Cumulative experience of azimilide-associated torsades de pointes ventricular tachycardia in the 19 clinical studies comprising the azimilide database.
OBJECTIVE
The purpose of this study was to assess the incidence, temporal characteristics, and risk factors associated with azimilide-associated torsades de pointes (TdP) ventricular tachycardia.


BACKGROUND
Azimilide dihydrochloride is a class III antiarrhythmic drug possessing Ikr and Iks channel-blocking properties.


METHODS
Oral azimilide (75 to 125 mg/day) was taken by 5,375 patients in 19 clinical trials conducted at 775 international centers. Of 3,964 patients in double-blind studies, 1,427 had a history of atrial fibrillation or other supraventricular arrhythmia, 510 had an implantable cardioverter-defibrillator, and 2,027 were post-myocardial infarction patients with a left ventricular ejection fraction < or =35%.


RESULTS
The TdP occurred in 56 patients assigned to azimilide, was dose-related, and tended to occur earlier with an azimilide-loading regimen. Forty-three percent of TdP patients had a QT interval corrected by Bazett's formula, for heart rate, (QTc) > or =500 ms at the time of or before the TdP occurrence. Significant risk factors using logistic regression were increasing age, female gender, diuretic use, and lack of aspirin use.


CONCLUSIONS
Azimilide-associated TdP has characteristics and risk factors similar to other Ikr blockers. However, there is a distinctive temporal profile. The TdP events are not concentrated in the first week. The azimilide-associated TdP rate is 1% (95% confidence interval 0.78 to 1.35) and is not increased in patients with low left ventricular ejection fraction, even in women.
Pratt
Craig M
CM
Department of Cardiology, Methodist DeBakey Heart Center, Houston, Texas 77030, USA. cpratt@tmh.tmc.edu
Al-Khalidi
Hussein R
HR
Brum
Jose M
JM
Holroyde
Michael J
MJ
Schwartz
Peter J
PJ
Marcello
Stephen R
SR
Borggrefe
Martin
M
Dorian
Paul
P
Camm
A John
AJ
D000368:Aged; D000889:Anti-Arrhythmia Agents / Q000008:administration & dosage / Q000009:adverse effects* / Q000627:therapeutic use; D001145:Arrhythmias, Cardiac / Q000188:drug therapy / Q000503:physiopathology; D016208:Databases, Factual; D004305:Dose-Response Relationship, Drug; D004562:Electrocardiography; D005260:Female; D006801:Humans; D006827:Hydantoins; D048289:Imidazolidines / Q000008:administration & dosage / Q000009:adverse effects* / Q000627:therapeutic use; D008297:Male; D008875:Middle Aged; D010879:Piperazines / Q000008:administration & dosage / Q000009:adverse effects* / Q000627:therapeutic use; D013997:Time Factors; D016171:Torsades de Pointes / Q000139:chemically induced*
D000889:Anti-Arrhythmia Agents; D006827:Hydantoins; D048289:Imidazolidines; D010879:Piperazines; C086123:azimilide