Pharmacologic cardioversion of recent-onset atrial fibrillation: a systematic review and network meta-analysis

External electrical and pharmacological cardioversion for atrial fibrillation, atrial flutter or atrial tachycardias: a network meta-analysis

BACKGROUND

Atrial fibrillation (AF) is the most frequent sustained arrhythmia. Cardioversion is a rhythm control strategy to restore normal/sinus rhythm, and can be achieved through drugs (pharmacological) or a synchronised electric shock (electrical cardioversion).

OBJECTIVES

To assess the efficacy and safety of pharmacological and electrical cardioversion for atrial fibrillation (AF), atrial flutter and atrial tachycardias.

SEARCH METHODS

We searched CENTRAL, MEDLINE, Embase, Conference Proceedings Citation Index-Science (CPCI-S) and three trials registers (ClinicalTrials.gov, WHO ICTRP and ISRCTN) on 14 February 2023.

SELECTION CRITERIA

We included randomised controlled trials (RCTs) at the individual patient level. Patient populations were aged ≥ 18 years with AF of any type and duration, atrial flutter or other sustained related atrial arrhythmias, not occurring as a result of reversible causes.

DATA COLLECTION AND ANALYSIS

We used standard Cochrane methodology to collect data and performed a network meta-analysis using the standard frequentist graph-theoretical approach using the netmeta package in R. We used GRADE to assess the quality of the evidence which we presented in our summary of findings with a judgement on certainty. We calculated differences using risk ratios (RR) and 95% confidence intervals (CI) as well as ranking treatments using a P value. We assessed clinical and statistical heterogeneity and split the networks for the primary outcome and acute procedural success, due to concerns about violating the transitivity assumption.

MAIN RESULTS

We included 112 RCTs (139 records), from which we pooled data from 15,968 patients. The average age ranged from 47 to 72 years and the proportion of male patients ranged from 38% to 92%. Seventy-nine trials were considered to be at high risk of bias for at least one domain, 32 had no high risk of bias domains, but had at least one domain classified as uncertain risk, and one study was considered at low risk for all domains. For paroxysmal AF (35 trials), when compared to placebo, anteroapical (AA)/anteroposterior (AP) biphasic truncated exponential waveform (BTE) cardioversion (RR: 2.42; 95% CI 1.65 to 3.56), quinidine (RR: 2.23; 95% CI 1.49 to 3.34), ibutilide (RR: 2.00; 95% CI 1.28 to 3.12), propafenone (RR: 1.98; 95% CI 1.67 to 2.34), amiodarone (RR: 1.69; 95% CI 1.42 to 2.02), sotalol (RR: 1.58; 95% CI 1.08 to 2.31) and procainamide (RR: 1.49; 95% CI 1.13 to 1.97) likely result in a large increase in maintenance of sinus rhythm until hospital discharge or end of study follow-up (certainty of evidence: moderate). The effect size was larger for AA/AP incremental and was progressively smaller for the subsequent interventions. Despite low certainty of evidence, antazoline may result in a large increase (RR: 28.60; 95% CI 1.77 to 461.30) in this outcome. Similarly, low-certainty evidence suggests a large increase in this outcome for flecainide (RR: 2.17; 95% CI 1.68 to 2.79), vernakalant (RR: 2.13; 95% CI 1.52 to 2.99), and magnesium (RR: 1.73; 95% CI 0.79 to 3.79). For persistent AF (26 trials), one network was created for electrical cardioversion and showed that, when compared to AP BTE incremental energy with patches, AP BTE maximum energy with patches (RR 1.35, 95% CI 1.17 to 1.55) likely results in a large increase, and active compression AP BTE incremental energy with patches (RR: 1.14, 95% CI 1.00 to 1.131) likely results in an increase in maintenance of sinus rhythm at hospital discharge or end of study follow-up (certainty of evidence: high). Use of AP BTE incremental with paddles (RR: 1.03, 95% CI 0.98 to 1.09; certainty of evidence: low) may lead to a slight increase, and AP MDS Incremental paddles (RR: 0.95, 95% CI 0.86 to 1.05; certainty of evidence: low) may lead to a slight decrease in efficacy. On the other hand, AP MDS incremental energy using patches (RR: 0.78, 95% CI 0.70 to 0.87), AA RBW incremental energy with patches (RR: 0.76, 95% CI 0.66 to 0.88), AP RBW incremental energy with patches (RR: 0.76, 95% CI 0.68 to 0.86), AA MDS incremental energy with patches (RR: 0.76, 95% CI 0.67 to 0.86) and AA MDS incremental energy with paddles (RR: 0.68, 95% CI 0.53 to 0.83) probably result in a decrease in this outcome when compared to AP BTE incremental energy with patches (certainty of evidence: moderate). The network for pharmacological cardioversion showed that bepridil (RR: 2.29, 95% CI 1.26 to 4.17) and quindine (RR: 1.53, (95% CI 1.01 to 2.32) probably result in a large increase in maintenance of sinus rhythm at hospital discharge or end of study follow-up when compared to amiodarone (certainty of evidence: moderate). Dofetilide (RR: 0.79, 95% CI 0.56 to 1.44), sotalol (RR: 0.89, 95% CI 0.67 to 1.18), propafenone (RR: 0.79, 95% CI 0.50 to 1.25) and pilsicainide (RR: 0.39, 95% CI 0.02 to 7.01) may result in a reduction in this outcome when compared to amiodarone, but the certainty of evidence is low. For atrial flutter (14 trials), a network could be created only for antiarrhythmic drugs. Using placebo as the common comparator, ibutilide (RR: 21.45, 95% CI 4.41 to 104.37), propafenone (RR: 7.15, 95% CI 1.27 to 40.10), dofetilide (RR: 6.43, 95% CI 1.38 to 29.91), and sotalol (RR: 6.39, 95% CI 1.03 to 39.78) probably result in a large increase in the maintenance of sinus rhythm at hospital discharge or end of study follow-up (certainty of evidence: moderate), and procainamide (RR: 4.29, 95% CI 0.63 to 29.03), flecainide (RR 3.57, 95% CI 0.24 to 52.30) and vernakalant (RR: 1.18, 95% CI 0.05 to 27.37) may result in a large increase in maintenance of sinus rhythm at hospital discharge or end of study follow-up (certainty of evidence: low). All tested electrical cardioversion strategies for atrial flutter had very high efficacy (97.9% to 100%). The rate of mortality (14 deaths) and stroke or systemic embolism (3 events) at 30 days was extremely low. Data on quality of life were scarce and of uncertain clinical significance. No information was available regarding heart failure readmissions. Data on duration of hospitalisation was scarce, of low quality, and could not be pooled.

AUTHORS' CONCLUSIONS

Despite the low quality of evidence, this systematic review provides important information on electrical and pharmacological strategies to help patients and physicians deal with AF and atrial flutter. In the assessment of the patient comorbidity profile, antiarrhythmic drug onset of action and side effect profile versus the need for a physician with experience in sedation, or anaesthetics support for electrical cardioversion are key aspects when choosing the cardioversion method.

Safety and Effectiveness of Antidysrhythmic Drugs for Pharmacologic Cardioversion of Recent-Onset Atrial Fibrillation: a Systematic Review and Bayesian Network Meta-analysis

PURPOSE

The available evidence to determine which antidysrhythmic drug is superior for pharmacologic cardioversion of recent-onset (onset within 48 h) atrial fibrillation (AF) is uncertain. We aimed to identify the safest and most effective agent for pharmacologic cardioversion of recent-onset AF in the emergency department.

METHODS

We searched MEDLINE, Embase, and Web of Science from inception to February 21, 2023 (PROSPERO: CRD42018083781). Eligible studies were randomized controlled trials that enrolled adult participants with AF ≤ 48 h, compared a guideline-recommended antidysrhythmic drug with another antidysrhythmic drug or a different formulation of the same drug or placebo and reported specific adverse events. The primary outcome was immediate, serious adverse event - cardiac arrest, sustained ventricular tachydysrhythmia, atrial flutter 1:1 atrioventricular conduction, hypotension, and bradycardia. Additional analyses included the outcomes of conversion to sinus rhythm within 4 h and 24 h. We extracted data according to PRISMA-NMA and appraised trials using Cochrane RoB 2. We performed Bayesian network meta-analysis (NMA) using a Markov Chain Monte Carlo method with random-effect model and vague prior distribution to calculate odds ratios with 95% credible intervals. We assessed confidence using CINeMA. We used surface under the cumulative ranking curve (SUCRA) to rank agent(s).

RESULTS

The systematic review initially identified 5545 studies. Twenty-five studies met eligibility criteria, and 22 studies (n = 3082) provided data for NMA, which demonstrated that vernakalant (SUCRA = 70.9%) is most likely to be safest. Additional effectiveness NMA demonstrated that flecainide (SUCRA = 89.0%) is most likely to be superior for conversion within 4 h (27 studies; n = 2681), and ranolazine-amiodarone IV (SUCRA 93.7%) is most likely to be superior for conversion within 24 h (24 studies; n = 3213). Confidence in the NMA estimates is variable and limited mostly by within-study bias and imprecision.

CONCLUSIONS

Among guideline-recommended antidysrhythmic drugs, the combination of digoxin IV and amiodarone IV is definitely among the least safe for cardioversion of recent onset AF; flecainide, vernakalant, ibutilide, propafenone, and amiodarone IV are definitely among the most effective for cardioversion within 4 h; flecainide is definitely among the most effective for cardioversion within 24 h. Further, randomized controlled trials with predetermined and strictly defined, hemodynamic adverse event outcomes are recommended.

Real-world utilization of the pill-in-the-pocket method for terminating episodes of atrial fibrillation: data from the multinational Antiarrhythmic Interventions for Managing Atrial Fibrillation (AIM-AF) survey

AIMS

Atrial fibrillation (AF) is the most common sustained arrhythmia encountered in clinical practice. Episodes may stop spontaneously (paroxysmal AF); may terminate only via intervention (persistent AF); or may persist indefinitely (permanent AF) (see European and American guidelines, referenced below, for more precise definitions). Recently, there has been renewed interest in an approach to terminate AF acutely referred to as 'pill-in-the-pocket' (PITP). The PITP is recognized in both the US and European guidelines as an effective option using an oral antiarrhythmic drug for acute conversion of acute/recent-onset AF. However, how PITP is currently used has not been systematically evaluated.

METHODS AND RESULTS

The recently published Antiarrhythmic Interventions for Managing Atrial Fibrillation (AIM-AF) survey included questions regarding current PITP usage, stratified by US vs. European countries surveyed, by representative countries within Europe, and by cardiologists vs. electrophysiologists. This manuscript presents the data from this planned sub-study. Our survey revealed that clinicians in both the USA and Europe consider PITP in about a quarter of their patients, mostly for recent-onset AF with minimal or no structural heart disease (guideline appropriate). However, significant deviations exist. See the Graphical abstract for a summary of the data.

CONCLUSION

Our findings highlight the frequent use of PITP and the need for further physician education about appropriate and optimal use of this strategy.

Bayesian Network Meta-analysis of Randomized Controlled Trials on the Efficacy of Antiarrhythmics in the Pharmacological Cardioversion of Paroxysmal Atrial Fibrillation

PURPOSE

Since atrial fibrillation (AF) is one of the major arrhythmias managed in hospitals worldwide, it has a major impact on public health. The guidelines agree on the desirability of cardioverting paroxysmal AF episodes. This meta-analysis aims to answer the question of which antiarrhythmic agent is most effective in cardioverting a paroxysmal AF.

MATERIALS AND METHODS

A systematic review and Bayesian network meta-analysis, searching MEDLINE, Embase, and CINAHL, were performed, including randomized controlled trials (RCTs) enrolling a population of unselected adult patients with a paroxysmal AF that compared at least two pharmacological regimes to restore the sinus rhythm or a cardioversion agent against a placebo. The main outcome was efficacy in restoring sinus rhythm.

RESULTS

Sixty-one RCTs (7988 patients) were included in the quantitative analysis [deviance information criterion (DIC) 272.57; I² = 3%]. Compared with the placebo, the association verapamil-quinidine shows the highest SUCRA rank score (87%), followed by antazoline (86%), vernakalant (85%), tedisamil at high dose (i.e., 0.6 mg/kg; 80%), amiodarone-ranolazine (80%), lidocaine (78%), dofetilide (77%), and intravenous flecainide (71%). Taking into account the degree of evidence of each individual comparison between pharmacological agents, we have drawn up a ranking of pharmacological agents from the most effective to the least effective.

CONCLUSIONS

In comparing the antiarrhythmic agents used to restore sinus rhythm in the case of paroxysmal AF, vernakalant, amiodarone-ranolazine, flecainide, and ibutilide are the most effective medications. The verapamil-quinidine combination seems promising, though few RCTs have studied it. The incidence of side effects must be taken into account in the choice of antiarrhythmic in clinical practice.

CLINICAL TRIAL REGISTRATION

PROSPERO: International prospective register of systematic reviews, 2022, CRD42022369433 (Available from: https://www.crd.york.ac.uk/prospero/display_record.php?ID=CRD42022369433 ).

How to Optimize Cardioversion of Atrial Fibrillation

Cardioversion (CV) is an essential component of rhythm control strategy in the treatment of atrial fibrillation (AF). Timing of CV is an important manageable factor in optimizing the safety and efficacy of CV. Based on observational studies, the success rate of CV seems to be best (≈95%) at 12−48 h after the onset of arrhythmic symptoms compared with a lower success rate of ≈85% in later elective CV. Early AF recurrences are also less common after acute CV compared with later elective CV. CV causes a temporary increase in the risk of thromboembolic complications. Effective anticoagulation reduces this risk, especially during the first 2 weeks after successful CV. However, even during therapeutic anticoagulation, each elective CV increases the risk of stroke 4-fold (0.4% vs. 0.1%) during the first month after the procedure, compared with acute (<48 h) CV or avoiding CV. Spontaneous CVs are common during the early hours of AF. The short wait-and-see approach, up to 24−48 h, is a reasonable option for otherwise healthy but mildly symptomatic patients who are using therapeutic anticoagulation, since they are most likely to have spontaneous rhythm conversion and have no need for active CV. The probability of early treatment failure and antiarrhythmic treatment options should be evaluated before proceeding to CV to avoid the risks of futile CVs.

Effect of Early Pharmacologic Cardioversion vs. Non-early Cardioversion in the Patients With Recent-Onset Atrial Fibrillation Within 4-Week Follow-Up Period: A Systematic Review and Network Meta-Analysis

Background

Whether early pharmacologic cardioversion is necessary for recent-onset atrial fibrillation is still controversial. Current meta-analyses were limited to evaluating the effects within 24 h without sufficient considering longer follow-up outcomes. We aimed to compare the effect of early pharmacologic cardioversion and non-early cardioversion in patients with recent-onset atrial fibrillation within 4-weeks of follow-up.

Methods

We searched the Cochrane Library, EMBASE, MEDLINE, PubMed, Web of Science, ClinicalTrials.gov, and Clinicaltrialsregister. eu for randomized controlled trials (RCTs) published before November 2021 comparing early pharmacologic cardioversion and non-early cardioversion in recent-onset atrial fibrillation and synthesized data in accordance with PRISMA-Systematic Reviews and Network Meta-Analysis (NMA). Early pharmacological cardioversion referred to immediate cardioversion with antiarrhythmic drugs (i.e., amiodarone, propafenone, flecainide, tedisamil, vernakalant, vanoxerine, and sotalol) upon admission, while non-early cardioversion involved the administration of rate-control or placebo medication without immediate cardioversion.

Results

16 RCTs with 2,395 patients were included. Compared to non-early cardioversion, a systematic review showed that early pharmacologic cardioversion resulted in a higher probability of sinus rhythm maintenance within 24 h (odds ratios [OR] 2.50, 95% credible interval [CrI] 1.76 to 3.54) and 1-week (2.50, 1.76 to 3.54), however, there was no significant difference in sinus rhythm maintenance within 4-weeks (1.37, 0.90 to 2.09). In subgroup analysis, the Bayesian NMA revealed that vernakalant may be successful in sinus rhythm maintenance within both 24 h (3.55, 2.28 to 5.55) and 1-week (2.72, 1.72 to 4.31). The results were consistent with the frequentist NMA.

Conclusions

Non-early pharmacologic cardioversion may not be inferior to early cardioversion within a 4-week follow-up period in patients with recent-onset atrial fibrillation. The evidence remains insufficient to determine which antiarrhythmic agent is optimal in the longer run. Further high-quality relevant RCTs are necessary.

Clinical Trial Registration

PROSPERO CRD42020166862.

Investigational Anti-Atrial Fibrillation Pharmacology and Mechanisms by Which Antiarrhythmics Terminate the Arrhythmia: Where Are We in 2020?

Antiarrhythmic drugs remain the mainstay therapy for patients with atrial fibrillation (AF). A major disadvantage of the currently available anti-AF agents is the risk of induction of ventricular proarrhythmias. Aiming to reduce this risk, several atrial-specific or -selective ion channel block approaches have been introduced for AF suppression, but only the atrial-selective inhibition of the sodium channel has been demonstrated to be valid in both experimental and clinical studies. Among the other pharmacological anti-AF approaches, “upstream therapy” has been prominent but largely disappointing, and pulmonary delivery of anti-AF drugs seems to be promising. Major contradictions exist in the literature about the electrophysiological mechanisms of AF (ie, reentry or focal?) and the mechanisms by which anti-AF drugs terminate AF, making the search for novel anti-AF approaches largely empirical. Drug-induced termination of AF may or may not be associated with prolongation of the atrial effective refractory period. Anti-AF drug research has been largely based on the “suppress reentry” ideology; however, results of the AF mapping studies increasingly indicate that nonreentrant mechanism(s) plays an important role in the maintenance of AF. Also, the analysis of anti-AF drug-induced electrophysiological alterations during AF, conducted in the current study, leans toward the focal source as the prime mechanism of AF maintenance. More effort should be placed on the investigation of pharmacological suppression of the focal mechanisms.

Pharmacologic Cardioversion in Patients with Paroxysmal Atrial Fibrillation: A Network Meta-Analysis

PURPOSE

We sought to indirectly compare and rank antiarrhythmic agents focusing exclusively on adults with paroxysmal atrial fibrillation in order to identify the most effective for pharmacologic cardioversion over different time settings (4 h as primary, and 12, 24 h as secondary outcomes).

METHODS

We searched several databases from inception to March 2020 without language restrictions, ClinicalTrials.gov, references of reviews, and meeting abstract material. We included randomized controlled trials of patients with AF lasting ≤7 days comparing either two or more intravenous (i.v.) or oral (p.o.) pharmacologic cardioversion agents or an agent against placebo. For each outcome, we performed network meta-analysis based on the frequentist approach.

RESULTS

Forty-one trials (6013 patients) were included in our systematic review. Moderate confidence evidence suggests that i.v. vernakalant and flecainide have the highest conversion rate within 4 h, possibly allowing discharge from the emergency department and reducing hospital admissions. Intravenous and p.o. formulations of class IC antiarrhythmics (flecainide more so than propafenone) are superior regarding conversion rates within 12 h, while amiodarone efficacy is exhibited in a delayed fashion (within 24 h), especially if ranolazine is added.

CONCLUSION

Our network meta-analysis identified with sufficient power and consistency the most effective antiarrhythmics for pharmacologic cardioversion over different time settings, with vernakalant and flecainide exhibiting a safer and more efficacious profile toward faster cardioversion.

New methodological approaches to atrial fibrillation drug discovery

INTRODUCTION

Atrial fibrillation (AF) is the most common arrhythmia encountered in clinical practice and rhythm control using pharmacological agents is required in selected patients. Nonetheless, current medication is only modestly efficacious and associated with significant cardiovascular and systemic side effects. More efficacious and safe drugs are required to restore and maintain sinus rhythm in patients with AF.

AREAS COVERED

In this review, several potential drug targets are discussed including trans-membrane ion channels, intracellular calcium signaling, gap junction signaling, atrial inflammation and fibrosis, and the autonomic nervous system. New tools and methodologies for AF drug development are also reviewed including gene therapy, genome-guided therapy, stem cell technologies, tissue engineering, and optogenetics.

EXPERT OPINION

In recent decades, there has been an increased understanding of the underlying pathogenesis of AF. As a result, there is a gradual paradigm shift from focusing only on trans-membrane ion channel inhibition to developing therapeutic agents that target other underlying arrhythmogenic mechanisms. Gene therapy and genome-guided therapy are emerging as novel treatments for AF with some success in proof-of-concept studies. Recent advances in stem cell technology, tissue engineering, and optogenetics may allow more effective in-vitro drug screening than conventional methodologies.

The efficacy and safety of amiodarone combined with beta-blockers in the maintenance of sinus rhythm for atrial fibrillation: A protocol for systematic review and network meta-analysis

BACKGROUND

The high recurrence rate of atrial fibrillation (AF) after recovering sinus rhythm has always been a clinical problem. Despite the established and widespread use of antiarrhythmic drugs, which one is better for maintaining sinus rhythm is still controversial. This study aims to summarize the randomized controlled trials (RCTs) of amiodarone combined with beta blockers to maintain sinus rhythm in AF, and to determine an effective and safe intervention for the prevention of AF recurrence through network meta-analysis (NMA).

METHODS AND ANALYSIS

A comprehensive search of the RCTs comparing amiodarone with different beta-blockers to maintain sinus rhythm of AF patients will be conducted from the inception to December 2019 in the Cochrane Library, PubMed, Web of Science, EMBASE, Chinese Biomedical Literature Database (SinoMed), Chinese National Knowledge Infrastructure (CNKI), and WanFang database. The primary outcomes will be the recurrence of AF and frequency of embolization complications. The secondary outcomes will be the symptom improvements and adverse events. Risk of bias assessment of the included RCTs will be conducted according to the Cochrane collaboration's risk of bias tool. Pairwise meta-analyses and Bayesian network meta-analyses will be performed for all related outcome measures. GRADE will be used to evaluate the quality of evidence.

RESULTS

The results of this NMA will be published in a peer-reviewed journal.

CONCLUSION

This NMA may provide more recommendations for patients and researchers, such as which treatment is better for a particular case of AF, and what may be the hotspots for the future studies.

PROSPERO REGISTRATION NUMBER

The protocol for this NMA has been registered on PROSPERO under the number CRD42020164438.