Atrial fibrillation therapy in patients with a CRT defibrillator with wireless telemetry.
BACKGROUND
Atrial fibrillation (AF) is a major cause of morbidity and mortality, especially in patients with congestive heart failure.


OBJECTIVE
The purposes of this international, prospective multicenter study were to evaluate the efficacy of atrial shock therapy in patients with a cardiac resynchronization therapy defibrillator (CRT-D) and to evaluate the safety of the new CRT-D. The effectiveness of a new wireless telemetry system was also evaluated.


METHODS
A total of 282 patients, without permanent AF, who had indications for a CRT-D were included. Atrial shock therapy was tested on both spontaneous and induced AF episodes. The effectiveness of the Medtronic wireless telemetry system (Conexus; Medtronic Inc., Minneapolis, MN, USA) was also tested. Secondary endpoints included the heart failure Clinical Composite Response, system performance evaluation, and adverse event summary.


RESULTS
Atrial shock therapy was successful in 168 of 171 episodes (98.2%). Of these, 138 episodes were induced and 33 were spontaneous. Successful cardioversion occurred in 137 of the 138 induced-AF episodes (86.1% with 12 joule (J), 13.1% with 24 J, and 0.7% with 35 J). During the first 3 months of implant, there were 43 system-related complications in 37 subjects out of 278 subjects. There were 1,999 Conexus telemetry uses recorded during this study. This includes 282 uses during the implant procedure. There were no cases of complete loss of telemetry or any adverse events reported using this system.


CONCLUSIONS
We achieved an atrial shock efficacy of 98.2% in patients who met standard CRT-D indications. The wireless telemetry performed well with no reported unanticipated adverse device effects.
Crossley
George H
GH
St. Thomas Research Institute, and Division of Cardiology, University of Tennessee, College of Medicine, Nashville, Tennessee 37203, USA. gcrossley@saintthomasheart.com
Aonuma
Kazutaka
K
Haffajee
Charles
C
Shoda
Morio
M
Meijer
Albert
A
Bauer
Alexander
A
Boriani
Giuseppe
G
Svendsen
Jesper
J
Thomas
Shelley
S
Wiggenhorn
Christopher
C
Unterberg-Buchwald
Christina
C
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001281:Atrial Fibrillation / Q000401:mortality* / Q000517:prevention & control*; D002304:Cardiac Pacing, Artificial / Q000401:mortality* / Q000706:statistics & numerical data; D017147:Defibrillators, Implantable / Q000706:statistics & numerical data*; D005260:Female; D006801:Humans; D015994:Incidence; D038622:Internationality; D008297:Male; D008875:Middle Aged; D015996:Survival Rate; D013686:Telemetry / Q000706:statistics & numerical data*; D016896:Treatment Outcome; D055815:Young Adult