Intravenous propafenone: efficacy and safety in the conversion to sinus rhythm of recent onset atrial fibrillation--a single-blind placebo-controlled study

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.

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.

Treatments of new-onset atrial fibrillation in critically ill patients: a systematic review with meta-analysis

BACKGROUND

New-onset atrial fibrillation (NOAF) is common in hospitalised patients with critical illness and associated with worse outcomes. Several interventions are available in the management of NOAF, but the overall effectiveness and safety of these interventions compared with placebo or no treatment are unknown.

METHODS

We conducted a systematic review with meta-analysis and trial sequential analysis (TSA) of randomised clinical trials (RCT) in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-analyses, the Cochrane Collaboration, and Grading of Recommendations Assessment, Development and Evaluation statements. We searched RCTs assessing any pharmacological and non-pharmacological treatment compared with placebo or no treatment in critically ill hospitalised patients with NOAF. The primary outcomes were all-cause mortality, adverse events, and health-related quality of life.

RESULTS

We included 16 trials (n = 1891) evaluating seven interventions. All trials were adjudicated 'some concerns' or 'high risk' of bias. The evidence is very uncertain for mortality (RR 0.53, 95% CI 0.03-8.30), adverse events (RR 1.28, 95% CI 0.85-1.92), and treatment efficacy i.e. rhythm control (RR 1.54, 95% CI 1.20-1.97; TSA-adjusted CI 0.56-4.53) between pharmacological treatment and placebo/no treatment (very low certainty evidence). There were no data for health-related quality of life or most of our secondary outcomes.

CONCLUSIONS

The existing data are insufficient to firmly conclude on effects of any intervention against NOAF on any outcome in hospitalised patients with critical illness. Randomised trials of the most frequently used interventions against NOAF are warranted in these patients.

Cardioversion of recent-onset atrial fibrillation using intravenous antiarrhythmics: A European perspective

Pharmacological cardioversion using intravenous antiarrhythmic agents is commonly indicated in symptomatic patients with recent-onset atrial fibrillation (AF). Except in hemodynamically unstable patients who require emergency direct current electrical cardioversion, for the majority of hemodynamically stable patients, pharmacological cardioversion represents a valid option and requires the clinician to be familiar with the properties and use of antiarrhythmic agents. The main characteristics of selected intravenous antiarrhythmic agents for conversion of recent-onset AF, the reported success rates, and possible adverse events are discussed. Among intravenous antiarrhythmics, flecainide, propafenone, amiodarone, sotalol, dofetilide, ibutilide, and vernakalant are commonly used. Antazoline, an old antihistaminic agent with antiarrhythmic properties was also reported to give encouraging results in Poland. Intravenous flecainide and propafenone are the only Class I agents still recommended by recent guidelines. Intravenous new Class III agents as dofetilide and ibutilide have high and rapid efficacy in converting AF to sinus rhythm but require strict surveillance with electrocardiogram (ECG) monitoring during and after intravenous administration because of the potential risk of QT prolongation and Torsades de Pointes, which can be prevented and properly managed. Vernakalant, a partial atrial selective was shown to have a high success rate and to be safe in real-life use.

Frequency and Determinants of Spontaneous Conversion to Sinus Rhythm in Patients Presenting to the Emergency Department with Recent-onset Atrial Fibrillation: A Systematic Review

The exact frequency and clinical determinants of spontaneous conversion (SCV) in patients with symptomatic recent-onset AF are unclear. The aim of this systematic review is to provide an overview of the frequency and determinants of SCV of AF in patients presenting at the emergency department. A comprehensive literature search for studies about SCV in patients presenting to the emergency department with AF resulted in 25 articles - 12 randomised controlled trials and 13 observational studies. SCV rates range between 9-83% and determinants of SCV also varied between studies. The most important determinants of SCV included short duration of AF (<24 or <48 hours), low number of episodes, normal atrial dimensions and absence of previous heart disease. The large variation in SCV rate and determinants of SCV was related to differences in duration of the observation period, inclusion and exclusion criteria and in variables used in the prediction models.

Systematic Review and Meta-analysis Appraising Efficacy and Safety of Vernakalant for Cardioversion of Recent-Onset Atrial Fibrillation

Vernakalant is a novel, relatively atrial-selective antiarrhythmic agent. Despite its good efficacy profile and rapid onset of action, there was still controversial evidence regarding vernakalant-related adverse events. We searched PubMed and Embase for studies that compared intravenous vernakalant with placebo or antiarrhythmic agents in patients with recent-onset atrial fibrillation (AF) lasting no more than 7 days. Efficacy and safety outcomes were the treatment-induced cardioversion rate within 90 minutes and adverse events after first exposure to study drug respectively. Nine randomized controlled trials enrolling 1296 patients were analyzed. Quantitative synthesis showed that vernakalant was superior to placebo for cardioversion of recent-onset AF within 90 minutes [49.7% vs. 6.2%, risk ratio (RR) 8.13, 95% confidence interval (CI) 5.35-12.36, P < 0.00001], and it did not achieve statistical significance in cardioversion when vernakalant was compared with ibutilide (62.4% vs. 47.3%, RR 1.32, 95% CI 1.00-1.73, P = 0.05). As for safety assessment, no significant differences were found in occurring serious adverse events (9.9% vs. 10.4%, RR 0.91, 95% CI 0.67-1.25, P = 0.57) and hypotension (5.3% vs. 3.3%, RR 1.53, 95% CI 0.86-2.73, P = 0.15) between vernakalant and comparator (either placebo, ibutilide, or amiodarone). There were trends that patients receiving vernakalant experienced more drug discontinuation (2.5% vs. 1.0%, RR 2.21, 95% CI 0.96-5.11, P = 0.06) and less any ventricular tachycardia (6.1% vs. 8.1%, RR 0.70, 95% CI 0.49-1.00, P = 0.05) than those receiving comparator, but the differences were not statistically significant. Furthermore, vernakalant was associated with a higher risk of bradycardia in comparison with comparator (6.3% vs. 1.1%, RR 4.04, 95% CI 1.67-9.75, P = 0.002). Vernakalant is effective in converting recent-onset AF to sinus rhythm rapidly, while significantly more bradycardia events are related to vernakalant in our meta-analysis.

A new antiarrhythmic drug in the treatment of recent-onset atrial fibrillation: vernakalant

Vernakalant is a new antiarrhythmic agent recently approved in Europe for the rapid cardioversion of recent-onset atrial fibrillation. It works by blocking early-activating K+ atrial channels and frequency-dependent atrial Na+ channels, prolonging atrial refractory periods and rate-dependent slowing atrial conduction, without promoting ventricular arrhythmia. Preclinical and clinical trials showed good toleration of this drug. The main purpose of our review is to describe all the trials that led to the incorporation of vernakalant into the current European atrial fibrillation guidelines.

Pharmacological conversion of recent-onset atrial fibrillation: a systematic review

OBJECTIVES

Recent-onset (duration ≤ 1 week) atrial fibrillation (AF) has a high rate of spontaneous conversion to sinus rhythm (SR); still anti-arrhythmic drugs (AAD) are given for conversion purposes. We assessed the effect of AADs by reviewing the literature regarding conversion rates of available drugs in a systematic manner.

DESIGN

PubMed searches were performed using the terms "drug name", "atrial fibrillation", and "clinical study/RCT", and a list of 1302 titles was generated. These titles, including abstracts or complete papers when needed, were reviewed for recent-onset of AF, the use of a control group, and the endpoint of SR within 24 hours. Postoperative and intensive care settings were excluded.

RESULTS

Five AADs were demonstrated to have an effect, and these were Amiodarone, Ibutilide (only one study and risk of torsade de pointes), Flecainide and Propafenone (only to be used in patients without structural heart disease) and Vernakalant. The time taken for conversion differed markedly; Vernakalant converted after 10 minutes, while Amiodarone converted only after 24 hours; Propafenone and Flecainide had conversion times in-between.

CONCLUSIONS

For a rapid response in a broad group of patients, Vernakalant appears to be a reasonable first choice, while Flecainide and Propafenone can be used in patients without structural heart disease.

A randomized active-controlled study comparing the efficacy and safety of vernakalant to amiodarone in recent-onset atrial fibrillation

OBJECTIVES

This randomized double-blind study compared the efficacy and safety of intravenous vernakalant and amiodarone for the acute conversion of recent-onset atrial fibrillation (AF).

BACKGROUND

Intravenous vernakalant has effectively converted recent-onset AF and was well tolerated in placebo-controlled studies.

METHODS

A total of 254 adult patients with AF (3 to 48 h duration) eligible for cardioversion were enrolled in the study. Patients received either a 10-min infusion of vernakalant (3 mg/kg) followed by a 15-min observation period and a second 10-min infusion (2 mg/kg) if still in AF, plus a sham amiodarone infusion, or a 60-min infusion of amiodarone (5 mg/kg) followed by a maintenance infusion (50 mg) over an additional 60 min, plus a sham vernakalant infusion.

RESULTS

Conversion from AF to sinus rhythm within the first 90 min (primary end point) was achieved in 60 of 116 (51.7%) vernakalant patients compared with 6 of 116 (5.2%) amiodarone patients (p < 0.0001). Vernakalant resulted in rapid conversion (median time of 11 min in responders) and was associated with a higher rate of symptom relief compared with amiodarone (53.4% of vernakalant patients reported no AF symptoms at 90 min compared with 32.8% of amiodarone patients; p = 0.0012). Serious adverse events or events leading to discontinuation of study drug were uncommon. There were no cases of torsades de pointes, ventricular fibrillation, or polymorphic or sustained ventricular tachycardia.

CONCLUSIONS

Vernakalant demonstrated efficacy superior to amiodarone for acute conversion of recent-onset AF. Both vernakalant and amiodarone were safe and well tolerated in this study. (A Phase III Superiority Study of Vernakalant vs Amiodarone in Subjects With Recent Onset Atrial Fibrillation [AVRO]; NCT00668759).

Special problems with antiarrhythmic drugs in the elderly: safety, tolerability, and efficacy

With advancing age, atrial fibrillation is increasingly likely to indicate underlying cardiovascular disease and risk. An understanding of this is particularly important in the elderly patient, where likely triggers to atrial fibrillation and the influence of other pathologies on the safety and efficacy of proposed treatments will all contribute to optimal care of these patients. It is not yet clear whether rate control or cardioversion to sinus rhythm is the best strategy for the generality of patients with atrial fibrillation, and still less so for individuals. Age and comorbidity add complexities to this decision, which should inform the choice of drugs to be used. Further uncertainties arise from a literature that has often excluded elderly patients and derived its conclusions about mode of drug action from studies undertaken during sinus rhythm rather than atrial fibrillation. Despite these difficulties the careful evaluation of elderly patients with atrial fibrillation and their involvement in relevant choices should ensure optimum treatment for the individual.

Current management of symptomatic atrial fibrillation

Atrial fibrillation (AF) is the commonest arrhythmia. It presents in distinct patterns of paroxysmal, persistent and chronic AF, and patient management aims differ according to the pattern. In paroxysmal AF, drug treatment with beta-blockers, class Ic and class III agents reduce the frequency and duration of episodes. In persistent AF (recent onset, non-paroxysmal), early cardioversion with either pharmacological agents or by direct current (DC) cardioversion should be actively considered, in those patients who are suitable. Patients most likely to cardiovert and remain in sinus rhythm include those with duration of AF of <1 year, an acute reversible cause, left atrial diameter <50 mm and good left ventricular function on echocardiography. Recent data show that maintenance of sinus rhythm after successful cardioversion is enhanced by the use of class III drugs including amiodarone and dofetilide. In chronic or permanent AF, management is aimed at controlling the ventricular rate response with combinations of digoxin, beta-blockers and calcium antagonists with atrio-ventricular nodal activity (diltiazem and verapamil). There is some debate about the prognostic significance of AF. Certainly AF is associated with an excess mortality but this is largely accounted for by its association with serious intrinsic heart disease and the thrombo-embolic complications of the arrhythmia. Atrial fibrillation is a common default arrhythmia for the sick heart.

Comparison between propafenone and digoxin administered intravenously to patients with acute atrial fibrillation. PAFIT-3 Investigators. The Propafenone in Atrial Fibrillation Italian Trial

In recent-onset atrial fibrillation, intravenous propafenone has been shown to effectively restore sinus rhythm, whereas the efficacy of intravenous digoxin has been questioned. We directly compared these 2 drugs and placebo in acute atrial fibrillation. One hundred twenty-three patients with atrial fibrillation lasting <72 hours were randomized to a 10-minute intravenous infusion of either propafenone (2 mg/kg, 41 patients) or digoxin (0.007 mg/kg, 40 patients) or placebo (42 patients). After 1 hour, nonconverted propafenone or digoxin patients were switched to the alternative drug, while nonconverted placebo patients were randomized to either propafenone or digoxin. The observation time ended 1 hour later. By 1 hour, conversion rates were 49% in the propafenone group, 32% in the digoxin group (p = 0.12), and 14% in placebo group (p <0.001 vs propafenone, p = 0.08 vs digoxin). After crossover, digoxin converted 5% of propafenone patients, while propafenone converted 48% of digoxin patients (p <0.05). In the 36 nonconverted placebo patients, sinus rhythm was obtained in 53% of cases with propafenone, and in 5% with digoxin (p < 0.05). Globally, among the 116 patients who received a drug as first treatment, 30 of 60 patients (50%) were converted by propafenone versus 14 of 56 (25%) by digoxin (p <0.01) (odds ratio 2.0, 95% confidence interval 1.19 to 3.36). In nonconverters, the ventricular rate reduction was faster (15 vs 45 minutes) and more prominent (-24% vs -14%) with propafenone than with digoxin. In conclusion, intravenous propafenone terminates atrial fibrillation more effectively than either placebo or intravenous digoxin. In addition, in nonconverted patients, it obtains a more rapid and marked control of the ventricular rate.

[Efficacy and safety of a single oral dose of pilsicainide in supraventricular arrhythmia after coronary artery bypass grafting]

We evaluated the efficacy and safety of administration of a single oral dose of Pilsicainide, a class Ic antiarrhythmic agent, in 34 patients (26 men, 8 women, age from 48 to 81, mean age 66 +/- 8 years) who developed supraventricular arrhythmia after coronary artery bypass grafting (CABG). A total of 42 episodes of postoperative supraventricular arrhythmia, with the majority occurring 2-4 days after CABG, were classified as follows: paroxysmal atrial fibrillation, 34; paroxysmal atrial flutter, 6; and sinus tachycardia, 2. Sinus rhythm was restored in 32 episodes (78%) by treatment with oral pilsicainide given in a single dose of 50 ro 100 mg. Successful conversion was obtained within 90 minutes in 44% and 3 hours in 56% of episodes, with a mean conversion time of 119.2 +/- 107.5 minutes after the administration of pilsicainide. The mean conversion times tended t highlight the difference between the 50 mg and 100 mg doses, but this difference was not statistically significant (p = 0.053). The ventricular rate was significantly reduced from 123.3 +/- 29.5 beats/min to 85.6 +/- 19.9 beats/min (p < 0.0001), however no significant changes in blood pressure or no significant side effects were observed. The results of the present study suggest that a single oral dose of pilsicainide, administered for its favorable pharmacokinetic profile and lack of hemodynamic side effects, is a valuable drug for converting supraventricular arrhythmia to sinus rhythm in most patients after CABG.