A randomized trial of budiodarone in paroxysmal atrial fibrillation

Investigative agents for atrial fibrillation: agonists and stimulants, progress and expectations

INTRODUCTION

Atrial fibrillation (AF) is the most common type of cardiac arrhythmia. Its prevalence has increased due to worldwide populations that are aging in combination with the growing incidence of risk factors associated. Recent advances in our understanding of AF pathophysiology and the identification of nodal players involved in AF-promoting atrial remodeling highlights potential opportunities for new therapeutic approaches.

AREAS COVERED

This detailed review summarizes recent developments in the field antiarrhythmic drugs in the field AF.

EXPERT OPINION

The current situation is far than optimal. Despite clear unmet needs in drug development in the field of AF treatment, the current development of new drugs is absent. The need for a molecule with absence of cardiac and non-cardiac toxicity in the short and long term is a limitation in the field. Improvement in the understanding of AF genetics, pathophysiology, molecular alterations, big data and artificial intelligence with the objective to provide a personalized AF treatment will be the cornerstone of AF treatment in the coming years.

Advances in basic and translational research in atrial fibrillation

Atrial fibrillation (AF) is a very common cardiac arrhythmia with an estimated prevalence of 33.5 million patients globally. It is associated with an increased risk of death, stroke and peripheral embolism. Although genetic studies have identified a growing number of genes associated with AF, the definitive impact of these genetic findings is yet to be established. Several mechanisms, including electrical, structural and neural remodelling of atrial tissue, have been proposed to contribute to the development of AF. Despite over a century of exploration, the molecular and cellular mechanisms underlying AF have not been fully established. Current antiarrhythmic drugs are associated with a significant rate of adverse events and management of AF using ablation is not optimal, especially in cases of persistent AF. This review discusses recent advances in our understanding and management of AF, including new concepts of epidemiology, genetics and pathophysiological mechanisms. We review the current status of antiarrhythmic drug therapy for AF, new potential agents, as well as mechanism-based AF ablation. This article is part of the theme issue 'The heartbeat: its molecular basis and physiological mechanisms'.

Antiarrhythmic drugs for atrial fibrillation: lessons from the past and opportunities for the future

Atrial fibrillation (AF) remains a highly prevalent and troublesome cardiac arrhythmia, associated with substantial morbidity and mortality. Restoration and maintenance of sinus rhythm (rhythm-control therapy) is an important element of AF management in symptomatic patients. Despite significant advances and increasing importance of catheter ablation, antiarrhythmic drugs (AADs) remain a cornerstone of rhythm-control therapy. During the past 50 years, experimental and clinical research has greatly increased our understanding of AADs. As part of the special issue on paradigm shifts in AF, this review summarizes important milestones in AAD research that have shaped their current role in AF management, including (i) awareness of the proarrhythmic potential of AADs; (ii) increasing understanding of the pleiotropic effects of AADs; (iii) the development of dronedarone; and (iv) the search for AF-specific AADs. Finally, we discuss short- and long-term opportunities for better AF management through advances in AAD therapy, including personalization of AAD therapy based on individual AF mechanisms.

Bucindolol Decreases Atrial Fibrillation Burden in Patients With Heart Failure and the ADRB1 Arg389Arg Genotype

[Figure: see text].

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.

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.

Investigational antiarrhythmic agents: promising drugs in early clinical development

INTRODUCTION

Although there have been important technological advances for the treatment of cardiac arrhythmias (e.g., catheter ablation technology), antiarrhythmic drugs (AADs) remain the cornerstone therapy for the majority of patients with arrhythmias. Most of the currently available AADs were coincidental findings and did not result from a systematic development process based on known arrhythmogenic mechanisms and specific targets. During the last 20 years, our understanding of cardiac electrophysiology and fundamental arrhythmia mechanisms has increased significantly, resulting in the identification of new potential targets for mechanism-based antiarrhythmic therapy. Areas covered: Here, we review the state-of-the-art in arrhythmogenic mechanisms and AAD therapy. Thereafter, we focus on a number of antiarrhythmic targets that have received significant attention recently: atrial-specific K+-channels, the late Na+-current, the cardiac ryanodine-receptor channel type-2, and the small-conductance Ca2+-activated K+-channel. We highlight for each of these targets available antiarrhythmic agents and the evidence for their antiarrhythmic effect in animal models and early clinical development. Expert opinion: Targeting AADs to specific subgroups of well-phenotyped patients is likely necessary to detect improved outcomes that may be obscured in the population at large. In addition, specific combinations of selective AADs may have synergistic effects and may enable a mechanism-based tailored antiarrhythmic therapy.

Atrial fibrillation and heart failure: update 2015

Heart failure (HF) and atrial fibrillation (AF) commonly coexist, adversely affect mortality, and impose a significant burden on healthcare resources. The presence of AF and HF portends a poor prognosis as well as an increased thromboembolic risk. In patients whose AF is symptomatic, rhythm restoration with either antiarrhythmic drugs or procedural therapies (e.g., pulmonary vein isolation, either catheter-based or surgical) should be considered for symptom improvement, though a mortality benefit has yet to be demonstrated. Emerging evidence suggests that non-pharmacological treatment for AF (including catheter based ablation, hybrid surgical techniques, and atrioventricular node ablation with biventricular pacing) may be of value in improving HF patients' quality of life.

Novel methods and technologies for 21st-century clinical trials: a review

IMPORTANCE

New technologies are rapidly reshaping health care. However, their effect on drug development to date generally has been limited.

OBJECTIVES

To evaluate disease modeling and simulation, alternative study design, novel objective measures, virtual research visits, and enhanced participant engagement and to examine their potential effects as methods and tools on clinical trials.

EVIDENCE REVIEW

We conducted a systematic search of relevant terms on PubMed (disease modeling and clinical trials; adaptive design, clinical trials, and neurology; Internet, clinical trials, and neurology; and telemedicine, clinical trials, and neurology), references of previous publications, and our files. The search encompassed articles published from January 1, 2000, through November 30, 2014, and produced 7976 articles, of which 22 were determined to be relevant and are included in this review.

FINDINGS

Few of these new methods and technologies have been applied to neurology clinical trials. Clinical outcomes, including cognitive and stroke outcomes, increasingly are captured remotely. Other therapeutic areas have successfully implemented many of these tools and technologies, including web-enabled clinical trials.

CONCLUSIONS AND RELEVANCE

Increased use of new tools and approaches in future clinical trials can enhance the design, improve the assessment, and engage participants in the evaluation of novel therapies for neurologic disorders.

A placebo-controlled, double-blind, randomized, multicenter study to assess the effects of dronedarone 400 mg twice daily for 12 weeks on atrial fibrillation burden in subjects with permanent pacemakers

Purpose

Dronedarone is a benzofuran derivative with a pharmacological profile similar to amiodarone but has a more rapid onset of action and a much shorter half-life (13–19 h). Our goal was to evaluate the efficacy of dronedarone in atrial fibrillation (AF) patients using dual-chamber pacemakers capable of quantifying atrial fibrillation burden.

Methods

Pacemakers were adjusted to optimize AF detection. Patients with AF burden >1 % were randomized to dronedarone 400 mg twice daily (BID) or placebo. Pacemakers were interrogated after 4 and 12 weeks of treatment. The primary endpoint was the change in AF burden from baseline over the 12-week treatment period. Patients with permanent AF, severe/recently decompensated heart failure, and current use of antiarrhythmic drugs were excluded. AF burden was assessed by a core laboratory blinded to treatment assignment.

Results

From 285 patients screened, 112 were randomized (mean age 76 years, 60 % male, 84 % hypertensive, 65 % with sick sinus syndrome, 26 % with diabetes mellitus type II, 15 % with heart failure). Baseline mean (SEM) AF burden was 8.77 % (0.16) for placebo and 10.14 % (0.17) for dronedarone. Over the 12-week study period, AF burden compared to baseline decreased by 54.4 % (0.22) (P = 0.0009) with dronedarone and trended higher by 12.8 % (0.16) (P = 0.450) with placebo. The absolute change in burden was decreased by 5.5 % in the dronedarone group and increased by 1.1 % in the placebo group. Heart rate during AF was reduced to approximately 4 beats/min with dronedarone (P = 0.285). Adverse events were higher with dronedarone compared to placebo (65 vs 56 %).

Conclusions

Dronedarone reduced pacemaker-assessed the relative AF burden compared to baseline and placebo by over 50 % during the 12-week observation period.

Rhythm control in heart failure patients with atrial fibrillation: contemporary challenges including the role of ablation

Because nonpharmacological interventions likely alter the risks and benefits associated with rhythm control, this paper reviews the role of current rhythm control strategies in atrial fibrillation. This report also focuses on the specific limitations of pharmacological interventions and the utility of percutaneous ablation in this growing population of patients with concomitant atrial fibrillation and heart failure.

Pacemaker diagnostics in atrial fibrillation: limited usefulness for therapy initiation in a pacemaker practice

AIM

We aimed to determine the practical value of pacemaker diagnostics for atrial fibrillation (AF) in an unselected general pacemaker practice, specifically workflow and initiation of anticoagulation or antiarrhythmic drug (AAD) therapy.

METHODS

We prospectively followed consecutive pacemaker interrogations over a period of 1 year to identify patients with AF (burden from 1% to 99%). We contacted referring physicians with AF details, and then determined whether the information resulted in therapeutic changes.

RESULTS

Of the 1,100 pacemakers interrogated, 728 were dual chamber (DDDs) with AF diagnostic capability. AF was recorded in 73 (10%) but seven had limited information, leaving 66 patients; of these, 42 (63%) patients were already anticoagulated and in five (7%) patients, anticoagulation had been stopped because of complications. Initial diagnosis of AF was made by the pacemaker in 17 patients (26% of 66; 2% of 728); four (6% of 66) patients were newly initiated on anticoagulation. Of the 66 patients, 17 patients were already on AADs; 49 (74%) had satisfactory rate control or had other issues; only two (3% of 66; 0.3% of 728) received new AADs.

CONCLUSIONS

Of 728 patients with DDD pacemakers, only 17 were newly discovered to have AF, and six (0.8%) had changes in medications based on the pacemaker data. Adding pacemaker-derived data to existing clinical information had little therapeutic impact, due to a combination of cumbersome workflow, and because AF was usually known to practitioners. Developments in automated monitoring systems may provide more accessible and therapeutically useful information.

AF burden is important - fact or fiction?

Asymptomatic atrial fibrillation (AF) is common and in view of its prognostic impact (the same as of clinically overt AF) knowledge of the overall AF burden (defined as the amount of time spent in AF) appears to be important, both for scientific and clinical reasons. Data collected on more than 12,000 patients indicate that cardiac implantable electrical devices (CIEDs) are validated tools for measuring AF burden and that AF burden is associated with an increased risk of stroke. A maximum daily AF burden of ≥ 1 h carries important negative prognostic implications and may be a clinically relevant parameter for improving risk stratification for stroke. Decision-making should primarily consider the context in which asymptomatic, subclinical arrhythmias are detected (i.e. primary or secondary prevention of stroke and systemic embolism) and the risk profile of every individual patient with regard to thromboembolic and haemorrhagic risk, as well as patient preferences and values. Continuous monitoring using CIEDs with extensive data storage capabilities allow in-depth study of the temporal relationship between AF and ischaemic stroke. The relationships between AF and stroke are complex. AF is certainly a risk factor for cardioembolic stroke, with a cause-effect relationship between the arrhythmia and a thromboembolic event, the latter being related to atrial thrombi. However, AF can also be a simple 'marker of risk', with a non-causal association between the arrhythmia and stroke, the latter being possibly related to atheroemboli from the aorta, the carotid arteries or from other sources.

Antiarrhythmic drugs 2013: state of the art

Antiarrhythmic drugs are widely used, but are of modest efficacy and have important side effects. However, even with the advance of catheter ablation for atrial fibrillation and ventricular tachycardia, antiarrhythmic drugs remain an important tool for treating arrhythmias. Antiarrhythmic drug development has remained slow despite much effort given our limited understanding of what role various ionic currents play in arrhythmogenesis and how they are modified by arrhythmias. This review will focus on promising new antiarrhythmic drugs undergoing clinical investigation or currently approved for clinical use, including amiodarone analogues, agents with novel ionic targets, and new drug combinations.

The Effects of Ranolazine on Paroxysmal Atrial Fibrillation in Patients with Coronary Artery Disease: A Preliminary Observational Study

The impact of ranolazine, an anti-ishemic agent with antiarrhythmic properties, on paroxysmal atrial fibrillation (PAF) in patients with coronary artery disease (CAD) remains unclear. Pacing devices can be useful tools for disclosing even asymptomatic PAF. Purpose of this study is to assess the effect of ranolazine on atrial fibrillation (AF), in patients with CAD, PAF and a dual-chamber pacemaker. We studied 74 patients with CAD, PAF, and sick sinus syndrome or atrio-ventricular block, treated with pacemakers capable to detect PAF episodes. The total time in AF, AF burden, and the number of PAF episodes within the last 6 months before enrolment in the study, mean AF duration per episode, and the QTc interval were initially assessed. Subsequently, patients were randomized into additional treatment with ranolazine (375 mg twice daily) or placebo. Following six months of treatment, all parameters were reassessed and compared to those before treatment. Ranolazine was associated with shorter total AF duration (81.56±45.24 hours versus 68.71±34.84 hours, p=0.002), decreased AF burden (1.89±1.05% versus 1.59±0.81%, p=0.002), and shortened mean AF duration (1.15±0.41 hours versus 0.92±0.35 hours, p=0.01). In the placebo group no such differences were observed. In both groups, no significant differences in the number of PAF episodes and QTc duration were observed. We conclude that in patients with CAD and PAF, ranolazine reduces the total time in AF, AF burden, and mean AF duration. These findings may imply additional antiarrhythmic properties of ranolazine on atrial myocardium and might indicate the necessity of its use in ischemic patients with PAF.

Advances in the management of atrial fibrillation

Atrial fibrillation (AF) is the most common arrhythmia worldwide, increasing in incidence with the aging population. Substantial morbidity and mortality accompany its diagnosis. Management should focus on rate and rhythm management, on reducing thromboembolic risk, and also potentially on targeting the mechanisms responsible for its perpetuation. Current antiarrhythmic therapy has only modest efficacy and substantial side effects, and anticoagulation regimes are cumbersome and require regular monitoring. Novel anticoagulants and antiarrhythmics hold the promise of improved efficacy and safety. This review covers current therapy for AF, major advances in pharmacological management and future directions for therapy.