter ablation for symptomatic AF in the general population. In this paper, we will review the most current randomized controlled studies using catheter ablation in HFrEF patients with the hope to increase awareness of the potential mortality benefits the need for prioritization of catheter ablation in HFrEF patients in the next AF management guidelines.

KSHF Guidelines for the Management of Acute Heart Failure: Part II. Treatment of Acute Heart Failure

The prevalence of heart failure (HF) is on the rise due to the aging of society. Furthermore, the continuous progress and widespread adoption of screening and diagnostic strategies have led to an increase in the detection rate of HF, effectively increasing the number of patients requiring monitoring and treatment. Because HF is associated with substantial rates of mortality and morbidity, as well as high socioeconomic burden, there is an increasing need for developing specific guidelines for HF management. The Korean guidelines for the diagnosis and management of chronic HF were introduced in March 2016. However, chronic and acute HF represent distinct disease entities. Here, we introduce the Korean guidelines for the management of acute HF with reduced or preserved ejection fraction. Part II of this guideline covers the treatment of acute HF.

KSHF Guidelines for the Management of Acute Heart Failure: Part III. Specific Management of Acute Heart Failure According to the Etiology and Co-morbidity

The prevalence of heart failure (HF) is on the rise due to the aging of society. Furthermore, the continuous progress and widespread adoption of screening and diagnostic strategies have led to an increase in the detection rate of HF, effectively increasing the number of patients requiring monitoring and treatment. Because HF is associated with substantial rates of mortality and morbidity, as well as high socioeconomic burden, there is an increasing need for developing specific guidelines for HF management. The Korean guidelines for the diagnosis and management of chronic heart failure (CHF) were introduced in March 2016. However, CHF and acute heart failure (AHF) represent distinct disease entities. Here, we introduce the Korean guidelines for the management of AHF with reduced or preserved ejection fraction. Part III of this guideline covers management strategies optimized according to the etiology of AHF and the presence of co-morbidities.

2018 Korean Guideline of Atrial Fibrillation Management

Atrial fibrillation (AF) is the most common sustained cardiac arrhythmia in the general population. The Korean Heart Rhythm Society organized a Korean AF Management Guideline Committee and analyzed all available studies regarding the management of AF, including studies on Korean patients. This guideline is based on recent data of the Korean population and the recent guidelines of the European Society of Cardiology, European Association for Cardio-Thoracic Surgery, American Heart Association, and Asia Pacific Heart Rhythm Society. Expert consensus or guidelines for the optimal management of Korean patients with AF were achieved after a systematic review with intensive discussion. This article provides general principles for appropriate risk stratification and selection of anticoagulation therapy in Korean patients with AF. This guideline deals with optimal stroke prevention, screening, rate and rhythm control, risk factor management, and integrated management of AF.

Meta-analysis of randomized controlled trials on atrial fibrillation ablation in patients with heart failure with reduced ejection fraction

BACKGROUND

The role of catheter ablation (CA) is increasingly recognized as a reasonable therapeutic option in patients with atrial fibrillation (AF) and heart failure (HF).

HYPOTHESIS

We aimed to compare CA to medical therapy in AF patients with HF with reduced ejection fraction (HFrEF).

METHODS

We searched the literature for randomized clinical trials comparing CA to medical therapy in this population.

RESULTS

Six trials with a total of 775 patients were included. AF was persistent in 95% of patients with a mean duration of 18.5 ± 23 months prior enrollment. The mean age was 62.2 ± 7.8 years, mostly males (83%) with mean left ventricular ejection fraction (LVEF) of 31.2 ± 6.7%. Compared to medical therapy, CA has significantly improved LVEF by 5.9% (Mean difference [MD] 5.93, confidence interval [CI] 3.59-8.27, P < 0.00001, I²  = 87%), quality of life, (MD -9.01, CI -15.56, -2.45, P = 0.007, I² = 47%), and functional capacity (MD 25.82, CI 5.46-46.18, P = 0.01, I² = 90%). CA has less HF hospital readmissions (odds ratio [OR] 0.5, CI 0.32-0.78, P = 0.002, I² = 0%) and death from any cause (OR 0.46, CI 0.29-0.73, P = 0.0009, I² = 0%). Freedom from AF during follow-up was higher in patients who had CA (OR 24.2, CI 6.94-84.41, P < 0.00001, I² = 81%.

CONCLUSION

CA was superior to medical therapy in patients with AF and HFrEF in terms of symptoms, hemodynamic response, and clinical outcomes by reducing AF burden. However, these findings are applicable to the very specific patients enrolled in these trials.

Atrial Fibrillation in Patients with Heart Failure: Current State and Future Directions

Heart failure affects nearly 26 million people worldwide. Patients with heart failure are frequently affected with atrial fibrillation, and the interrelation between these pathologies is complex. Atrial fibrillation shares the same risk factors as heart failure. Moreover, it is associated with a higher-risk baseline clinical status and higher mortality rates in patients with heart failure. The mechanisms by which atrial fibrillation occurs in a failing heart are incompletely understood, but animal studies suggest they differ from those that occur in a healthy heart. Data suggest that heart failure-induced atrial fibrosis and atrial ionic remodeling are the underlying abnormalities that facilitate atrial fibrillation. Therapeutic considerations for atrial fibrillation in patients with heart failure include risk factor modification and guideline-directed medical therapy, anticoagulation, rate control, and rhythm control. As recommended for atrial fibrillation in the non-failing heart, anticoagulation in patients with heart failure should be guided by a careful estimation of the risk of embolic events versus the risk of hemorrhagic episodes. The decision whether to target a rate-control or rhythm-control strategy is an evolving aspect of management. Currently, both approaches are good medical practice, but recent data suggest that rhythm control, particularly when achieved through catheter ablation, is associated with improved outcomes. A promising field of research is the application of neurohormonal modulation to prevent the creation of the "structural substrate" for atrial fibrillation in the failing heart.

Effects of dronedarone on all-cause mortality and on cardiovascular events in patients treated for atrial fibrillation: a meta-analysis of RCTs

INTRODUCTION

The efficacy and safety profiles of the dronedarone were rather praised when the molecule was placed on the market (2009). However, there are today some safety concerns (in particular, risk of liver toxicity) that have led to limit the use of this drug to paroxysmal or persistent atrial fibrillation, and to exclude it from therapy protocols for ventricular tachyarrhythmias. The aim of the present study was to explore some efficacy and safety endpoints concerning dronedarone, by analyzing the evidence derived from quantitative evaluation (meta-analysis) of literature data.

EVIDENCE ACQUISITION

We comprised in the meta-analysis exclusively randomized controlled trials (RCTs) that reported relevant clinical outcomes with dronedarone. In addition, eligible RCTs had to have randomized 100 patients at least in order to have adequate statistical power, and they had to have clearly reported the outcomes of interest. Primary efficacy outcomes were a) all-cause mortality,b) major acute cardiovascular events and c) worsening heart failure. Secondary outcomes of interest were ventricular tachyarrhythmias, stroke and systemic embolism. We performed a number of sensitivity analyses to better ascertain the sources of heterogeneity. We also performed a number of subgroup analyses.

EVIDENCE SYNTHESIS

At the end of the selection process, the studies regarded suitable for meta-analysis were seven. Dronedarone use was not associated with any significant advantage as regards all-cause mortality(pooled odds ratio =1.31; 95% CI: 0.78 to 2.18; P= 0.31) and major cardiovascular events (pooled odds ratio=1.45; 95% CI: 0.7 to 3.01; P=0.28), as well as regarding the endpoint" worsening heart failure" (pooled odds ratio =1.32; 95% CI: 0.87 to 2.01; P= 0.20). Moreover, using subgroup analyses, in patients with permanent AF, dronedarone use was associated with increased all-cause mortality compared to placebo(P=0.03),as well as with higher risk of major acute cardiovascular events (P=0.04) and episodes of worsening heart failure(P=0.02). In addition, when data from ATHENA study were excluded, dronedarone use was associated with increased all-cause mortality (post exclusion pooled odds ratio=1.77; 95% CI: 1.15 to 2.72; P=0.0089), increased risk of major cardiovascular events (post exclusion pooled odds ratio=2.16; 95% CI: 1.34 to 3.47; P= 0.0014) and increased risk of worsening heart failure(post exclusion pooled odds ratio= 1.618; 95% CI: 1.14 to 2.3; P=0.006).

CONCLUSIONS

In our meta-analysis, dronedarone did not provide any significant benefit with regard to all-cause mortality and major cardiovascular events, as well as regarding the risk of worsening heart failure. Sensitivity analyses then showed that the exclusion of a study, namely ATHENA study, caused a shift in the overall odds ratio, so as to convert the dronedarone use to the ominous role of predictor of higher mortality, worse cardiovascular morbidity and increased risk of worsening heart failure. Thus, dronedarone should be used with caution as second-line medication and exclusively for the secondary prevention of paroxysmal or persistent atrial fibrillation, in patients without signs or symptoms of cardiac decompensation, preferably for limited periods of time and under assiduous clinical and laboratory surveillance.

Emerging role of amiodarone and dronedarone, as antiarrhythmic drugs, in treatment of leishmaniasis

Leishmaniasis is a group of human and animal diseases causing 20,000-40,000 annual deaths and its etiological agents belong to the Leishmania genus. The most current treatment against leishmaniasis is chemotherapy. Pentavalent antimonials such as glucantime and pentostam have been administrated as the first-line drugs in treatment of various forms of leishmaniasis. The second-line drugs such as amphotericin B, liposomal amphotericin B, miltefosine, pentamidine, azole drugs and paromomycin are used in resistant cases to pentavalent antimonials. Because of drawbacks of the first-line and second-line drugs including adverse side effects on different organs, increasing resistance, high cost, need to hospitalization and long-term treatment, it is necessary to find an alternative drug for leishmaniasis treatment. Several investigations have reported the effectiveness of amiodarone, the most commonly used antiarrhythmic drug, against fungi, Trypanosomes and Leishmania spp. in vitro, in vivo and clinical conditions. Moreover, the beneficial effects of dronedarone, amiodarone analogues, against Trypanosoma cruzi and Leishmania mexicana have recently been demonstrated and such treatment regimens resulted in lower side effects. The anti- leishmanial and anti- trypanosomal effectiveness of amiodarone and dronedarone has been attributed to destabilization of intracellular Ca²⁺ homeostasis, inhibition of sterol biosynthesis and collapse of mitochondrial membrane potential. Because of relative low cost, excellent pharmacokinetic properties, easy accessibility and beneficial effects of amiodarone and dronedarone on leishmaniasis, they are proper candidates to replace the current drugs used in leishmaniasis treatment.

Pacing Treatment of Atrial Fibrillation Patients with Heart Failure: His Bundle Pacing Combined with Atrioventricular Node Ablation

As an alternative to antiarrhythmic drugs and catheter ablation of atrial fibrillation (AF) for rate and rhythm control, pacing combined with atrioventricular node (AVN) ablation is suitable for many AF patients with heart failure (HF) who suffer from symptoms despite optimal medical therapy or have failed AF ablation. Studies have demonstrated His bundle pacing in conjunction with AVN ablation to treat refractory AF patients with HF provide long-term clinical benefits. Here we introduce the clinical application and procedures of His bundle pacing and AVN ablation.

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.

Mechanisms and Drug Development in Atrial Fibrillation

Atrial fibrillation is a highly prevalent cardiac arrhythmia and the most important cause of embolic stroke. Although genetic studies have identified an increasing assembly of AF-related genes, the impact of these genetic discoveries is yet to be realized. In addition, despite more than a century of research and speculation, the molecular and cellular mechanisms underlying AF have not been established, and therapy for AF, particularly persistent AF, remains suboptimal. Current antiarrhythmic drugs are associated with a significant rate of adverse events, particularly proarrhythmia, which may explain why many highly symptomatic AF patients are not receiving any rhythm control therapy. This review focuses on recent advances in AF research, including its epidemiology, genetics, and pathophysiological mechanisms. We then discuss the status of antiarrhythmic drug therapy for AF today, reviewing molecular mechanisms, and the possible clinical use of some of the new atrial-selective antifibrillatory agents, as well as drugs that target atrial remodeling, inflammation and fibrosis, which are being tested as upstream therapies to prevent AF perpetuation. Altogether, the objective is to highlight the magnitude and endemic dimension of AF, which requires a significant effort to develop new and effective antiarrhythmic drugs, but also improve AF prevention and treatment of risk factors that are associated with AF complications.

Integration of "omics" techniques: Dronedarone affects cardiac remodeling in the infarction border zone

Dronedarone improves microvascular flow during atrial fibrillation and reduces the infarct size in acute models of myocardial infarction. However, dronedarone might be harmful in patients with recent decompensated heart failure and increases mortality in patients with permanent atrial fibrillation. A pathophysiological explanation for these discrepant data is lacking. This study investigated the effects of dronedarone on gene and protein expression in the infarcted area and border zone in pigs subjected to anterior ischemia/reperfusion myocardial infarction. The ischemia/reperfusion myocardial infarction was induced in 16 pigs. Eight pigs were treated with dronedarone for 28 days after myocardial infarction, the remaining pigs served as control. Microarray-based transcriptome profiling and 2D-DIGE-based proteome analysis were used to assess the effects of dronedarone on left ventricular gene expression in healthy (LV), infarcted (MI), and border zone tissue. Selected targets were validated by RT-qPCR or immunoblot analyses, with special emphasize given to the transcriptome/proteome overlap. Combined "omics" analysis was performed to identify most significant disease and function charts affected by dronedarone and to establish an integrated network. The levels of 879 (BZ) or 7 (MI) transcripts and 51 (LV) or 15 (BZ) proteins were significantly altered by dronedarone, pointing to a substantial efficacy of dronedarone in the border zone. Transcriptome and proteome data indicate that dronedarone influences post-infarction remodeling processes and identify matricellular proteins as major targets of dronedarone in this setting. This finding is fully supported by the disease and function charts as well as by the integrated network established by combined "omics". Dronedarone therapy alters myocardial gene expression after acute myocardial infarction with pronounced effects in the border zone. Dronedarone promotes infarct healing via regulation of periostin and might contribute to the limitation of its expansion as well as cardiac rupture. Thus, there are no experimental hints that dronedarone per se has direct harmful effects after MI in ventricular tissue. Impact statement Dronedarone reduced the infarct size in models of acute myocardial infarction (MI). Here, we show that dronedarone attenuates many of the substantial changes in gene expression that are provoked by acute myocardial infarction (AMI) in pigs. Dronedarone modifies the expression of gene panels related to post-infarction cardiac healing and remodeling processes and, most remarkably, this occurs predominantly in the infarction border-zone and much less so in the vital or infarcted myocardium. Combined "omics" identified matricellular proteins and ECM as major dronedarone-regulated targets and emphasizes their relevance for Disease Charts and Tox Function Charts associated with tissue remodeling and cellular movement. The results demonstrate dronedarone's capability of regulating cardiac repair and remodeling processes specifically in the infarction border zone and identify underlying mechanisms and pathways that might be employed in future therapeutic strategies to improve long-term cardiac tissue function and stability.

Substrates and potential therapeutics of ventricular arrhythmias in heart failure

Heart failure (HF) is a clinical syndrome characterized by ventricular contractile dysfunction. About 50% of death in patients with HF are due to fetal ventricular arrhythmias including ventricular tachycardia and ventricular fibrillation. Understanding ventricular arrhythmic substrates and discovering effective antiarrhythmic interventions are extremely important for improving the prognosis of patients with HF and reducing its mortality. In this review, we discussed ventricular arrhythmic substrates and current clinical therapeutics for ventricular arrhythmias in HF. Base on the fact that classic antiarrhythmic drugs have the limited efficacy, side effects, and proarrhythmic potentials, we also updated some therapeutic strategies for the development of potential new antiarrhythmic interventions for patients with HF.

Pharmacological Therapy for Rate and Rhythm Control for Atrial Fibrillation in 2017

In spite of the emergence of non-pharmacological approaches, medical therapy remains the primary modality of treatment for most patients with atrial fibrillation (AF). This review will look at evidence for rate and rhythm control approaches, and at factors that would help in choosing the appropriate treatment strategy for individual patients.

The role of hepatic cytochrome P450s in the cytotoxicity of dronedarone

Dronedarone is used to treat patients with cardiac arrhythmias and has been reported to be associated with liver injury. Our previous mechanistic work demonstrated that DNA damage-induced apoptosis contributes to the cytotoxicity of dronedarone. In this study, we examined further the underlying mechanisms and found that after a 24-h treatment of HepG2 cells, dronedarone caused cytotoxicity, G1-phase cell cycle arrest, suppression of topoisomerase II, and DNA damage in a concentration-dependent manner. We also investigated the role of cytochrome P450s (CYPs)-mediated metabolism in the dronedarone-induced toxicity using our previously established HepG2 cell lines expressing individually 14 human CYPs (1A1, 1A2, 1B1, 2A6, 2B6, 2C8, 2C9, 2C18, 2C19, 2D6, 2E1, 3A4, 3A5, and 3A7). We demonstrated that CYP3A4, 3A5, and 2D6 were the major enzymes that metabolize dronedarone, and that CYP3A7, 2E1, 2C19, 2C18, 1A1, and 2B6 also metabolize dronedarone, but to a lesser extent. Our data showed that the cytotoxicity of dronedarone was decreased in CYP3A4-, 3A5-, or 2D6-overexpressing cells compared to the control HepG2 cells, indicating that the parent dronedarone has higher potency than the metabolites to induce cytotoxicity in these cells. In contrast, cytotoxicity was increased in CYP1A1-overexpressing cells, demonstrating that CYP1A1 exerts an opposite effect in dronedarone's toxicity, comparing to CYP3A4, 3A5, or 2D6. We also studied the involvement of topoisomerase II in dronedarone-induced toxicity, and demonstrated that the overexpression of topoisomerase II caused an increase in cell viability and a decrease in γ-H2A.X induction, suggesting that suppression of topoisomerase II may be one of the mechanisms involved in dronedarone-induced liver toxicity.

Emerging pharmacotherapies for the treatment of atrial fibrillation

INTRODUCTION

The main aim of current research on the field of atrial fibrillation (AF) treatment is to find new antiarrhythmic drugs with less side effects. Areas covered: Dronedarone and vernakalant showed promising result in term of efficacy and safety in selected patients. Ranolazine and colchicine are obtaining a role as a potential antiarrhythmic drug. Ivabradine is used in experimental studies for the rate control of AF. Moreover, new compounds (vanoxerine, moxonidine, budiodarone) are still under investigation. Monoclonal antibodies or selective antagonist of potassium channel are under investigation for long term maintenance of sinus rhythm. Clinical evidence and new pharmacological investigation on new drugs will be accurately reviewed in this article. Expert opinion: Dronedarone use is not recommended in patients with symptomatic heart failure (HF), NYHA class III-IV, depressed ventricular function and permanent AF, especially in patients assuming a concomitant therapy with digoxin. Vernakalant had superior efficacy than amiodarone, flecainide and propafenone in single studies and similar efficacy to direct current cardioversion. Several of the developing drugs examined in this paper show an interesting potential, in particular the research on selective ionic channel inhibition and on compounds which reduce the inflammation state, especially after ablation or surgery.

Atrial Fibrillation: Beyond Rate Control

Atrial fibrillation is the most common cardiac dysrhythmia encountered in the primary care setting. Although a rate control strategy is pursued by physicians for the initial treatment of atrial fibrillation, the efficacy of a rhythm control approach is often undervalued despite offering effective treatment options. There are many pharmacological therapies available to patients, with drug choice often dictated by safety concerns (toxicities and proarrhythmic adverse effects) as well as patient characteristics and comorbidities. This article presents a simplified approach to understanding the rhythm control strategy, including the advantages and disadvantages of various antiarrhythmic drugs and common drug-drug interactions encountered in the primary care setting.

New formula for defining "normal" and "prolonged" QT in patients with bundle branch block

OBJECTIVES

To predict the QT interval in the presence of normal QRS for patients with left bundle branch block (LBBB).

BACKGROUND

There is no acceptable method for simple and reliable QT correction for patients with bundle branch block (BBB).

METHODS

We measured the QT interval in patients with new onset LBBB who had a recent electrocardiogram with narrow QRS for comparison. 48 patients who developed in-hospital LBBB were studied. Patients who had similar heart rate before and after LBBB were included. We used linear regression, the Bogossian method, and our new fixed QRS replacement method to evaluate the most reliable correction method.

RESULTS

JTc (QTc-QRS) interval was preserved before and after LBBB (328.9 ± 25.4 ms before LBBB vs. 327.3 ms post LBBB (p = 0.550). Mean predicted preLBBB QTc difference was 1.3 ms, -21.3 ms and 1.6 ms for the three methods respectively (p < 0.001 for Bogossian comparison with the other methods). Coefficients of correlation (R) between actual preLBBB QTc with predicted preLBBB QTc were 0.707, 0.683 and 0.665 respectively (p > 0.3 for R comparisons between all methods). The average absolute difference in preLBBB QTc was 15.5 ms and 16.7 ms for the regression and fixed-gender methods (p value between the two = 0.321) and 25.5 ms for the Bogossian method, which was found to be significantly underperforming.

CONCLUSIONS

In patients with LBBB, replacing of the QRS duration after deriving the QTc interval with a fixed value of 88 ms for female and 95 ms for male provides a simple and reliable method for predicting the QTc before the development of LBBB.

Ablation for Atrial Fibrillation in Heart Failure with Reduced Ejection Fraction

AF and heart failure with reduced ejection fraction (HFrEF) frequently coexist. Catheter ablation is an increasingly utilised treatment strategy for patients with AF and can be safely performed and is effective in achieving sinus rhythm for patients with HFrEF. Successful ablation may result in improved LV function, clinical heart failure status, quality of life and possibly even mortality. This review summarises the literature analysing efficacy, safety and outcomes of AF ablation for patients with HFrEF.

Treatment of Atrial Fibrillation in Patients with Co-existing Heart Failure and Reduced Ejection Fraction: Time to Revisit the Management Guidelines?

AF in patients with heart failure and reduced ejection fraction (HFrEF) is common and is associated with an increased risk of stroke, heart failure hospitalisation and all-cause mortality. Rhythm control of AF in this population has been traditionally limited to the use of antiarrhythmic drugs. Clinical trials assessing superiority of pharmacological rhythm control over rate control have been largely disappointing. Catheter ablation has emerged as a viable alternative to pharmacological rhythm control in symptomatic AF and has enjoyed significant technological advancements over the past decade. Recent clinical trials have suggested that catheter ablation is superior to pharmacological interventions in patients with co-existing AF and HFrEF. In this article, we will review the therapeutic options for AF in patients with HFrEF in the context of the latest clinical trials beyond the current established guidelines.

Newly developed atrial fibrillation progresses to a more severe INTERMACS score in a patient with advanced heart failure due to dilated cardiomyopathy

We have presented a case of advanced HF, in which newly developed AF hastened the timing of the implantation of mechanical support. Newly developed AF in advanced HF may be intractable by medical therapies and could be a key event that determines the timing of mechanical support.

Dronedarone produces early regression of myocardial remodelling in structural heart disease

Background and aims

Left ventricular hypertrophy (LVH) in hypertension is associated with a greater risk of sustained supraventricular/atrial arrhythmias. Dronedarone is an antiarrhythmic agent that was recently approved for the treatment of atrial fibrillation. However, its effect on early regression of LVH has not been reported. We tested the hypothesis that short-term administration of dronedarone induces early regression of LVH in spontaneously hypertensive rats (SHR_s).

Methods

Ten-month-old male SHR_s were randomly assigned to an intervention group (SHR-D), where animals received dronedarone treatment (100 mg/kg) for a period of 14 days, or to a control group (SHR) where rats were given vehicle. A third group with normotensive control rats (WKY) was also added. At the end of the treatment with dronedarone we studied the cardiac anatomy and function in all the rats using transthoracic echocardiogram, cardiac metabolism using the PET/CT study (2-deoxy-2[18F]fluoro-D-glucose) and cardiac structure by histological analysis of myocyte size and collagen content.

Results

The hypertensive vehicle treated SHR rats developed the classic cardiac pattern of hypertensive cardiomyopathy as expected for the experimental model, with increases in left ventricular wall thickness, a metabolic shift towards an increase in glucose use and increases in myocyte and collagen content. However, the SHR-D rats showed statistically significant lower values in comparison to SHR group for septal wall thickness, posterior wall thickness, ventricular mass, glucose myocardial uptake, size of left ventricular cardiomyocytes and collagen content. All these values obtained in SHR-D rats were similar to the values measured in the normotensive WKY control group.

Conclusion

The results suggest by three alternative and complementary ways (analysis of anatomy and cardiac function, metabolism and histological structure) that dronedarone has the potential to reverse the LVH induced by arterial hypertension in the SHR model of compensated ventricular hypertrophy.

Have the Findings from Clinical Risk Prediction and Trials Any Key Messages for Safety Pharmacology?

Anti-arrhythmic drugs are a mainstay in the management of symptoms related to arrhythmias, and are adjuncts in prevention and treatment of life-threatening ventricular arrhythmias. However, they also have the potential for pro-arrhythmia and thus the prediction of arrhythmia predisposition and drug response are critical issues. Clinical trials are the latter stages in the safety testing and efficacy process prior to market release, and as such serve as a critical safeguard. In this review, we look at some of the lessons to be learned from approaches to arrhythmia prediction in patients, clinical trials of drugs used in the treatment of arrhythmias, and the implications for the design of pre-clinical safety pharmacology testing.

How robust are clinical trials in heart failure?

Aims

Guidelines for the management of chronic heart failure (CHF) cite the results of randomized controlled trials (RCTs) to support treatment recommendations. The significance of an observed treatment-effect relies on the use of a boundary P-value, most commonly P < 0.05. There is concern about relying on arbitrary threshold P-values to report results as 'statistically significant'. The 'fragility index' (FI) has been proposed as an additional measure of the robustness of trial findings. FI is the minimum number of events needing to change from a non-event to an event in order to render a significant result non-significant. We calculated the FI to examine the robustness of statistically significant RCTs in CHF.

Methods and results

Two reviewers extracted data from RCTs supporting treatment recommendations in CHF guidelines. Twenty-five eligible trials were identified with a median sample size of 2331 patients (range 129-8399) and a median number of primary endpoints of 688.5 (range 88-2031). For the primary endpoint (analysed for 20 trials), the median FI was 26 (range 0-118). The FI was ≤10 in 7 (35%) of these 20 trials, and in 4 (20%) trials the number of patients lost to follow-up in the treatment group exceeded the FI.

Conclusion

The results of some large RCTs in CHF hinge on a small number of events. The FI offers an additional, easy to understand metric, which augments the standard reporting of boundary P-values for statistical significance. The FI helps in the interpretation of the robustness of the results of RCTs.

Drug Therapy in Adult Congenital Heart Disease

Adults with congenital heart disease are at risk for atrial and ventricular arrhythmias that can lead to an increased morbidity as well as mortality. When catheter ablation is not an option or unsuccessful, antiarrhythmic drugs are the mainstay of treatment. There is limited data on the use of antiarrhythmics in this population. The purpose of this article is to discuss the practical aspects of the use of antiarrhythmics in adults with congenital heart disease. Several tables have been provided to provide clinicians a reference for daily use.