Clinical comparison of ibutilide and propafenone for converting atrial flutter.
OBJECTIVE
To evaluate the efficacy and safety of intravenous ibutilide and propafenone for immediate treatment of atrial flutter.


METHODS
Forty patients with atrial flutter with an arrhythmia duration of three hours to 90 days were randomized to receive up to two 10-minute infusions of ibutilide (1 and 1 mg) or propafenone (70 and 70 mg) with a 10-minute interval.


RESULTS
Ibutilide was superior to propafenone for treating atrial flutter (90% vs. 30%, p < 0.01). The median conversion time in the ibutilide group was 11 min (the 25th and 75th percentile was 10 and 45 min), and the median conversion time in the propafenone group was 35 min (range 20-55 min). In all patients, the duration of arrhythmia before treatment was a predictor of arrhythmia termination, although this was more obvious in the group that received ibutilide. Conversion of atrial flutter by ibutilide was characterized mainly by increased cycle length variability. Bradycardia (2/20) and hypotension (4/20) were more common side effects with propafenone. Of 20 patients given ibutilide, 8 (40%) who developed monomorphic ventricular extrasystoles or repetitive atrial flutter with aberrant conduction tachycardia, no one required any specific treatment except for the interruption of ibutilide infusion.


CONCLUSIONS
Ibutilide is highly effective for rapidly terminating atrial flutter. This new class III drug, under monitored conditions, is a potential alternative to currently available cardioversion options.
Sun
Jian-Ling
JL
Electrophysiology Group, Department of Cardiology, People's Hospital, Peking University, Xi Zhi Men Nan Da Jie 11, Beijing, 100044, People's Republic of China. sunjianling2000@yahoo.com
Guo
Ji-Hong
JH
Zhang
Nan
N
Zhang
Hai-Cheng
HC
Zhang
Ping
P
D000328:Adult; D000368:Aged; D000889:Anti-Arrhythmia Agents / Q000008:administration & dosage / Q000009:adverse effects / Q000627:therapeutic use*; D001282:Atrial Flutter / Q000188:drug therapy*; D004305:Dose-Response Relationship, Drug; D004311:Double-Blind Method; D004562:Electrocardiography; D005260:Female; D006801:Humans; D007262:Infusions, Intravenous; D008297:Male; D008875:Middle Aged; D011405:Propafenone / Q000008:administration & dosage / Q000009:adverse effects / Q000627:therapeutic use*; D011446:Prospective Studies; D013449:Sulfonamides / Q000008:administration & dosage / Q000009:adverse effects / Q000627:therapeutic use*; D013997:Time Factors; D016896:Treatment Outcome
D000889:Anti-Arrhythmia Agents; D013449:Sulfonamides; C067192:ibutilide; D011405:Propafenone