High-dose bolus lidocaine for chemical cardioversion of atrial fibrillation: a prospective, randomized, double-blind crossover trial.
BACKGROUND
Most drugs used for chemical cardioversion of atrial fibrillation have significant proarrhythmia risk and require close monitoring after administration. Lidocaine has few of the proarrhythmic concerns of most antiarrhythmic drugs and, at high bolus doses, prolongs the atrial refractory period well enough to be effective in converting atrial fibrillation to sinus rhythm. This finding has been previously demonstrated in a dog model. We sought to confirm the animal findings in human beings with lidocaine doses of 1.5 to 2.5 mg/kg.


METHODS
Twenty patients with atrial fibrillation scheduled for elective cardioversion were enrolled in this study. In a randomized, double-blind, crossover study design, each patient received intravenous bolus lidocaine or saline. Patients were observed for 10 minutes after the initial bolus to assess efficacy. The second test drug was then delivered if the first was unsuccessful at cardioversion.


RESULTS
All 20 patients received both lidocaine and saline placebo therapy in a crossover manner. None of the 20 patients converted to sinus rhythm with either therapy. The 95% confidence interval for effectiveness of lidocaine in this population was 0% to 14%.


CONCLUSIONS
In this population of patients referred for elective cardioversion of atrial fibrillation, high-dose bolus lidocaine was ineffective in converting patients to sinus rhythm. Although this study was not sufficiently powered to rule out a low efficacy of lidocaine (<15%) or a higher efficacy in certain subgroups of atrial fibrillation, routine use of lidocaine for this indication is not warranted.
Marrouche
N F
NF
Department of Medicine, University of Washington, Seattle, USA.
Reddy
R K
RK
Wittkowsky
A K
AK
Bardy
G H
GH
D000368:Aged; D000889:Anti-Arrhythmia Agents / Q000008:administration & dosage* / Q000009:adverse effects / Q000627:therapeutic use; D001281:Atrial Fibrillation / Q000188:drug therapy* / Q000503:physiopathology; D018592:Cross-Over Studies; D004305:Dose-Response Relationship, Drug; D004311:Double-Blind Method; D005260:Female; D006339:Heart Rate / Q000187:drug effects; D006801:Humans; D007275:Injections, Intravenous; D008012:Lidocaine / Q000008:administration & dosage* / Q000009:adverse effects / Q000627:therapeutic use; D008297:Male; D008875:Middle Aged; D009325:Nausea / Q000139:chemically induced; D009422:Nervous System Diseases / Q000139:chemically induced; D011446:Prospective Studies; D017211:Treatment Failure
D000889:Anti-Arrhythmia Agents; D008012:Lidocaine