Intravenous sotalol for the termination of supraventricular tachycardia and atrial fibrillation and flutter: a multicenter, randomized, double-blind, placebo-controlled study. Sotalol Multicenter Study Group

Expedited loading with intravenous sotalol is safe and feasible-primary results of the Prospective Evaluation Analysis and Kinetics of IV Sotalol (PEAKS) Registry

BACKGROUND

Loading of oral sotalol for atrial fibrillation requires 3 days, frequently in the hospital, to achieve steady state. The Food and Drug Administration approved loading with intravenous (IV) sotalol through model-informed development, without patient data.

OBJECTIVE

We present results of the first multicenter evaluation of this recent labeling for IV sotalol.

METHODS

The Prospective Evaluation Analysis and Kinetics of IV Sotalol (PEAKS) Registry was a multicenter observational registry of patients undergoing elective IV sotalol load for atrial arrhythmias. Outcomes, measured from hospital admission until first outpatient follow-up, included adverse arrhythmia events, efficacy, and length of stay.

RESULTS

Of 167 consecutively enrolled patients, 23% were female; the median age was 68 (interquartile range, 61-74) years, and the median CHA2DS2-VASc score was 3 (interquartile range, 2-4). Overall, 99% were admitted for sotalol initiation (1% for dose escalation), with a target oral sotalol dose of either 80 mg twice daily (85 [51%]) or 120 mg twice daily (78 [47%]); 62 patients (37%) had an estimated creatinine clearance ≤90 mL/min. On presentation, 40% of patients were in sinus rhythm, whereas 26% underwent cardioversion before sotalol infusion. In 2 patients, sotalol infusion was stopped for bradycardia or hypotension. In 6 patients, sotalol was discontinued before discharge because of QTc prolongation (3), bradycardia (1), or recurrent atrial arrhythmia (2). The mean length of stay was 1.1 days, and 95% (n = 159) were discharged within 1 night.

CONCLUSION

IV sotalol loading is safe and feasible for atrial arrhythmias, with low rates of adverse events, and yields shorter hospitalizations. More data are needed on the minimal duration required for monitoring in the hospital.

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.

Efficacy and safety of intravenous beta-blockers in acute atrial fibrillation and flutter is dependent on beta-1 selectivity: a systematic review and meta-analysis of randomised trials

BACKGROUND

Intravenous beta-blockers are commonly used to manage patients with acute atrial fibrillation (AF) and atrial flutter (AFl), but the choice of specific agent is often not evidence-based.

METHODS

A prospectively-registered systematic review and meta-analysis of randomised trials (PROSPERO: CRD42020204772) to compare the safety and efficacy of intravenous beta-blockers against alternative pharmacological agents.

RESULTS

Twelve trials comparing beta-blockers with diltiazem, digoxin, verapamil, anti-arrhythmic drugs and placebo were included, with variable risk of bias and 1152 participants. With high heterogeneity (I2 = 87%; p < 0.001), there was no difference in the primary outcomes of heart rate reduction (standardised mean difference - 0.65 beats/minute compared to control, 95% CI - 1.63 to 0.32; p = 0.19) or the proportion that achieved target heart rate (risk ratio [RR] 0.85, 95% CI 0.36-1.97; p = 0.70). Conventional selective beta-1 blockers were inferior for target heart rate reduction versus control (RR 0.33, 0.17-0.64; p < 0.001), whereas super-selective beta-1 blockers were superior (RR 1.98, 1.54-2.54; p < 0.001). There was no significant difference between beta-blockers and comparators for secondary outcomes of conversion to sinus rhythm (RR 1.15, 0.90-1.46; p = 0.28), hypotension (RR 1.85, 0.87-3.93; p = 0.11), bradycardia (RR 1.29, 0.25-6.82; p = 0.76) or adverse events leading to drug discontinuation (RR 1.03, 0.49-2.17; p = 0.93). The incidence of hypotension and bradycardia were greater with non-selective beta-blockers (p = 0.031 and p < 0.001).

CONCLUSIONS

Across all intravenous beta-blockers, there was no difference with other medications for acute heart rate control in atrial fibrillation and flutter. Efficacy and safety may be improved by choosing beta-blockers with higher beta-1 selectivity.

2023 ACC/AHA/ACCP/HRS Guideline for the Diagnosis and Management of Atrial Fibrillation: A Report of the American College of Cardiology/American Heart Association Joint Committee on Clinical Practice Guidelines

AIM

The "2023 ACC/AHA/ACCP/HRS Guideline for the Diagnosis and Management of Atrial Fibrillation" provides recommendations to guide clinicians in the treatment of patients with atrial fibrillation.

METHODS

A comprehensive literature search was conducted from May 12, 2022, to November 3, 2022, encompassing studies, reviews, and other evidence conducted on human subjects that were published in English from PubMed, EMBASE, the Cochrane Library, the Agency for Healthcare Research and Quality, and other selected databases relevant to this guideline. Additional relevant studies, published through November 2022, during the guideline writing process, were also considered by the writing committee and added to the evidence tables, where appropriate.

STRUCTURE

Atrial fibrillation is the most sustained common arrhythmia, and its incidence and prevalence are increasing in the United States and globally. Recommendations from the "2014 AHA/ACC/HRS Guideline for the Management of Patients With Atrial Fibrillation" and the "2019 AHA/ACC/HRS Focused Update of the 2014 AHA/ACC/HRS Guideline for the Management of Patients With Atrial Fibrillation" have been updated with new evidence to guide clinicians. In addition, new recommendations addressing atrial fibrillation and thromboembolic risk assessment, anticoagulation, left atrial appendage occlusion, atrial fibrillation catheter or surgical ablation, and risk factor modification and atrial fibrillation prevention have been developed.

2023 ACC/AHA/ACCP/HRS Guideline for the Diagnosis and Management of Atrial Fibrillation: A Report of the American College of Cardiology/American Heart Association Joint Committee on Clinical Practice Guidelines

AIM

The "2023 ACC/AHA/ACCP/HRS Guideline for the Diagnosis and Management of Patients With Atrial Fibrillation" provides recommendations to guide clinicians in the treatment of patients with atrial fibrillation.

METHODS

A comprehensive literature search was conducted from May 12, 2022, to November 3, 2022, encompassing studies, reviews, and other evidence conducted on human subjects that were published in English from PubMed, EMBASE, the Cochrane Library, the Agency for Healthcare Research and Quality, and other selected databases relevant to this guideline. Additional relevant studies, published through November 2022, during the guideline writing process, were also considered by the writing committee and added to the evidence tables, where appropriate.

STRUCTURE

Atrial fibrillation is the most sustained common arrhythmia, and its incidence and prevalence are increasing in the United States and globally. Recommendations from the "2014 AHA/ACC/HRS Guideline for the Management of Patients With Atrial Fibrillation" and the "2019 AHA/ACC/HRS Focused Update of the 2014 AHA/ACC/HRS Guideline for the Management of Patients With Atrial Fibrillation" have been updated with new evidence to guide clinicians. In addition, new recommendations addressing atrial fibrillation and thromboembolic risk assessment, anticoagulation, left atrial appendage occlusion, atrial fibrillation catheter or surgical ablation, and risk factor modification and atrial fibrillation prevention have been developed.

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.

Clinical Pharmacology-Driven Translational Research to Optimize Bedside Therapeutics of Sotalol Therapy

Oral sotalol, used in adults for sinus rhythm control, is initiated at 80 mg b.i.d. and titrated to a maximum safe dose. The US Food and Drug Administration recommends monitoring the corrected QT interval (QTc ) for at least 3 days, until steady-state exposure of the drug is reached, before patient discharge, which can significantly impact the total cost of treatment. The objectives of this research were to design an accelerated intravenous sotalol loading and maintenance therapy that will reduce the hospital length of stay and to also evaluate the pharmacoeconomic impact in a hospital setting. Pharmacokinetic simulations of sotalol plasma concentrations vs. times profiles were performed to determine the optimal intravenous/oral transition regimen. A cost minimization analysis from the health sector perspective was conducted to assess the cost savings for these proposed accelerated regimens. For a chosen target dose of 120 mg b.i.d., two infusions of 40 mg over 1 hour and 20 mg over 0.5 hour, each followed up by an evaluation of QTc , can be administered followed immediately by the target oral maintenance dose of 120 mg at the end of the second infusion. Consequently, steady-state exposure and, therefore, steady-state QTc are obtained on the first day of therapy, facilitating an earlier hospital discharge. Two and 1-day mean total cost of -$3,123 (95% confidence interval (CI), -$3,640, -$2,607) -$4,820 (95% CI, -$5,352, -$4,288) were observed for this strategy, respectively. We are proposing an intravenous to oral transition strategy for sotalol that has the potential to significantly reduce cost and increase patient convenience.

Does Sotalol Still Have a Role in the Management of Arrhythmias?

Despite proven effectiveness in treating tachyarrhythmias, sotalol is proarrhythmic and can cause torsades de pointes. Given the emergence of studies that show no benefit from rhythm control strategies in managing atrial fibrillation, as well as the introduction of nonpharmacological approaches to treating arrhythmias, we felt it necessary to ascertain if there was any role for sotalol given its side effects. Review of the literature regarding sotalol use in the prevention and treatment of supraventricular and ventricular tachyarrhythmias seems to show that more effective and safer agents and nonpharmacological alternatives are currently available. However, sotalol still seems to be useful in preventing supraventricular tachyarrhythmias postcardiac surgery and in reverting hemodynamically stable sustained ventricular tachycardias in the setting of coronary artery disease. Its role in the prevention of tachyarrhythmias in the setting of arrhythmogenic right ventricular cardiomyopathy requires further investigation.

The Use of Intravenous Sotalol in Cardiac Arrhythmias

Sotalol is a non-selective beta-adrenergic blocking agent without intrinsic sympathomimetic activity. It has the additional unique property of producing pronounced prolongation of the cardiac action potential duration. Sotalol therapy has been indicated for the management of supraventricular arrhythmias, refractory life threatening ventricular arrhythmias and atrial fibrillation/flutter. Until recently, sotalol was only available in the oral form, however, it was approved for intravenous administration by the US Food & Drug Administration (FDA). The current recommendations are for sotalol 75-150mg to be administered intravenously over 5hours. This rate of administration does not reflect the majority of the research that has been performed with regards to intravenous sotalol. Also, the safety of intravenous bolus dosing of 100mg over 1 and 5minutes has previously been demonstrated. The antiarrhythmic action of sotalol depends on its ability to prolong refractoriness in the nodal and extra nodal tissue. Hence, by giving a lower dose over a long duration, patients may not necessarily benefit from its anti-arrhythmic potential. The purpose of this article is to review the research that has been conducted with regards to dosage and safety of intravenous sotalol, its electrophysiological effects and finally the spectrum of arrhythmias in which it has been used to date.

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.

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.

Higher rate of recurrent atrial flutter and atrial fibrillation following atrial flutter ablation after cardiac surgery

INTRODUCTION

Atrial flutter (AFL) is common after cardiac surgery. However, the types of post-cardiac surgery AFL, its response to catheter-based radiofrequency ablation, and its relationship to atrial fibrillation (AF) are unknown.

METHODS AND RESULTS

We retrospectively studied all patients who underwent mapping and ablation for AFL after cardiac surgery from January 1990 to July 2004. One hundred randomly selected patients without prior cardiac surgery (PCS) who underwent mapping and ablation of AFL served as the control population. A total of 236 patients formed the study population (mean age 62 + 13 years, 22% female) and 100 patients formed the control population (mean age 60 + 13 years, 25% female). The majority of patients without PCS had cavo-tricuspid isthmus (CTI)-dependent AFL when compared to patients with PCS (93% vs 72%, respectively, P < 0.0001). In contrast, scar-related AFL was more common in patients with PCS as compared to patients without PCS (22% vs 3%, P < 0.0001). Predictors of scar related AFL in multivariable regression analysis included PCS and left-sided AFL. Acute success rates and complications were similar between the groups. When compared to patients with AFL ablation without PCS, those that had AFL after PCS had higher rates of recurrence of both AFL (1% vs 12%, P < 0.0001; mean time to recurrence 1.85 years) and AF (16% vs 28%, P = 0.02; mean time to recurrence 2.67 years).

CONCLUSION

Despite ablation of AFL, patients with PCS have a higher rate of AFL and AF when compared to patients without PCS who underwent ablation of atrial flutter during long-term follow-up.

New antiarrhythmic agents for atrial fibrillation and atrial flutter

Atrial fibrillation is the most common sustained cardiac arrhythmia and is a frequent reason for antiarrhythmic therapy. Existing antiarrhythmic drugs have important side effects and presently the therapy to maintain sinus rhythm is not superior to a strategy of controlling excessive heart rate. This review summarises current strategies to improve antiarrhythmic therapy for atrial fibrillation. The most important strategies are: i) to develop drugs without proarrhythmic effects--development of drugs devoid of QT prolonging potential is the main strategy; ii) multiple channel-blocking drugs--inspired by the efficacy of amiodarone, several drugs are being developed that have similar electrophysiological properties as amiodarone, but without the extracardiac side effects; iii) drugs that act exclusively in the atria--the atria contain specific potassium channels, and several drugs that act only on these channels are in development; and iv) antiarrhythmic therapy without effects on ion channels--inhibition of the renin-angiotensin system and steroid therapy has been shown to have some effect in the treatment of atrial fibrillation. Many drugs are in development and the therapeutic scenario for treatment of atrial fibrillation may change quickly.

Pharmacological cardioversion of atrial fibrillation: current management and treatment options

Atrial fibrillation (AF) is the most common form of arrhythmia, carrying high social costs. It is usually first seen by general practitioners or in emergency departments. Despite the availability of consensus guidelines, considerable variations exist in treatment practice, especially outside specialised cardiological settings. Cardioversion to sinus rhythm aims to: (i) restore the atrial contribution to ventricular filling/output; (ii) regularise ventricular rate; and (iii) interrupt atrial remodelling. Cardioversion always requires careful assessment of potential proarrhythmic and thromboembolic risks, and this translates into the need to personalise treatment decisions. Among the many clinical variables that affect strategy selection, time from onset is crucial. In selected patients, pharmacological cardioversion of recent-onset AF can be a safely used, feasible and effective approach, even in internal medicine and emergency departments. In most cases of recent-onset AF, pharmacological cardioversion provides an important--and probably more cost effective--alternative to electrical cardioversion, which can then be employed as a second-line therapy for nonresponders. Class IC agents (flecainide or propafenone), which can be safely used in hospitalised patients with recent-onset AF without left ventricular dysfunction, can provide rapid conversion to sinus rhythm after either intravenous administration or oral loading. Although intravenous amiodarone requires longer conversion times, it is still the standard treatment for patients with heart failure. Ibutilide also provides good conversion rates and could be used for AF patients with left ventricular dysfunction (were it not for high costs). For long-lasting AF most pharmacological treatments have only limited efficacy and electrical cardioversion remains the gold standard in this setting. However, a widely used strategy involves pretreatment with amiodarone in the weeks before planned electrical cardioversion: this provides optimal prophylaxis and can sometimes even restore sinus rhythm. Dofetilide may also be capable of restoring sinus rhythm in up to 25-30% of patients and can be used in patients with heart failure. The potential risk of proarrhythmia increases the need for careful therapeutic decision making and management of pharmacological cardioversion. The results of recent trials (AFFIRM [Atrial Fibrillation Follow-up Investigation of Rhythm Management] and RACE [Rate Control versus Electrical Cardioversion for Persistent Atrial Fibrillation]) on rate versus rhythm control strategies in the long term have led to a generalised shift in interest towards rate control. Although carefully designed studies are required to better define the role of pharmacological rhythm control in specific AF settings, this alternative option remains a recommendable strategy for many patients, especially those in acute care.

A randomized, controlled trial of RSD1235, a novel anti-arrhythmic agent, in the treatment of recent onset atrial fibrillation

OBJECTIVES

The purpose of this study was to determine the efficacy and safety of intravenous RSD1235 in terminating recent onset atrial fibrillation (AF).

BACKGROUND

Anti-arrhythmic drugs currently available to terminate AF have limited efficacy and safety. RSD1235 is a novel atrial selective anti-arrhythmic drug.

METHODS

This was a phase II, multi-centered, randomized, double-blinded, step-dose, placebo-controlled, parallel group study. Fifty-six patients from 15 U.S. and Canadian sites with AF of 3 to 72 h duration were randomized to one of two RSD1235 dose groups or to placebo. The two RSD1235 groups were RSD-1 (0.5 mg/kg followed by 1 mg/kg) or RSD-2 (2 mg/kg followed by 3 mg/kg), by intravenous infusion over 10 min; a second dose was given only if AF was present. The primary end point was termination of AF during infusion or within 30-min after the last infusion. Secondary end points included the number of patients in sinus rhythm at 0.5, 1, and 24 h post-last infusion and time to conversion to sinus rhythm.

RESULTS

The RSD-2 dose showed significant differences over placebo in: 1) termination of AF (61% vs. 5%, p < 0.0005); 2) patients in sinus rhythm at 30 min (56% vs. 5%, p < 0.001); 3) sinus rhythm at 1 h (53% vs. 5%, p = 0.0014); and 4) median time to conversion to SR (14 vs. 162 min, p = 0.016). There were no serious adverse events related to RSD1235.

CONCLUSIONS

RSD1235, a new atrial-selective anti-arrhythmic agent, appears to be efficacious and safe for converting recent onset AF to sinus rhythm.

Rapid loading of sotalol or amiodarone for management of recent onset symptomatic atrial fibrillation: a randomized, digoxin-controlled trial

BACKGROUND

Amiodarone and sotalol are commonly used for the maintenance of sinus rhythm, but the efficacy of these agents administered as high-dose infusions for rapid conversion of atrial fibrillation is unknown. Use in this context would facilitate drug initiation in patients in whom ongoing prophylactic therapy is indicated.

METHODS

We assessed the efficacy and safety of rapid high-dose intravenous infusions of amiodarone and sotalol for heart rate control and rapid reversion to sinus rhythm in patients who came to the emergency department with recent-onset symptomatic atrial fibrillation. Patients (n = 140) were randomized to receive 1.5mg/kg of sotalol infused in 10 minutes, 10mg/kg of amiodarone in 30 minutes, or 500 microg of digoxin in 20 minutes. Electrical cardioversion was attempted for patients not converting to sinus rhythm within 12 hours.

RESULTS

The rapid infusion of sotalol or amiodarone resulted in more rapid rate control than digoxin. Each of the 3 trial strategies resulted in similar rates of pharmacological conversion to sinus rhythm (amiodarone, 51%; sotalol, 44%; digoxin, 50%; P = not significant). The overall rates of cardioversion after trial drug infusion and defibrillation were high for all groups (amiodarone, 94%; sotalol, 95%,; digoxin, 98%; P = not significant), but there was a trend toward a higher incidence of serious adverse reactions in the amiodarone group.

CONCLUSION

The rapid infusion of sotalol or amiodarone in patients with symptomatic recent-onset atrial fibrillation results in rapid control of ventricular rate. Even with high-dose rapid infusions, all 3 agents are associated with a poor overall reversion rate within 12 hours. Almost all patients were returned to sinus rhythm with a combination of pharmacological therapy and electrical cardioversion.

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.

Buccal transport of flecainide and sotalol: effect of a bile salt and ionization state

Patients with infrequent attacks of supraventricular arrhythmia may benefit from self administration of antiarrhythmic drugs on an 'as required' basis. The oral cavity is easily accessible and the potential for rapid absorption exists. The effects of ionization state and sodium glycocholate on the ex vivo transport of sotalol and flecainide across porcine buccal mucosa were studied. The permeated amounts at 3 h (Q) and fluxes (J) of sotalol in an aqueous solution at pH 7.4 and 9.0 were similar. At pH 7.4, in contrast to pH 9.0, the addition of 1.0% (w/v) sodium glycocholate decreased Q and J four and five fold. Flecainide base in propylene glycol resulted in a nine and 12 fold higher Q and J as compared with an aqueous solution of flecainide acetate at pH 5.8. The presence of sodium glycocholate reduced the transport rate of the flecainide base. However, Q and J were increased 110 and 75 fold by adding 1.0% (w/v) sodium glycocholate to a solution of flecainide acetate at pH 5.8. Sodium glycocholate seems to be an effective penetration enhancer for the buccal absorption of the more polar ionized form of flecainide in an aqueous solution. Sodium glycocholate does not seem to improve the transport of sotalol.

Conversion of recent-onset atrial fibrillation with intravenous amiodarone: a meta-analysis of randomized controlled trials

STUDY OBJECTIVE

To evaluate efficacy and safety of intravenous amiodarone for conversion of recent-onset atrial fibrillation.

DATA SOURCES

MEDLINE search of published, randomized, controlled trials assessing the efficacy and safety of intravenous amiodarone in recent-onset (< 7 days) atrial fibrillation, supplemented with searches of reference lists of identified articles and bibliographies of secondary and tertiary review articles.

STUDY SELECTION

The identified trials were eligible for meta-analysis if they met the following criteria: patients had recent-onset atrial fibrillation; patients were randomized to intravenous amiodarone, placebo, or another antiarrhythmic agent; no other antiarrhythmic agent except digoxin was administered simultaneously with intravenous amiodarone or other active treatments; the number and percentage of conversions to sinus rhythm after treatment began were reported; and the number and type of adverse drug reactions occurring after treatment began were reported.

RESULTS

Eighteen randomized controlled trials, including active control cohorts and placebo cohorts, met inclusion criteria. Atrial fibrillation was spontaneous in 13 trials, postoperative in 4, and combined spontaneous and postoperative in 1. A total of 550 patients received intravenous amiodarone, 451 received other antiarrhythmic therapy, and 202 received placebo. Unadjusted averages for cardioversion were as follows: intravenous amiodarone, 417 (76%) of 550 patients; other antiarrhythmics, 324 (72%) of 451 patients; and placebo, 121 (60%) of 202 patients. Pooled estimates of cardioversion for active cohort studies were 72.1% for intravenous amiodarone and 71.9% for other antiarrhythmics (p=0.84). Pooled estimates of cardioversion for placebo cohort studies were 82.4% for intravenous amiodarone and 59.7% for placebo (p=0.03). Unadjusted averages for adverse event rates were intravenous amiodarone, 94 (17%) of 550 patients; other antiarrhythmics, 63 (14%) of 451 patients; and placebo, 23 (11%) of 202 patients. Pooled estimates of adverse event rates for active cohort studies were 12.2% for intravenous amiodarone and 14.0% for other antiarrhythmics (p=0.64). Pooled estimates of adverse event rates for placebo cohort studies were 26.8% for intravenous amiodarone and 10.8% for placebo (p=0.02). The most common adverse drug reactions reported with intravenous amiodarone were infusion phlebitis, bradycardia, and hypotension.

CONCLUSION

The efficacy and safety profile of intravenous amiodarone is similar to that of other antiarrhythmics for cardioversion of recent-onset atrial fibrillation. Intravenous amiodarone is significantly more effective than placebo but is associated with significantly higher frequency of adverse events, although most were not considered to be dose limiting.

Effects of intravenous dofetilide on induction of atrioventricular re-entrant tachycardia

OBJECTIVE

To assess the efficacy and safety of intravenous dofetilide in preventing induction of atrioventricular re-entrant tachycardia.

DESIGN

A multicentre, open, dose ranging trial. Fifty one patients with electrically inducible atrioventricular re-entrant tachycardia were allocated to one of five doses of dofetilide (1.5, 3, 6, 9, and 15 microgram/kg), two thirds of the dofetilide dose being given over a 15 minute loading period and the remainder over a 45 minute maintenance period.

MAIN OUTCOME MEASURE

Responders were defined as patients in whom dofetilide prevented reinduction of atrioventricular re-entrant tachycardia at the end of the infusion.

RESULTS

Intravenous dofetilide had no effect on tachycardia inducibility at the two lower doses (1.5 and 3 microgram/kg) but prevented the reinduction of tachycardia at the three higher doses (6, 9, and 15 microgram/kg) at a rate of 36% (11/31). There was a clear relation between plasma dofetilide concentrations and efficacy (p = 0.009). In non-responders, dofetilide increased the cycle length of induced atrioventricular re-entrant tachycardia. Dofetilide increased the atrial and ventricular effective refractory periods, as well as the antegrade and retrograde effective refractory period of the accessory pathway. Treatment related side effects were reported in four patients, one with a new sustained incessant supraventricular tachycardia.

CONCLUSIONS

Dofetilide shows promise as an agent for the prevention of atrioventricular re-entrant tachycardia in patients without structural heart disease.

Frequency-dependent electrophysiological effect of ibutilide on human atrium and ventricle

Most of the class III antiarrhythmic agents developed in recent years blocks the rapid component of delayed rectifier potassium current (IKr). IKr blocker shows reverse use-dependency and also may cause torsades de pointes at slower heart rate. Ibutilide fumarate, a novel class III antiarrhythmic agent, increases window Na(+) current at the action potential plateau phase. We studied the rate-dependent effect of ibutilide on the electrophysiological parameters of human atrium and ventricle. Franz catheter and a pacing catheter were placed closely in the high right atrium and right ventricular apex to record monophasic action potentials (MAP) during pacing at cycle length (PCL) of 600 ms and 350 ms in eight patients who underwent electrophysiological study. MAP duration of right atrium (RA-MAPD) and right ventricle (RV-MAPD), effective refractory period of RA and RV (RA-ERP and RV-ERP), intra-atrial conduction time (IACT) and intra-ventricular conduction time (IVCT) were measured before and after intravenous administration of ibutilide (0.01 mg/kg up to 1mg). A conduction time from RA pacing spike to distal coronary sinus potential was used to measure IACT, while QRS duration of surface ECG during RV pacing was used to measure IVCT. Ibutilide prolonged RA-MAPD by 60 ms at PCL 600 ms and by 53 ms at PCL 350 ms; RV-MAPD by 48 ms at PCL 600 ms and by 55 ms at PCL 350 ms. Ibutilide did not affected RA and RV-ERP/MAPD ratio, IACT, and IVCT. Ibutilide prolongs MAPD and ERP of human atrium and ventricle without reverse use-dependency.

Meta-analysis of the Risk of Torsades de Pointes in patients treated with intravenous racemic sotalol

OBJECTIVE

Intravenous (IV) racemic sotalol is useful for the treatment of multiple tachydysrhythmias. The authors hypothesized that the risk of torsades de pointes (TdP) in patients treated with a single IV infusion of sotalol is lower than the 2-4% risk associated with chronic oral sotalol therapy.

METHODS

A MEDLINE search under the subject heading "sotalol" was made of all publications involving humans written in English or German from 1966 to October 1, 2000. A meta-analysis of all original reports including patients who were given a single infusion of at least 1.5 mg/kg or 100 mg of IV sotalol over 30 minutes or less was performed. Potential variables predictive of TdP were assessed. The primary outcome was the observation of TdP associated with IV sotalol infusion. Secondary measurements included hypotension, bradycardia, and worsening of congestive heart failure. All excluded studies and case reports were also examined for evidence of TdP associated with IV sotalol treatment.

RESULTS

The search included 1,005 publications. There were 37 reports in which 962 patients received IV sotalol and met the inclusion criteria. There was one report of self-terminating TdP lasting 10 seconds among the 962 patients included in the study. There was no report of TdP associated with only IV racemic sotalol administration in any of the excluded studies. If it is assumed that the risk of TdP is homogeneous in the population of patients treated with IV sotalol, then based on the 962 included patients, the rate of TdP is 0.1% (95% CI = 0.003% to 0.6%).

CONCLUSIONS

The overall risk of TdP in patients treated with a single infusion of IV sotalol is low compared with that in patients given chronic oral sotalol therapy.

Antidysrhythmics. Emergent

The emergent treatment of dysrhythmias in the ED continues to evolve. Classic medications such as bretylium and lidocaine are given with newer drugs like amiodarone, ibutilide, and sotalol. Studies in progress will examine their efficacy in the ED. The emergency physician must keep abreast of the growing body of literature.

Termination of recent-onset atrial fibrillation/flutter in the emergency department: a sequential approach with intravenous ibutilide and external electrical cardioversion

Safety and effectiveness are the goals in treating patients with arrhythmias. In an open prospective study, we observed the efficacy and safety of up to 2 mg intravenous ibutilide, a new class III antiarrhythmic agent in haemodynamically stable patients presenting in the emergency department (ED) with symptoms of recent-onset (<48 h) atrial fibrillation/flutter. Arrhythmia termination within 90 min, haemodynamic parameters and proarrhythmic effects were assessed. Non-responders to the ibutilide infusion underwent external electrical cardioversion. We included 51 patients. In 31 patients therapeutic intervention with intravenous ibutilide was successful within 90 min (61%). In another seven patients conversion to sinus rhythm occurred after 90 min without any other intervention (14%). Blood pressure remained stable and no relevant proarrhythmic effects were observed. The 13 patients who did not respond to ibutilide treatment underwent successful external electrical cardioversion. The overall conversion rate was 100%. Forty-seven patients (92%) were discharged within a median of 9 h and managed as outpatients. In conclusion, in haemodynamically stable patients with recent-onset atrial fibrillation/flutter intravenous ibutilide and external electrical cardioversion for conversion to sinus rhythm turned out to be effective and safe. The short duration of admission makes this strategy attractive for use in the ED.

A prospective, randomized controlled trial comparing the efficacy and safety of sotalol, amiodarone, and digoxin for the reversion of new-onset atrial fibrillation

STUDY OBJECTIVE

A prospective, randomized controlled trial of new-onset atrial fibrillation was conducted to compare the efficacy and safety of sotalol and amiodarone (active treatment) with rate control by digoxin alone for successful reversion to sinus rhythm at 48 hours.

METHODS

We prospectively randomly assigned 120 patients with atrial fibrillation of less than 24 hours' duration to treatment with sotalol, amiodarone, or digoxin using a single intravenous dose followed by 48 hours of oral treatment. Patients had ECG monitoring for 48 hours, and time of reversion, adequacy of rate control, and numbers of adverse events were compared. After 48 hours, those still in atrial fibrillation underwent cardioversion according to a standardized protocol. After 48 hours of therapy and attempted cardioversion, the number of patients whose rhythms had successfully reverted were compared.

RESULTS

There was a significant reduction in the time to reversion with both sotalol (13. 0+/-2.5 hours, P <.01) and amiodarone (18.1+/-2.9 hours, P <.05) treatment compared with digoxin only (26.9+/-3.4 hours). By 48 hours, the active treatment group was significantly more likely to have reverted to sinus rhythm than the rate control group (95% versus 78%, P <.05; risk ratio 5.4, 95% confidence interval [CI] 1.5 to 19.2 ). In those patients whose rhythms did not revert to sinus rhythm, there was superior ventricular rate control in the sotalol group at both 24 and 48 hours compared with those who received either amiodarone or digoxin. There were also fewer adverse events in the active treatment group compared with the rate control group.

CONCLUSION

Immediate pharmacologic therapy for new-onset atrial fibrillation with class III antiarrhythmic drugs (sotalol or amiodarone) improves complication-free 48-hour reversion rates compared with rate control with digoxin.

Dofetilide, a new class III antiarrhythmic agent

Dofetilide is a new antiarrhythmic agent recently approved for conversion and maintenance of sinus rhythm in patients with atrial fibrillation (AF) and atrial flutter (AFl). It is a class III antiarrhythmic that works by selectively blocking the rapid component of the delayed rectifier outward potassium current. Dofetilide prolongs the effective refractory period in accessory pathways, both anterograde and retrograde. This can be seen on the electrocardiogram through a dose-dependent prolongation of the QT and QTc intervals, with parallel increases in ventricular refractoriness. Approximately 80% of drug is excreted in urine, so dosing must be based on creatinine clearance. The elimination half-life is approximately 10 hours. In clinical trials dofetilide was superior to flecainide in converting patients with AFl to normal sinus rhythm (NSR; 70% vs 9%, p<0.01). It also was more effective than sotalol in converting patients with both AF and AFl to NSR (29% vs 6%, p<0.05) and maintaining them in NSR for up to 1 year. Most patients converted within 24-36 hours. Dofetilide has a favorable risk:benefit profile. Torsades de pointes is the most serious side effect; it occurs in 0.3-10.5% of patients and is dose related. To minimize the risk of induced arrhythmia, patients who start or restart the drug should be hospitalized a minimum of 3 days for creatinine clearance measurements, continuous electrocardiographic monitoring, and cardiac resuscitation, if necessary.

Appropriate outcome measures in trials evaluating treatment of atrial fibrillation

BACKGROUND

Atrial fibrillation (AF) is a widespread disease that has only recently received the focused attention of arrhythmia specialists despite being the most frequently occurring significant cardiac arrhythmia.

METHODS AND RESULTS

The wide variety of trial designs used to evaluate AF treatment is a reflection of the diverse outcomes associated with this condition. The best trials assess the impact of treatment on a clearly measured outcome that is of clinical relevance to patients. This review discusses the different designs of AF treatment trials and analyzes the utility of the various outcomes that can be assessed.

CONCLUSIONS

A sensible goal of AF treatment is to reduce the frequency of recurrences and to prolong the time between them. The most appropriate trials focus on AF recurrences that are symptomatic and therefore relevant to the patient. We still do not know if there is value in AF prevention, beyond preventing symptoms. However, ongoing and future studies will show whether AF suppression reduces the longer-term risks of stroke or death and improves patient quality of life. Cost of care will increasingly be studied in future trials of AF management.

Cardioversion with sotalol in selected patients with vagally and adrenergically mediated paroxysmal atrial fibrillation

This study was designed to evaluate and compare the effects of oral sotalol for the treatment of vagal and adrenergic paroxysmal atrial fibrillation (PAF). Thirty-five eligible patients with atrial fibrillation of > 12 hours and < 7 days were enrolled in the study. Patients were classified as vagally mediated (group I, n: 14) and adrenergically mediated (group II, n: 21) PAF groups. All patients were given racemic sotalol at a dose up to 120 mg bid for 2 days. At the end of the observation period of 48 hours, 36% of patients (n: five) in group I returned to sinus rhythm. Conversion rate in group II was 71% (n: 15), and this figure was significantly higher than the success rate in group I. Mean times to cardioversion were 22 +/- 15 hours in group I and 16 +/- 14 hours in group II (p < 0.05). The result of this study suggests that oral sotalol is more effective for adrenergic PAF. This beneficial effect of sotalol is not apparent in vagal PAF patients.