Conversion efficacy of intravenous ibutilide compared with intravenous amiodarone in patients with recent-onset atrial fibrillation and atrial flutter

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.

Gender Differences With Ibutilide Effectiveness and Safety in Cardioversion of Atrial Fibrillation

INTRODUCTION

Few studies have examined the use of ibutilide in noncardiac surgical populations. Our study considered the effectiveness and safety of ibutilide in cardioversion of atrial fibrillation (AF) in medical and surgical intensive care patients.

METHODS

A retrospective chart review was performed for patients with a confirmed diagnosis of AF who were hemodynamically stable and received ibutilide after the initial diagnosis. Patients were administered 1 mg of ibutilide fumarate intravenous for 10 min with a second dose administered if AF persisted after 30 min. Patients were pretreated with intravenous magnesium sulfate if their blood magnesium level was <2 mg/dL.

RESULTS

Fifty seven total female patients and 99 male patients received ibutilide. Females had an 88% conversion rate to normal sinus rhythm (NSR) compared to 68% in males (P = 0.008). A 70% successful return to NSR was observed in patients from all groups pretreated with magnesium sulfate (P = 0.045). One year after discharge, 74% of the patients stayed in the NSR.

CONCLUSIONS

Within our population, pretreatment with magnesium sulfate followed by ibutilide was associated with increased conversion to NSR. Additionally, we noted that females had a higher conversion rate to NSR compared to males, regardless of whether they were pretreated with magnesium sulfate.

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.

Pathophysiology and treatment of adults with arrhythmias in the emergency department, part 2: Ventricular and bradyarrhythmias

PURPOSE

This is the second article in a 2-part series reviewing the pathophysiology and treatment considerations for arrhythmias. Part 1 of the series discussed aspects related to treating atrial arrhythmias. Here in part 2, the pathophysiology of ventricular arrhythmias and bradyarrhythmias and current evidence on treatment approaches are reviewed.

SUMMARY

Ventricular arrhythmias can arise suddenly and are a common cause of sudden cardiac death. Several antiarrhythmics may be effective in management of ventricular arrhythmias, but there is robust evidence to support the use of only a few of these agents, and such evidence was largely derived from trials involving patients with out-of-hospital cardiac arrest. Bradyarrhythmias range from asymptomatic mild prolongation of nodal conduction to severe conduction delays and impending cardiac arrest. Vasopressors, chronotropes, and pacing strategies require careful attention and titration to minimize adverse effects and patient harm.

CONCLUSION

Ventricular arrhythmias and bradyarrhythmias can be consequential and require acute intervention. As experts in pharmacotherapy, acute care pharmacists can participate in providing high-level intervention by aiding in diagnostic workup and medication selection.

Pathophysiology and treatment of adults with arrhythmias in the emergency department, part 1: Atrial arrhythmias

PURPOSE

This article, the first in a 2-part review, aims to reinforce current literature on the pathophysiology of cardiac arrhythmias and various evidence-based treatment approaches and clinical considerations in the acute care setting. Part 1 of this series focuses on atrial arrhythmias.

SUMMARY

Arrhythmias are prevalent throughout the world and a common presenting condition in the emergency department (ED) setting. Atrial fibrillation (AF) is the most common arrhythmia worldwide and expected to increase in prevalence. Treatment approaches have evolved over time with advances in catheter-directed ablation. Based on historic trials, heart rate control has been the long-standing accepted outpatient treatment modality for AF, but the use of antiarrhythmics is often still indicated for AF in the acute setting, and ED pharmacists should be prepared and poised to help in AF management. Other atrial arrhythmias include atrial flutter (AFL), atrioventricular nodal reentry tachycardia (AVNRT), and atrioventricular reentrant tachycardia (AVRT), which warrant distinction due to their unique pathophysiology and because each requires a different approach to utilization of antiarrhythmics. Atrial arrhythmias are typically associated with greater hemodynamic stability than ventricular arrhythmias but still require nuanced management according to patient subset and risk factors. Since antiarrhythmics can also be proarrhythmic, they may destabilize the patient due to adverse effects, many of which are the focus of black-box label warnings that can be overreaching and limit treatment options. Electrical cardioversion for atrial arrhythmias is generally successful and, depending on the setting and/or hemodynamics, often indicated.

CONCLUSION

Atrial arrhythmias arise from a variety of mechanisms, and appropriate treatment depends on various factors. A firm understanding of physiological and pharmacological concepts serves as a foundation for exploring evidence supporting agents, indications, and adverse effects in order to provide appropriate care for patients.

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 ).

Atrial Fibrillation Occurring During Acute Hospitalization: A Scientific Statement From the American Heart Association

Acute atrial fibrillation is defined as atrial fibrillation detected in the setting of acute care or acute illness; atrial fibrillation may be detected or managed for the first time during acute hospitalization for another condition. Atrial fibrillation after cardiothoracic surgery is a distinct type of acute atrial fibrillation. Acute atrial fibrillation is associated with high risk of long-term atrial fibrillation recurrence, warranting clinical attention during acute hospitalization and over long-term follow-up. A framework of substrates and triggers can be useful for evaluating and managing acute atrial fibrillation. Acute management requires a multipronged approach with interdisciplinary care collaboration, tailoring treatments to the patient's underlying substrate and acute condition. Key components of acute management include identification and treatment of triggers, selection and implementation of rate/rhythm control, and management of anticoagulation. Acute rate or rhythm control strategy should be individualized with consideration of the patient's capacity to tolerate rapid rates or atrioventricular dyssynchrony, and the patient's ability to tolerate the risk of the therapeutic strategy. Given the high risks of atrial fibrillation recurrence in patients with acute atrial fibrillation, clinical follow-up and heart rhythm monitoring are warranted. Long-term management is guided by patient substrate, with implications for intensity of heart rhythm monitoring, anticoagulation, and considerations for rhythm management strategies. Overall management of acute atrial fibrillation addresses substrates and triggers. The 3As of acute management are acute triggers, atrial fibrillation rate/rhythm management, and anticoagulation. The 2As and 2Ms of long-term management include monitoring of heart rhythm and modification of lifestyle and risk factors, in addition to considerations for atrial fibrillation rate/rhythm management and anticoagulation. Several gaps in knowledge related to acute atrial fibrillation exist and warrant future research.

Antiarrhythmic Drug Therapy in the Treatment of Acute and Chronic Atrial Flutter

In the present article, we will focus on the pharmacologic treatment of atrial flutter aimed either at restoring/maintaining sinus rhythm or controlling the ventricular response during tachyarrhythmia. To provide a comprehensive description we will start discussing the electroanatomic substrate underlying the development of atrial flutter and the complex relationship with atrial fibrillation. We will then describe the available drugs for the treatment of atrial flutter on the bases of their electrophysiological effects and data from available clinical studies. We will conclude by discussing the general principles of rhythm and rate control treatment during atrial flutter.

Cardioversion of Post-Ablation Atrial Tachyarrhythmia with Ibutilide and Amiodarone: A Registry-Based Cohort Study

Patients with recurrence of atrial tachyarrhythmia after catheter ablation for atrial fibrillation or atrial flutter constitute a rapidly growing cohort, but study-driven treatment recommendations are lacking. The present study aimed to compare the cardioversion success of ibutilide and amiodarone in patients with post-ablation atrial tachyarrhythmia. We included all episodes of post-ablation atrial tachyarrhythmia in patients treated with either intravenous ibutilide or amiodarone at an academic emergency department from 2010 to 2018. The primary endpoint was the conversion to sinus rhythm. The conversion rates were stratified by arrhythmia type, and multivariable cluster-adjusted logistic regression was used to estimate the effect of ibutilide and amiodarone on cardioversion success, given as the odds ratio (OR) with 95% confidence intervals (95% CI). In total, 109 episodes of 72 patients were analyzed. The conversion rates were 37/49 (76%) for ibutilide and 16/60 (27%) for amiodarone. Compared to amiodarone, ibutilide was associated with higher odds of conversion (multivariable cluster-adjusted OR 5.6, 95% CI 1.3–24.3). The cardioversion success of ibutilide was the highest in atrial flutter (crude OR 19.5, 95% CI 3.4–112.5) and focal atrial tachycardia (crude OR 8.3, 95% CI 1.5–47.2), but it was less pronounced in atrial fibrillation (crude OR 4.5, 95% CI 1.2–17.2). Randomized trials are warranted to confirm our findings.

Prediction of Successful Pharmacological Cardioversion in Acute Symptomatic Atrial Fibrillation: The Successful Intravenous Cardioversion for Atrial Fibrillation (SIC-AF) Score

Background: Modern personalised medicine requires patient-tailored decisions. This is particularly important when considering pharmacological cardioversion for the acute treatment of haemodynamically stable atrial fibrillation and atrial flutter in a shared decision-making process. We aimed to develop and validate a predictive model to estimate the individual probability of successful pharmacological cardioversion using different intravenous antiarrhythmic agents. Methods: We analysed data from a prospective atrial fibrillation registry comprising 3053 cases of first-detected or recurrent haemodynamically stable, non-permanent, symptomatic atrial fibrillation presenting to an Austrian academic emergency department between January 2012 and December 2017. Using multivariable analysis, a prediction score was developed and externally validated. The clinical utility of the score was assessed using decision curve analysis. Results: A total of 1528 cases were included in the development cohort (median age 69 years, IQR 58−76; 43.9% female), and 1525 cases were included in the validation cohort (median age 68 years, IQR (58−75); 39.5% female). Finally, 421 cases were available for score development and 330 cases for score validation The weighted score included atrial flutter (8 points), duration of symptoms associated with AF (<24 h; 8 points), absence of previous electrical cardioversion (10 points), and the specific intravenous antiarrhythmic drug (amiodarone 10 points, vernakalant 11 points, ibutilide 13 points). The final score, the “Successful Intravenous Cardioversion for Atrial Fibrillation (SIC-AF) score,” showed good calibration (R2 = 0.955 and R2 = 0.954) and discrimination in both sets (c-indices: 0.68 and 0.66) and net clinical benefit. Conclusions: A predictive model was developed to estimate the success of intravenous pharmacological cardioversion using different antiarrhythmic agents in a cohort of patients with haemodynamically stable, non-permanent, symptomatic atrial fibrillation. External temporal validation confirmed good calibration, discrimination, and clinical usefulness. The SIC-AF score may help patients and physicians jointly decide on the appropriate treatment strategy for acute symptomatic atrial fibrillation. Registration: NCT03272620.

Safety and Efficacy of Ibutilide for Acute Pharmacological Cardioversion of Rheumatic Atrial Fibrillation

INTRODUCTION

Ibutilide is indicated for acute cardioversion of nonvalvular atrial fibrillation (AF). However, its efficacy and safety in the pharmacological cardioversion of rheumatic AF are unknown.

METHODS

Patients with mild-to-moderate rheumatic mitral valve (MV) disease with symptomatic, paroxysmal, or persistent AF were included in the analysis. Intravenous ibutilide was administered at doses tailored to body weight (0.5-2.0 mg) for over 10 min. The primary end point was efficacy, assessed as the rate of conversion of AF to sinus rhythm. The secondary end point was safety, including arrhythmic events and death within 24 h of drug initiation.

RESULTS

From June 2016 to October 2018, 165 patients (94 with mitral stenosis, 23 with mitral regurgitation, 11 with mixed MV disease, and 37 with MV replacement) received ibutilide (mean dose 0.90 ± 0.54 mg). Ibutilide successfully converted AF to sinus rhythm in 127/165 (76.9%) patients, with a conversion time of 7.9 ± 4.1 min. The QTc increased from 419.9 ± 15.8 to 487.5 ± 34 ms after ibutilide administration (p < 0.001). The mean change in QTc after ibutilide administration (∆QTc) was 72.01 ± 36.03. There were no deaths, but 3 patients (1.8%) developed torsades de pointes (TdP) requiring defibrillation 55 ± 37 min after infusion.

CONCLUSION

Ibutilide cardioverted 77% of rheumatic AF to sinus rhythm, indicating its potential as a clinically useful option for pharmacological cardioversion of rheumatic AF. TdP is a potentially serious adverse event that requires careful monitoring.

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

AIMS

We sought to identify the most effective antidysrhythmic drug for pharmacologic cardioversion of recent-onset atrial fibrillation (AF).

METHODS AND RESULTS

We searched MEDLINE, Embase, and Web of Science from inception to March 2019, limited to human subjects and English language. We also searched for unpublished data. We limited studies to randomized controlled trials that enrolled adult patients with AF ≤ 48 h and compared antidysrhythmic agents, placebo, or control. We determined these outcomes prior to data extraction: (i) rate of conversion to sinus rhythm within 24 h, (ii) time to cardioversion to sinus rhythm, (iii) rate of significant adverse events, and (iv) rate of thromboembolism within 30 days. We extracted data according to PRISMA-NMA and appraised selected trials using the Cochrane review handbook. The systematic review initially identified 640 studies; 30 met inclusion criteria. Twenty-one trials that randomized 2785 patients provided efficacy data for the conversion rate outcome. Bayesian network meta-analysis using a random-effects model demonstrated that ranolazine + amiodarone intravenous (IV) [odds ratio (OR) 39.8, 95% credible interval (CrI) 8.3-203.1], vernakalant (OR 22.9, 95% CrI 3.7-146.3), flecainide (OR 16.9, 95% CrI 4.1-73.3), amiodarone oral (OR 10.2, 95% CrI 3.1-36.0), ibutilide (OR 7.9, 95% CrI 1.2-52.5), amiodarone IV (OR 5.4, 95% CrI 2.1-14.6), and propafenone (OR 4.1, 95% CrI 1.7-10.5) were associated with significantly increased likelihood of conversion within 24 h when compared to placebo/control. Overall quality was low, and the network exhibited inconsistency. Probabilistic analysis ranked vernakalant and flecainide high and propafenone and amiodarone IV low.

CONCLUSION

For pharmacologic cardioversion of recent-onset AF within 24 h, there is insufficient evidence to determine which treatment is superior. Vernakalant and flecainide may be relatively more efficacious agents. Propafenone and IV amiodarone may be relatively less efficacious. Further high-quality study is necessary.

Current Drug Treatment Strategies for Atrial Fibrillation and TASK-1 Inhibition as an Emerging Novel Therapy Option

Atrial fibrillation (AF) is the most common sustained arrhythmia with a prevalence of up to 4% and an upwards trend due to demographic changes. It is associated with an increase in mortality and stroke incidences. While stroke risk can be significantly reduced through anticoagulant therapy, adequate treatment of other AF related symptoms remains an unmet medical need in many cases. Two main treatment strategies are available: rate control that modulates ventricular heart rate and prevents tachymyopathy as well as rhythm control that aims to restore and sustain sinus rhythm. Rate control can be achieved through drugs or ablation of the atrioventricular node, rendering the patient pacemaker-dependent. For rhythm control electrical cardioversion and pharmacological cardioversion can be used. While electrical cardioversion requires fasting and sedation of the patient, antiarrhythmic drugs have other limitations. Most antiarrhythmic drugs carry a risk for pro-arrhythmic effects and are contraindicated in patients with structural heart diseases. Furthermore, catheter ablation of pulmonary veins can be performed with its risk of intraprocedural complications and varying success. In recent years TASK-1 has been introduced as a new target for AF therapy. Upregulation of TASK-1 in AF patients contributes to prolongation of the action potential duration. In a porcine model of AF, TASK-1 inhibition by gene therapy or pharmacological compounds induced cardioversion to sinus rhythm. The DOxapram Conversion TO Sinus rhythm (DOCTOS)-Trial will reveal whether doxapram, a potent TASK-1 inhibitor, can be used for acute cardioversion of persistent and paroxysmal AF in patients, potentially leading to a new treatment option for AF.

A randomized, controlled comparison of electrical versus pharmacological cardioversion for emergency department patients with acute atrial flutter

BACKGROUND

Acute atrial flutter has one-tenth the prevalence of acute atrial fibrillation in the emergency department (ED) but shares many management strategies. Our aim was to compare conversion from acute atrial flutter to sinus rhythm between pharmacological cardioversion followed by electrical cardioversion (Drug-Shock), and electrical cardioversion alone (Shock-Only).

METHODS

We conducted a randomized, blinded, placebo-controlled comparison of attempted pharmacological cardioversion with IV procainamide followed by electrical cardioversion if necessary, and placebo infusion followed by electrical cardioversion. We enrolled stable patients with a primary diagnosis of acute acute atrial flutter at 11 academic EDs. The primary outcome was conversion to normal sinus rhythm.

FINDINGS

From July 2013 to October 2018, we enrolled 76 patients, and none were lost to follow-up. Comparing the Drug-Shock to the Shock-Only group, conversion to sinus rhythm occurred in 33 (100%) versus 40 (93%) (absolute difference 7.0%; 95% CI - 0.6 to 14.6; P = 0.25). Median time to conversion from start of infusion in the Drug-Shock group was 24 min (IQR 21-82) but only 9 (27%) cases were converted with IV procainamide. Patients in both groups had similar outcomes at 14 days; there were no strokes or deaths.

INTERPRETATION

This trial found that the Drug-Shock strategy is potentially superior but that either approach to immediate rhythm control in the ED for patients with acute acute atrial flutter is highly effective, rapid, and safe in restoring sinus rhythm and allowing patients to go home and return to normal activities. Unlike the case of atrial fibrillation, we found that IV procainamide alone was infrequently effective.

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.

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

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

Pharmacologic Cardioversion of Recent-Onset Atrial Fibrillation and Flutter in the Emergency Department: A Systematic Review and Network Meta-analysis

STUDY OBJECTIVE

We conduct a systematic review and Bayesian network meta-analysis to indirectly compare and rank antidysrhythmic drugs for pharmacologic cardioversion of recent-onset atrial fibrillation and atrial flutter in the emergency department (ED).

METHODS

We searched MEDLINE, EMBASE, and Web of Science from inception to March 2019, limited to human subjects and English language. We also searched for unpublished data. We limited studies to randomized controlled trials that enrolled adult patients with recent-onset atrial fibrillation or atrial flutter and compared antidysrhythmic agents, placebo, or control. We determined these outcomes before data extraction: rate of conversion to sinus rhythm within 4 hours, time to cardioversion, rate of significant adverse events, and rate of thromboembolism within 30 days. We extracted data according to Preferred Reporting Items for Systematic Reviews and Meta-analyses network meta-analysis and appraised selected trials with the Cochrane review handbook.

RESULTS

The systematic review initially identified 640 studies; 19 met inclusion criteria. Eighteen trials that randomized 2,069 atrial fibrillation patients provided data for atrial fibrillation conversion rate outcome. Bayesian network meta-analysis using a random-effects model demonstrated that antazoline (odds ratio [OR] 24.9; 95% credible interval [CrI] 7.4 to 107.8), tedisamil (OR 12.0; 95% CrI 4.3 to 43.8), vernakalant (OR 7.5; 95% CrI 3.1 to 18.6), propafenone (OR 6.8; 95% CrI 3.6 to 13.8), flecainide (OR 6.1; 95% CrI 2.9 to 13.2), and ibutilide (OR 4.1; 95% CrI 1.8 to 9.6) were associated with increased likelihood of conversion within 4 hours compared with placebo or control. Overall quality was low, and the network exhibited inconsistency.

CONCLUSION

For pharmacologic cardioversion of recent-onset atrial fibrillation within a 4-hour ED visit, there is insufficient evidence to determine which treatment is superior. Several agents are associated with increased likelihood of conversion within 4 hours compared with placebo or control. Limited data preclude any recommendation for cardioversion of recent-onset atrial flutter. Further high-quality study is necessary.

Ibutilide Effectiveness and Safety in the Cardioversion of Atrial Fibrillation and Flutter in the Community Emergency Department

STUDY OBJECTIVE

Little is known about the use of ibutilide for cardioversion in atrial fibrillation and flutter outside of clinical trials. We seek to describe patient characteristics, ibutilide administration patterns, cardioversion rates, and adverse outcomes in the community emergency department (ED) setting. We also evaluate potential predictors of cardioversion success.

METHODS

Using a retrospective cohort of adults who received ibutilide in 21 community EDs between January 2009 and June 2015, we gathered demographic and clinical variables from electronic health records and structured manual chart review. We calculated rates of cardioversion and frequency of ventricular tachycardia within 4 hours and estimated adjusted odds ratios (aOR) in a multivariate regression model for potential predictors of cardioversion.

RESULTS

Among 361 patients, the median age was 61 years (interquartile range 53 to 71 years) and most had recent-onset atrial fibrillation and flutter (98.1%). Five percent of the cohort had a history of heart failure. The initial QTc interval was prolonged (>480 ms) in 29.4% of patients, and 3.1% were hypokalemic (<3.5 mEq/L). The mean ibutilide dose was 1.5 mg (SD 0.5 mg) and the rate of ibutilide-related cardioversion within 4 hours was 54.8% (95% confidence interval [CI] 49.6% to 60.1%), 50.5% for atrial fibrillation and 75.0% for atrial flutter. Two patients experienced ventricular tachycardia (0.6%), both during their second ibutilide infusion. Age (in decades) (aOR 1.3; 95% CI 1.1 to 1.5), atrial flutter (versus atrial fibrillation) (aOR 2.7; 95% CI 1.4 to 5.1), and no history of atrial fibrillation and flutter (aOR 2.0; 95% CI 1.2 to 3.1) were associated with cardioversion.

CONCLUSION

The effectiveness and safety of ibutilide in this community ED setting were consistent with clinical trial results despite less stringent patient selection criteria.

Pretreatment with intravenous amiodarone improves the efficacy of ibutilide treatment on cardioversion rate and maintenance time of sinus rhythm in patients with persistent atrial fibrillation

The aim of the present study was to assess the efficacy and safety of the pharmacological conversion of persistent atrial fibrillation (AF) using amiodarone or/and ibutilide. Seventy-nine consecutive patients (48 males and 31 females; mean age, 64.6±11.2 years; range, 40-80 years) with non-valvular chronic AF lasting >7 days (range, 7-97 days) that were admitted to hospital for elective pharmacological cardioversion were randomly assigned to receive treatment with intravenous ibutilide (1 mg plus an additional 1 mg if required; n=39) or intravenous amiodarone (300 mg) plus intravenous ibutilide (1 mg; n=40). Success rates of cardioversion were 51.3% (20/39 patients) for ibutilide alone and 71.8% (28/39 patients) for amiodarone + ibutilide (P<0.05). A comparable increase in the QTc interval was observed in the two groups. It was observed that the co-administration of amiodarone and ibutilide was safer than ibutilide alone with regard to the risk of ventricular arrhythmia. Forty-eight patients of successful cardioversion were personally contacted for follow-up. The result indicated that the sinus rhythm maintenance time of the amiodarone + ibutilide group (4.36±2.44 months) was significantly higher than that of the ibutilide group (2.34±1.75 months; P<0.01). In conclusion, pretreatment with intravenous amiodarone + ibutilide for pharmacological cardioversion of persistent AF is considered to be more effective and safer than treatment with ibutilide alone.

Atrial Flutter, Typical and Atypical: A Review

Clinical electrophysiology has made the traditional classification of rapid atrial rhythms into flutter and tachycardia of little clinical use. Electrophysiological studies have defined multiple mechanisms of tachycardia, both re-entrant and focal, with varying ECG morphologies and rates, authenticated by the results of catheter ablation of the focal triggers or critical isthmuses of re-entry circuits. In patients without a history of heart disease, cardiac surgery or catheter ablation, typical flutter ECG remains predictive of a right atrial re-entry circuit dependent on the inferior vena cava-tricuspid isthmus that can be very effectively treated by ablation, although late incidence of atrial fibrillation remains a problem. Secondary prevention, based on the treatment of associated atrial fibrillation risk factors, is emerging as a therapeutic option. In patients subjected to cardiac surgery or catheter ablation for the treatment of atrial fibrillation or showing atypical ECG patterns, macro-re-entrant and focal tachycardia mechanisms can be very complex and electrophysiological studies are necessary to guide ablation treatment in poorly tolerated cases.

Executive Summary: European Heart Rhythm Association Consensus Document on the Management of Supraventricular Arrhythmias: Endorsed by Heart Rhythm Society (HRS), Asia-Pacific Heart Rhythm Society (APHRS), and Sociedad Latinoamericana de Estimulación Cardiaca y Electrofisiologia (SOLAECE)

This paper is an executive summary of the full European Heart Rhythm Association (EHRA) consensus document on the management of supraventricular arrhythmias, published in Europace. It summarises developments in the field and provides recommendations for patient management, with particular emphasis on new advances since the previous European Society of Cardiology guidelines. The EHRA consensus document is available to read in full at http://europace.oxfordjournals.org.

[Rate and rhythm control in atrial fibrillation : pharmacological approaches]

Atrial fibrillation is the most common form of cardiac arrhythmia, occurring in 1-2 % of the population and due to an increased life expectancy the prevalence will increase further. Pharmacological treatment of atrial fibrillation is an important component of basic initial therapeutic options for patients with atrial fibrillation. Independent of an individually adjusted prevention of thromboembolism, rate and rhythm management can also be carried out. While rate control mainly applies to all patients, rhythm control is only indicated in patients who remain clinically symptomatic despite sufficient rate control. Profound knowledge about antiarrhythmic drugs including specific interactions is necessary due to the variable individual effects and sometimes severe side effects.

Anti-Arrhythmic Agents in the Treatment of Atrial Fibrillation

Although atrial fibrillation (AF) is the most common sustained arrhythmia seen during daily cardiovascular physician practice, its management remained a challenge for cardiology physician as there was no single anti-arrhythmic agents proved to be effective in converting atrial fibrillation and kept its effectiveness in maintaining sinus rhythm over long term. Moreover all the anti-arrhythmic agents that are used in treatment of AF were potentially pro-arrhythmic especially in patients with coronary artery disease and structurally abnormal heart. Some of these drugs also have serious non cardiac side effects that limit its long term use in the management of atrial fibrillation. Several new and investigational anti-arrhythmic agents are emerging but data supporting their effectiveness and safety are still limited. In this systematic review we examine the efficacy and safety of these medications supported by the major published randomized trials, meta-analyses and review articles and conclude with a summary of guidelines recommendations.

Management strategies in atrial fibrillation in patients with heart failure

Atrial fibrillation (AF) and heart failure (HF) frequently occur together, and their coexistence is associated with a poor prognosis. AF and HF share risk factors, but their relationship involves complex hemodynamic, neurohormonal, inflammatory, ultrastructural, and electrophysiologic processes that extend beyond epidemiological associations. The shared mechanisms underlying AF and HF have important implications for the treatment of AF in patients with HF. This article focuses on reviewing contemporary data as it pertains to AF management in patients with HF and provides insight into investigational therapies currently under development.

Safety and efficiency of calcium channel blockers versus beta-blockers for rate control in patients with atrial fibrillation and no acute underlying medical illness

OBJECTIVES

Many patients with atrial fibrillation (AF) are not candidates for rhythm control and may require rate control, typically with beta-blocking (BB) or calcium channel blocking (CCB) agents. Although these patients appear to have a low 30-day rate of stroke or death, it is unclear if one class of agent is safer or more effective. The objective was to determine whether BBs or CCBs would have a lower hospital admission rate and to measure 30-day safety outcomes including stroke, death, and emergency department (ED) revisits.

METHODS

This retrospective cohort study used a database from two urban EDs to identify consecutive patients with ED discharge diagnoses of AF from April 1, 2006, to March 31, 2010. Comorbidities, rhythms, management, and immediate outcomes were obtained by manual chart review, and patients with acute underlying medical conditions were excluded by predefined criteria. Patients managed only with rate control agents were eligible for review, and patients receiving BB agents were compared to those receiving CCB agents. The primary outcome was the proportion of patients requiring hospital admission; secondary outcomes included the ED length of stay (LOS), the proportion of patients having adverse events, the proportion of patients returning within 7 or 30 days, and the number of patients having a stroke or dying within 30 days.

RESULTS

A total of 259 consecutive patients were enrolled, with 100 receiving CCBs and 159 receiving BBs. Baseline demographics and comorbidities were similar. Twenty-seven percent of BB patients were admitted, and 31.0% of CCB patients were admitted (difference = 4.0%, 95% confidence interval [CI] = -7.7% to 16.1%), and there were no significant differences in ED LOS, adverse events, or 7- or 30-day ED revisits. One patient who received metoprolol had a stroke, and one patient who received diltiazem died within 30 days.

CONCLUSIONS

In this cohort of ED patients with AF and no acute underlying medical illness who underwent rate control only, patients receiving CCBs had similar hospital admission rates to those receiving BBs, while both classes of medications appeared equally safe at 30 days. Both CCBs and BBs are acceptable options for rate control.

Antiarrhythmic drugs for atrial fibrillation

INTRODUCTION

Atrial fibrillation (AF) is associated with increased mortality and morbidity. Although stroke prevention is the only way to improve prognosis, antiarrhythmic drugs (AADs) are of primary importance both in the conversion to sinus rhythm and in the long-term control of rhythm and rate.

AREAS COVERED

We searched the Cochrane Library and Medline Database for articles published in English concerning efficacy and safety of AADs in AF. Particular attention was paid to the recently published European Society of Cardiology guidelines. This review provides an overview of the currently available drugs used in AF, with a particular emphasis on their comparative efficacy and safety in different kind of patients. Recent important findings, and advantages and disadvantages of recently approved drugs such as vernakalant and dronedarone, are also discussed.

EXPERT OPINION

AADs remain fundamental in the acute and long-term management of AF, to control symptoms and to reduce the negative impact of the arrhythmia on QoL. The choice of a rate- over rhythm-control strategy should be individualized and based on accurate evaluation of patient medical history and symptoms. New agents will contribute to improve treatment efficacy together with the guarantee of better safety profiles.

Pharmacologic Conversion of Atrial Fibrillation and Atrial Flutter

Atrial fibrillation and atrial flutter are common arrhythmias in everyday clinical settings. Pharmacologic cardioversion (CV) is a simple and widely used strategy for the treatment of these arrhythmias, and many drugs are currently available. The choice of drug is strongly influenced by the time elapsed from atrial fibrillation onset and by a patient's clinical subset. Electrical direct-current CV is the treatment of choice in long-lasting forms; nevertheless, some agents also show efficacy in this setting. In addition, promising results come from studies on the efficacy and safety of new antiarrhythmic drugs and from therapeutic approaches that reduce the need for hospitalization and improve quality of life.

Diagnosis and management of typical atrial flutter

Typical atrial flutter (AFL) is a common atrial arrhythmia that may cause significant symptoms and serious adverse effects including embolic stroke, myocardial ischemia and infarction, and rarely a tachycardia-induced cardiomyopathy as a result of rapid atrioventricular conduction. As a result of the well-defined anatomic and electrophysiological substrate, and the relative pharmacologic resistance of typical AFL, radiofrequency catheter ablation has emerged in the past decade as a safe and effective first-line treatment. This article reviews the electrophysiology of typical AFL and the techniques currently used for its diagnosis and management.

Diagnosis and management of typical atrial flutter

Can "past decade" be rephrased to refer to more specific years? Typical atrial flutter (AFL) is a common atrial arrhythmia that may cause significant symptoms and serious adverse effects, including embolic stroke, myocardial ischemia and infarction, and, rarely, a tachycardia-induced cardiomyopathy resulting from rapid atrioventricular conduction. As a result of the well-defined anatomic and electrophysiologic substrate and the relative pharmacologic resistance of typical AFL, radiofrequency catheter ablation has emerged since its first description in 1992 as a safe and effective first-line treatment. This article reviews the electrophysiology of typical AFL and techniques currently used for its diagnosis and management.

Biochemistry and biology of mammalian DNA methyltransferases

DNA methylation is a stable but not irreversible epigenetic signal that silences gene expression. It has a variety of important functions in mammals, including control of gene expression, cellular differentiation and development, preservation of chromosomal integrity, parental imprinting and X-chromosome inactivation. In addition, it has been implicated in brain function and the development of the immune system. Somatic alterations in genomic methylation patterns contribute to the etiology of human cancers and ageing. It is tightly interwoven with the modification of histone tails and other epigenetic signals. Here we review our current understanding of the molecular enzymology of the mammalian DNA methyltransferases Dnmt1, Dnmt3a, Dnmt3b and Dnmt2 and the roles of the enzymes in the above-mentioned biological processes.