Effectiveness of intravenous propafenone for conversion of recent-onset atrial fibrillation: a 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.

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 ).

Reappraising the role of class Ic antiarrhythmics in atrial fibrillation

PURPOSE

The objective of the present systematic review was to compare the effectiveness and safety of class Ic agents for cardioversion of paroxysmal atrial fibrillation (AF), in patients with and without structural heart disease (SHD).

METHODS

We focused on RCTs enrolling at least 50 adult patients with electrocardiogram-documented paroxysmal AF that compared either two pharmacological class Ic cardioversion agents (flecainide, propafenone), regardless of study design (parallel or crossover). We searched MEDLINE and the Cochrane Central Register of Controlled Trials. Initial search was performed from inception to 15 July 2021 with no language restrictions.

RESULTS

Intravenous flecainide is the most effective option for pharmacologic cardioversion of AF since only 2 patients need to be treated in order to cardiovert one more within 4 h. Most importantly, class Ic agents appear to be safe in the context of pharmacologic cardioversion of AF irrespective of the presence of SHD, pointing towards a possible reappraisal of the role in this setting.

CONCLUSION

We suggest that class Ic agents (with flecainide appearing to be more effective) should be used for pharmacologic cardioversion in stable AF patients presenting in emergency department with unknown medical history, after excluding severe cardiac disease through a bedside examination.

REGISTRATION NUMBER (DOI)

Available in https://osf.io/apwt7/ , https://doi.org/10.17605/OSF.IO/APWT7.

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.

Significant Increase in C-Reactive Protein and Serum Amyloid A in the Early Hours of Paroxysmal Atrial Fibrillation

Background

A number of data have been accumulated on inflammation in persistent and permanent atrial fibrillation (AF). Our aim was to study the process in paroxysmal AF (PAF) by measuring plasma concentrations of high-sensitivity C-reactive protein (hs-CRP), serum amyloid A (SAA) and fibrinogen in dynamics.

Methods

The markers were investigated in 51 patients (26 males and 25 females; 59.84 ± 1.60 years) at hospital admission (baseline), 24 hours and 28 days after sinus rhythm restoration. Fifty-two controls (26 males and 26 females; 59.50 ± 1.46 years) were selected.

Results

At baseline, hs-CRP and SAA concentrations were higher in patients (8.12 ± 0.82 vs. 5.57 ± 0.21 mg/L, P = 0.003; 16.04 ± 0.93 vs. 5.12 ± 0.23 ng/mL, P < 0.001, respectively) and these changes persisted 24 hours after sinus rhythm restoration (8.16 ± 0.71 vs. 5.57 ± 0.21 mg/L, P < 0.001; 12.99 ± 0.75 vs. 5.12 ± 0.23 ng/mL, P < 0.001, respectively). On the 28th day, no significant difference was measured (5.42 ± 0.29 vs. 5.57 ± 0.21 mg/L, P = 0.68; 5.89 ± 0.38 vs. 5.12 ± 0.23 ng/mL, P = 0.08, respectively). At any measurement, fibrinogen levels did not differ between patients and controls (3.30 ± 0.17 vs. 3.22 ± 0.11 g/L, P = 0.70; 3.32 ± 0.11 vs. 3.22 ± 0.11 g/L, P = 0.52; 3.24 ± 0.13 vs. 3.22 ± 0.11 g/L, P = 0.90, respectively).

Conclusion

PAF is associated with dynamics in hs-CRP and SAA plasma levels. The results suggest that inflammation is closely related to the arrhythmia initiation.

Early effects of paroxysmal atrial fibrillation on plasma markers of fibrinolysis

There are no studies to date on the early changes in the hemostasis profile of patients with paroxysmal atrial fibrillation (PAF).Given the key role of the fibrinolytic system in maintaining blood fluidity, our aim was to examine its activity in patients with clinical manifestation of the disease <24 hours.We studied 51 nonanticoagulated patients with a first episode of the disease (26 men, 25 women; mean age 59.84 ± 1.60 years) and 52 controls (26 men, 26 women; mean age 59.50 ± 1.46 years) who matched the patients in terms of gender, age, comorbidities, and conducted treatment. Using enzyme-linked immunoassays and colorimetric assays we assessed the plasminogen activity, tissue plasminogen activator level (t-PA), plasminogen activator inhibitor 1 activity (PAI-1), α2-antiplasmin activity (α2-AP), D-dimer level, and vitronectin level. Blood samples were collected immediately after hospitalization.Patients were hospitalized between the second and twenty fourth hours (mean 8.14 ± 0.76 hours) after the onset of PAF. Compared to controls, plasminogen (159.40 ± 4.81 vs 100.2 ± 2.88%, P < 0.001) and t-PA levels (11.25 ± 0.35 vs 6.05 ± 0.31 ng/mL, P < 0.001) were significantly higher in the patient group. PAI-1 activity (7.33 ± 0.37 vs 15.15 ± 0.52 AU/mL, P < 0.001) and α2-AP (112.9 ± 2.80 vs 125.60 ± 3.74%, P < 0.05) as well as vitronectin plasma levels (134.7 ± 5.83 vs 287.3 ± 10.44 mcg/mL, P < 0.001) were lower in the PAF group. Conversely, the levels of D-dimer in patients were significantly higher (0.53 ± 0.07 vs 0.33 ± 0.02 ng/mL, P < 0.05).Early changes in the fibrinolytic system occur in PAF, suggesting their close relationship with the manifestation of the disease. There is high plasma fibrinolytic activity, during the very first 24 hours of the disease, which is most likely a pathophysiological response to the intensified procoagulation process.

Early Changes in the Antithrombin and Thrombin-Antithrombin Complex in Patients With Paroxysmal Atrial Fibrillation

Background

Data on coagulation changes in paroxysmal atrial fibrillation (PAF) are scarce. The aim of this study was to examine plasma antithrombin (AT) levels and activity as well as thrombin-antithrombin (TAT) complex levels in the early hours of the clinical manifestation of PAF.

Methods

Fifty-one patients (26 men and 25 women; mean age 59.84 ± 1.60 years) were consecutively selected with PAF duration < 24 hours, and 52 controls (26 men and 26 women; mean age 59.50 ± 1.46 years) matched the patients in terms of gender, age and comorbidities. Plasma levels and activity of AT and levels of the covalent TAT complex were studied once in each study participant.

Results

AT plasma levels in PAF patients were statistically significantly lower compared to controls (164.69 ± 10.51 vs. 276.21 ± 8.29 μg/mL, P < 0.001). Plasma activity of the anticoagulant was also significantly lower in PAF (71.33±4.87 vs. 110.72±3.09%, P < 0.001). TAT complex concentration in plasma was higher in the patient group (5.32 ± 0.23 vs. 3.20 ± 0.14 μg/L, P < 0.001).

Conclusion

We can say that PAF is associated with significantly reduced AT levels and activity and increased levels of TAT complex during the first 24 hours after its manifestation. These changes indicate a reduced activity of AT anticoagulant system, which is a probable prerequisite for the established enhanced coagulation (high TAT complex levels).

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.

Atrial Fibrillation: Modern Concepts and Management

Atrial fibrillation (AF) is a common cardiac arrhythmia responsible for significant morbidity and mortality. In recent years, progress has been made in determining the genetic abnormalities that may lead to AF. New trials have shown that rate control and anticoagulation are acceptable as a primary treatment strategy in many patients who have a high risk of recurrence. Newer and safer antiarrhythmics are now available. Pacemaker and implantable cardiac defibrillator technology is rapidly evolving and may play a significant role in future treatment and prevention of AF. Direct thrombin inhibitors are likely to add a user-friendly option to the current standard therapy for stroke prevention.

Impact of informed consent requirements on cardiac arrest research in the United States: exception from consent or from research?

INTRODUCTION

Research in patients with life-threatening illness such as cardiac arrest is challenging since they can not consent. The Food and Drug Administration addressed research under emergency conditions by publishing new criteria for exception from informed consent in 1996. We systematically reviewed randomized trials over a 10-year period to assess the impact of these regulations.

METHODS

Case-control study of published trials for cardiac arrest (cases) and atrial fibrillation (controls.) Studies were identified by using structured searches of MEDLINE and EMBASE from 1992 to 2002. Included were studies using random allocation in humans with cardiac arrest or atrial fibrillation prior to enrollment. Excluded were duplicate publications. Number of American trials, foreign trials and proportion of trials of American origin were compared by using regression analysis. Changes in cardiac arrest versus atrial fibrillation trials were calculated as risk differences.

RESULTS

Of 4982 identified cardiac arrest studies, 57 (1.1%) were randomized trials. The number of American cardiac arrest trials decreased by 15% (95% CI: 8, 22%) annually (P = 0.05). The proportion of cardiac arrest trials of American origin decreased by 16% (95% CI: 10, 22%) annually (P = 0.006). Of 5596 identified atrial fibrillation studies, 197 trials (3.5%) were randomized trials. The risk difference between cardiac arrest versus atrial fibrillation trials being of American origin decreased significantly (annual difference -5.8% (95% CI: -10, -0.1%), P = 0.03).

INTERPRETATION

Fewer American cardiac arrest trials were published during the last decade, when federal consent requirements changed. Regulatory requirements for clinical trials may inhibit improvements in care and threaten public health.

Review of the current management of atrial fibrillation

Atrial fibrillation (AF) is the most common sustained arrhythmia. Its prevalence is increasing and accordingly, so is its burden on healthcare systems throughout the world. The pathophysiology of AF is complex and poorly understood, which of itself presents a major challenge to the management of this important condition. AF is associated with increased morbidity and mortality, particularly in patients with underlying left ventricular dysfunction. Once AF occurs, it is often difficult to 'cure' and as such, the major focus of therapy is currently divided essentially between a rate control strategy and a need to revert to and maintain sinus rhythm. Both approaches seek to minimise the associated symptoms and complications. Over the past two decades, numerous pharmacological approaches to the management of AF have been employed, many of which have been shown to be relatively ineffective or confounded by major complications. Accordingly, recent research and interest has focused on non-pharmacological electrophysiological therapies to either cure AF or improve symptoms. This review summarises the current approaches to the management AF and provides some new insights into emerging therapies for this common clinical problem.

Amiodarone versus placebo and class Ic drugs for cardioversion of recent-onset atrial fibrillation: a meta-analysis

OBJECTIVES

This meta-analysis compared amiodarone with placebo and class Ic drugs for the cardioversion of recent-onset atrial fibrillation (AF), defined as lasting less than seven days.

BACKGROUND

Despite the lack of trials that support its efficacy convincingly, amiodarone is widely used for conversion of recent-onset AF.

METHODS

We searched Medline and EMBASE databases, as well as the Cochrane Controlled Trials Register for randomized trials on recent-onset AF comparing amiodarone to placebo or class Ic drugs. Data were combined according to a fixed effect model. The primary end point was the rate of conversion at 24 h. To study time-dependency of the drugs, efficacy at 1 to 2 h, 3 to 5 h, 6 to 8 h, and at 24 h was analyzed.

RESULTS

We found six studies randomizing amiodarone versus placebo (595 patients) and seven studies versus class Ic drugs (579 patients). There was no significant difference between amiodarone and placebo at 1 to 2 h, but significant efficacy was found after 6 to 8 h (relative risk [RR] 1.23, p = 0.022) and at 24 h (RR 1.44, p < 0.001). Efficacy with amiodarone was inferior to class Ic drugs for up to 8 h (RR 0.67, p < 0.001) but no difference was seen at 24 h (RR 0.95, p = 0.50). There were no major adverse effects.

CONCLUSIONS

Amiodarone is superior to placebo for cardioversion of AF, and even though the onset of conversion is delayed, its efficacy is similar at 24 h compared with class Ic drugs. These results favor amiodarone as a reasonable alternative for patients with recent AF in whom class Ic and other, more rapidly acting antiarrhythmic drugs cannot be used.

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.

Meta-analysis of randomised controlled trials of the effectiveness of antiarrhythmic agents at promoting sinus rhythm in patients with atrial fibrillation

OBJECTIVE

To conduct a meta-analysis of randomised controlled trials to estimate the effectiveness of antiarrhythmic drugs at promoting sinus rhythm in patients with atrial fibrillation.

DESIGN

Articles were identified by using a comprehensive search of English language papers indexed in Medline from 1966 to August 2001. For the outcomes of sinus rhythm and death, a random effects model was used to model repeated assessments within a study at different time points.

SETTING

Emergency departments and ambulatory clinics.

PATIENTS

Patients with atrial fibrillation.

INTERVENTIONS

Antiarrhythmic agents grouped according to their Vaughan-Williams class.

MAIN OUTCOME MEASURES

Sinus rhythm and mortality.

RESULTS

91 articles met a priori criteria for inclusion in the analysis. Median duration of follow up was one day (range 0.04-1096, mean (SD) 46 (136) days). The median proportion of patients in sinus rhythm at follow up was 55% (range 0-100%) and 32% (range 0-90%) receiving active treatment and placebo, respectively. Median survival was 99% (range 55-100%) and 99% (range 55-100%). Compared with placebo, the following drug classes were associated with increased sinus rhythm at follow up: IA (treatment difference 21.5%, 95% confidence interval (CI) 16.3% to 26.8%); IC (treatment difference 33.1%, 95% CI 23.3% to 42.9%); and III (treatment difference 17.4%, 95% CI 11.5% to 23.3%). Class IC drugs were associated with increased sinus rhythm at follow up compared with class IV drugs (treatment difference 43.2%, 95% CI 11.5% to 75.0%). There was no significant difference in mortality between any drug classes.

CONCLUSIONS

Class IA, IC, and III drugs are associated with increased sinus rhythm at follow up compared with placebo. It is unclear whether any antiarrhythmic drug class is associated with increased or decreased mortality.

Oral loading with propafenone for conversion of recent-onset atrial fibrillation: a review on in-hospital treatment

Atrial fibrillation (AF) is a very common arrhythmia. In order to treat acute AF rapidly, effective drug regimens are required. Propafenone is a class IC antiarrhythmic agent that is suitable for oral loading as it reaches peak plasma concentrations within 2 to 4 hours of administration. The use of propafenone loading in patients with AF must be based on appropriate patient selection in view of the negative inotropic effect and the potential proarrhythmic effects of the drug. A series of controlled trials in patients with recent-onset AF without heart failure who were hospitalised with enforced bed rest has shown that orally loaded propafenone (450 to 600 mg as single dose) exerts a relatively quick effect (within 3 to 4 hours) and a high rate of efficacy (72 to 78% within 8 hours). A potentially harmful effect of class IC agents is the risk of transforming AF into atrial flutter (3.5 to 5% of patients). However, atrial flutter with 1 : 1 atrioventricular response was observed in only two of 709 patients receiving propafenone (0.3% incidence). Nevertheless, the potential negative inotropic effect of propafenone demands careful patient selection, with systematic exclusion of patients with left ventricular dysfunction or congestive heart failure. Oral loading with propafenone can be considered as an episodic treatment in patients with AF recurrences, as has been proposed for other drugs in the past. However, the safety of oral loading with propafenone as an outpatient treatment in appropriately selected patients has to be assessed by appropriately designed prospective studies.

Intravenous antiarrhythmic agents

Intravenous antiarrhythmic drugs can be used as diagnostic tools; for example, adenosine can be used to reveal the underlying rhythm in narrow QRS tachycardia. Newer class III antiarrhythmic agents, like ibutilide and dofetilide, are effective at the conversion of acute atrial fibrillation; however, electrical cardioversion is still the most effective method for restoration of sinus rhythm in persistent atrial fibrillation. Lidocaine and bretylium in the treatment and prevention of ventricular tachyarrhythmia are de-emphasized because of inefficacy, safety concerns (lidocaine), or shortage of drug (bretylium). Procainamide is effective for stable ventricular tachycardia, and amiodarone is effective in the treatment of shock-refractory ventricular fibrillation. Adrenergic blockade is likely important in the management of tachyarrhythmias, particularly in electrical storm, but more data will be necessary to establish its role.

Management of postoperative arrhythmias

Arrhythmias occur commonly in patients after cardiac surgery. Atrial fibrillation is the most common arrhythmia in the postoperative period; it accounts for significant morbidity to the patient and prolonged hospital stays, and it contributes significantly to the cost of hospitalization. It occurs more commonly in elderly men and in patients undergoing valvular procedures. Beta blockers are effective agents that keep patients from developing postoperative atrial fibrillation and help maintain ventricular rate control. Prophylaxis with antiarrhythmic agents such as amiodarone and sotalol and recently with atrial pacing have shown promise in recent randomized trials. Patients with atrial fibrillation that persists for longer than 48 hours appear to be at a greater risk for cerebroembolic events and should receive anticoagulation unless a contraindication exists. Although frequent premature ventricular contractions and nonsustained ventricular tachycardia (NSVT) occur frequently in patients after cardiac surgery, sustained ventricular tachycardia and ventricular fibrillation are rare and are associated with a poor prognosis. Polymorphic ventricular tachycardia may occur in the setting of myocardial ischemia, metabolic disturbances, and drug toxicities (including antiarrhythmic agents used to treat atrial fibrillation). Poor left ventricular function is a potent risk factor for sudden death in patients with NSVT. Patients with persistent NSVT and ischemic cardiomyopathy with left ventricular ejection fractions of less than 40% should undergo electrophysiologic testing. Conduction abnormalities that may be encountered in patients after cardiac surgery are rarely life threatening. Patients who have undergone valve replacement or repair are at higher risk of developing significant bradyarrhythmias that may require temporary pacing.

Pharmacotherapy of atrial fibrillation

Atrial fibrillation (AF) remains a widespread health problem and the drugs available for its treatment suffer from several drawbacks, including potentially lethal proarrhythmia, serious non-cardiac toxicity and limited efficacy. The evidence for efficacy of currently available anti-arrhythmic agents for sinus rhythm restoration and maintenance is reviewed, with emphasis on randomised trials when available. The current approach to thromboembolism prophylaxis in AF is summarised.

Comparison of propafenone versus procainamide for the acute treatment of atrial fibrillation after cardiac surgery

A prospective, randomized, double-blind study to compare the efficacy in terminating postoperative atrial fibrillation of the class Ic drug propafenone versus class Ia drug procainamide was conducted. Intravenous propafenone was superior to procainamide in achieving rapid cardioversion and a better rate control with a lower incidence of symptomatic hypotension.

Placebo-controlled evaluations of propafenone for atrial tachyarrhythmias

This review summarizes the results of placebo-controlled trials of propafenone, a class IC antiarrhythmic drug, in patients with supraventricular tachycardia, atrial fibrillation (AF), and atrial flutter. Success rates for cardioversion from AF or flutter to sinus rhythm of 9-93% have been obtained with intravenous propafenone. The duration of arrhythmia is an important factor in the degree of success. The use of a single oral dose has also been reported to be effective in a number of studies. Several placebo-controlled studies have confirmed the effectiveness of propafenone in the long-term suppression of both suproventricular tachycardia and AF and flutter. These reported trials have shown consistent benefit with propafenone compared with placebo in preventing arrhythmia recurrence. The adverse side effect profile for propafenone has also been reviewed with particular reference to the potential for proarrhythmia. The rate of side effects is dose-dependent and tends to be higher in patients with underlying structural heart disease. Overall propafenone has been shown to be an effective antiarrhythmic drug with an acceptable side effect profile for the acute and long-term treatment of supraventricular arrhythmias.

Rhythm management in atrial fibrillation--with a primary emphasis on pharmacological therapy: Part 2

Atrial fibrillation (AF) is the most common, sustained, symptomatic tachyarrhythmia that clinicians are called upon to manage. Management strategies include ventricular rate control coupled with anticoagulation, versus restoration and maintenance of sinus rhythm. Rate control may be achieved pharmacologically, with agents that impair AV nodal conduction directly and/or by increasing parasympathetic/sympathetic balance, or by modifying or ablating the AV nodal region anatomically. Rhythm control may be achieved by electrical or pharmacological conversion followed by maintenance of sinus rhythm by pharmacological (or occasionally ablative) therapies. This article will present current approaches to rate and rhythm control issues in AF. Part 1, published previously, dealt with rate control. Part 2, the current article, details approaches to the restoration of sinus rhythm by electrical and pharmacological means. The former may use transthoracic or catheter-based energy delivery systems. The latter may use intravenous or oral drug approaches. Part 3, to be published in a subsequent edition of PACE will deal with the maintenance of sinus rhythm.

The medical management of atrial fibrillation

Atrial fibrillation is an extremely common arrhythmia that is associated with significant sequelae. Certain aspects of therapy, such as anticoagulation, are studied in well-constructed randomized trials. Other therapy, such as the maintenance of sinus rhythm with antiarrhythmic agents, is supported by limited evidence. This article reviews the epidemiology and medical treatment of this arrhythmia, addressing anticoagulation, ventricular rate control, and restoration and maintenance of sinus rhythm. Randomized trials in progress that attempt to answer important questions in the management of atrial fibrillation are also discussed.

Intravenous Propafenone for Conversion of Atrial Fibrillation or Flutter to Sinus Rhythm: A Randomized, Placebo-controlled, Crossover Study

BACKGROUND: Propafenone has been claimed to be effective in converting atrial fibrillation and flutter to sinus rhythm; however, controlled clinical trials have reported variable results, and data about the safety of propafenone in the setting of heart failure are lacking. The aim of the present study was to evaluate the efficacy and safety of intravenous propafenone in converting atrial fibrillation and flutter to sinus rhythm. METHODS: Sixty patients with acute (<72 h) or chronic atrial fibrillation or flutter were included in a randomized, placebo-controlled, conditional cross-over study. Twenty eight patients, of whom 12 were in New York Heart Association class III and IV, had heart failure. Patients received intravenous propafenone (2 mg/kg in 10 minutes) and placebo subsequently at 1 hour intervals if sinus rhythm was not achieved. The patients' rhythms were continuously monitored for 1 hour and a 12-lead electrocardiogram, a 1-minute continuous rhythm strip and vital signs were recorded at baseline and at 15, 30, 45, and 60 minutes after the administration of each drug. RESULTS: Twenty of teh 59 patients (34%) treated with propafenone converted to sinus rhythm, while only 4 of the 50 patients (8%) treated with placebo converted (P <.001). Propafenone was more effective in patients with acute (<72 h) atrial fibrillation (64.5%). The conversion rate with propafenone was not significantly different from placebo in patients with atrial flutter and chronic atrial fibrillation (>72 h). Propafenone significantly decreased (P <.005 vs placebo) mean ventricular rate in nonresponders with a baseline heart rate of more than 100 beats/min. No clinically significant adverse effect occurred. CONCLUSIONS: We conclude that intravenous propafenone treatment is effective for converting acute atrial fibrillation; however, it seems unlikely to be beneficial in atrial flutter and chronic atrial fibrillation. Propafenone decreases ventricular rate in nonresponders, and a single dose of propafenone is relatively safe even in moderate-to-severe heart failure.

Antiarrhythmic drug therapy in the management of atrial fibrillation

Antiarrhythmic drugs have been used for the acute conversion of atrial fibrillation to sinus rhythm, as well as for the long-term maintenance of sinus rhythm. In recent years, concerns regarding antiarrhythmic drug efficacy as well as safety have prompted a re-examination of the indications for antiarrhythmic therapy in patients with atrial fibrillation. This review will focus on the safety and efficacy of antiarrhythmic therapy in the acute and chronic management of patients with atrial fibrillation.

Management of atrial fibrillation after coronary artery bypass graft

More than 400,000 patients undergo coronary artery bypass graft surgery (CABG) each year in the United States. At least 20-30% of these patients have atrial fibrillation (Afib), making this arrhythmia one of the most common postoperative problems. This generally benign problem can increase surgical morbidity and the cost and length of hospital stay. If not treated promptly and effectively, Afib can delay a full and rapid recovery. Afib usually occurs in paroxysms between the second and fifth postoperative day and appears directly related to effects of surgery (pericarditis, changes in autonomic tone, cardioplegia, myocardial damage, fluid shifts, etc.). Although similar to Afib in other settings, beta-adrenergic blockade is more effective in preventing and terminating Afib in the postoperative setting. The unique circumstances that precipitate postoperative Afib may explain the favorable therapeutic and prophylactic actions of beta-adrenergic blockade. Other therapies such as amiodarone, sotalol, and digoxin are surprisingly ineffective for postoperative Afib, while intravenous diltiazem is not well tested in this setting. Despite the lack of proven benefit for some of these therapies, they are still frequently used in current clinical practice. Management of postoperative Afib is initially directed at ventricular rate control, but the ultimate goal is return to sinus rhythm. The approach to therapy depends on several clinical variables, including the time course of the arrhythmia, but hemodynamic stability of the patient is the key issue. Return to sinus rhythm may be difficult to achieve early after surgery, so opting for rate control is the best initial approach. If tolerated, beta-adrenergic blockade and calcium antagonism are the best first options. Class IA and III antiarrhythmic drugs should be reserved for persistent or poorly tolerated and prolonged episodes of Afib. Elective cardioversion, either by direct current or with drugs, should be delayed for as long as possible after surgery. Anticoagulation for post-CABG Afib remains controversial. More prudent use of presently available drugs to treat Afib could reduce morbidity, cost, and duration of hospital stay after CABG. More rapid-acting and reliably effective antiarrhythmic therapies with minimal adverse effects would greatly improve management of post-CABG Afib.