Procainamide infusion and acute atrial fibrillation

Electrical versus pharmacological cardioversion for emergency department patients with acute atrial fibrillation (RAFF2): a partial factorial randomised trial

BACKGROUND

Acute atrial fibrillation is the most common arrythmia treated in the emergency department. Our primary aim was to compare conversion to sinus rhythm between pharmacological cardioversion followed by electrical cardioversion (drug-shock), and electrical cardioversion alone (shock-only). Our secondary aim was to compare the effectiveness of two pad positions for electrical cardioversion.

METHODS

We did a partial factorial trial of two protocols for patients with acute atrial fibrillation at 11 academic hospital emergency departments in Canada. We enrolled adult patients with acute atrial fibrillation. Protocol 1 was a randomised, blinded, placebo-controlled comparison of attempted pharmacological cardioversion with intravenous procainamide (15 mg/kg over 30 min) followed by electrical cardioversion if necessary (up to three shocks, each of ≥200 J), and placebo infusion followed by electrical cardioversion. For patients having electrical cardioversion, we used Protocol 2, a randomised, open-label, nested comparison of anteroposterior versus anterolateral pad positions. Patients were randomly assigned (1:1, stratified by study site) for Protocol 1 by on-site research personnel using an online electronic data capture system. Randomisation for Protocol 2 occurred 30 min after drug infusion for patients who had not converted and was stratified by site and Protocol 1 allocation. Patients and all research and emergency department staff were masked to treatment allocation for Protocol 1. The primary outcome was conversion to normal sinus rhythm for at least 30 min at any time after randomisation and up to a point immediately after three shocks. Protocol 1 was analysed by intention to treat and Protocol 2 excluded patients who did not receive electrical cardioversion. This study is registered at ClinicalTrials.gov, number NCT01891058.

FINDINGS

Between July 18, 2013, and Oct 17, 2018, we enrolled 396 patients, and none were lost to follow-up. In the drug-shock group (n=204), conversion to sinus rhythm occurred in 196 (96%) patients and in the shock-only group (n=192), conversion occurred in 176 (92%) patients (absolute difference 4%; 95% CI 0-9; p=0·07). The proportion of patients discharged home was 97% (n=198) versus 95% (n=183; p=0·60). 106 (52%) patients in the drug-shock group converted after drug infusion only. No patients had serious adverse events in follow-up. The different pad positions in Protocol 2 (n=244), had similar conversions to sinus rhythm (119 [94%] of 127 in anterolateral group vs 108 [92%] of 117 in anteroposterior group; p=0·68).

INTERPRETATION

Both the drug-shock and shock-only strategies were highly effective, rapid, and safe in restoring sinus rhythm for patients in the emergency department with acute atrial fibrillation, avoiding the need for return to hospital. The drug infusion worked for about half of patients and avoided the resource intensive procedural sedation required for electrical cardioversion. We also found no significant difference between the anterolateral and anteroposterior pad positions for electrical cardioversion. Immediate rhythm control for patients in the emergency department with acute atrial fibrillation leads to excellent outcomes.

FUNDING

Heart and Stroke Foundation of Canada and the Canadian Institutes of Health Research.

Pharmacologic conversion of atrial fibrillation: a systematic review of available evidence

This report reviews the efficacy of currently available antiarrhythmic agents for conversion of atrial fibrilation (AF) to normal sinus rhythm (NSR). A systematic search of literature in the English language was done on computerized databases, such as MEDLINE, EMBASE, and Current Contents, in reference lists, by manual searching, and in contact with expert informants. Published studies involving humans that described the use of antiarrhythmic therapy for conversion of AF to NSR were considered and only studies that examined the use of agents currently available in the United States were included. Studies exclusively describing antiarrhythmic therapy for conversion of postsurgical AF were excluded. The methodology and results of each trial were assessed and attempts were made to acquire additional information from investigators when needed. Assessment of methodological quality was incorporated into a levels-of-evidence scheme. Eighty-eight trials were included, of which 34 (39%) included a placebo group (level I data). We found in recent-onset AF of less than 7 days, intravenous (i.v.) procainamide, high-dose i.v. or high-dose combination i.v. and oral amiodarone, oral quinidine, oral flecainide, oral propafenone, and high-dose oral amiodarone are more effective than placebo for converting AF to NSR. In recent-onset AF of less than 90 days, i.v. ibutilide is more effective than placebo and i.v. procainamide. In chronic AF, oral dofetilide converts AF to NSR within 72 hours, and oral propafenone and amiodarone are effective after 30 days of therapy. We conclude than for conversion of recent-onset AF of less than 7 days, procainamide may be considered a preferred i.v. agent and propafenone a preferred oral agent. For conversion of recent-onset AF of longer duration (less than 90 days), i.v. ibutilide may be considered a preferred agent. For patients with chronic AF and left ventricular dysfunction, direct current cardioversion is the preferred conversion method. Larger, well-designed randomized controlled trials with clinically important endpoints in specific populations of AF patients are needed.

Efficacy of flecainide for the reversion of acute onset atrial fibrillation

The efficacy and safety of intravenous flecainide to convert recent-onset atrial fibrillation (AF) (present for greater than or equal to 30 minutes and less than or equal to 72 hours and a ventricular response greater than or equal to 120 beats/min) was investigated. A total of 102 patients without severe heart or circulatory failure were randomized to receive either intravenous flecainide (2 mg/kg, maximum dose 150 mg; 51 patients) or placebo (51 patients) in a double-blind trial. Digoxin (500 micrograms intravenously) was administered to all patients who had not previously been receiving digoxin. The electrocardiogram was monitored continuously during the study. In 29 (57%) patients stable sinus rhythm was restored within 1 hour after flecainide and in only 7 (14%) given placebo (chi square 18.9; p = 0.000013; odds ratio 8.3; 95% confidence interval 2.9-24.8). Reversion to sinus rhythm within 1 hour after starting the trial medication was considered a pretrial end point and likely to be due to a drug effect. At the end of the 6-hour monitoring period, 34 patients (67%) in the flecainide group were in sinus rhythm whereas only 18 (35%) in the placebo group had reverted (chi square 8.83, p = 0.003; odds ratio 3.67; 95% confidence interval 1.5-9.1). Significant hypotension, although short lived, was more common in the flecainide group. One patient given flecainide developed torsades de pointes and was successfully electrically cardioverted. Flecainide is useful for the management of recent-onset AF both for control of the ventricular response and conversion to sinus rhythm.(ABSTRACT TRUNCATED AT 250 WORDS)

Intravenous procainamide for the conversion of new onset atrial fibrillation in the emergency department setting

A common problem seen by emergency physicians, that of new onset atrial fibrillation, and a unique approach to its emergency department management are discussed. In hemodynamically stable patients with new onset atrial fibrillation, an attempt at chemical cardioversion can be made in the emergency department with intravenous procainamide at a rate of 20 mg/min to a maximum dose of 20 mg/kg if accompanied with careful monitoring of blood pressure and cardiac rhythm. If cardioversion is successful, such individuals may not require hospitalization if they are less than 65 years of age and without evidence of organic heart, lung, or thyroid disease.