Beta-radiation for the creation of linear lesions in the canine atrium.
BACKGROUND
Creating linear lesions is important for the treatment of arrhythmias such as atrial flutter and fibrillation. Making these lesions with standard radiofrequency catheters can be difficult and may result in charring and thrombosis. The purpose of this study was to evaluate beta-radiation as a novel energy source for creating linear myocardial lesions.


RESULTS
Eight dogs with intact conduction across the cavotricuspid isthmus were studied. The isthmus was irradiated (25 to 50 Gy) with strontium/yttrium-90 delivered via a deflectable 7F catheter (Novoste Corporation). There were no immediate effects, but bidirectional conduction block developed during follow-up studies in 7 of 8 dogs. The dog without conduction block received 25 Gy. After the animals were euthanized, histology revealed transmural, linear areas of fibrosis without any thrombus.


CONCLUSIONS
Beta-radiation can safely and effectively create linear lesions that are contiguous and nonthrombogenic. This energy source may become an interesting adjunct to radiofrequency for the treatment of atrial flutter and fibrillation.
Department of Medicine and Research Center, Montreal Heart Institute, 5000 Belanger East, Montreal, Quebec, Canada H1T 1C8. p_guerra@icm-mhi.com
Peter G
PG
Guerra
Mario
M
Talajic
Bernard
B
Thibault
Marc
M
Dubuc
Denis
D
Roy
Laurent
L
Macle
Tack Ki
TK
Leung
André
A
Arsenault
François
F
Harel
Jean
J
Grégoire
Raoul
R
Bonan
D000818:Animals; D001145:Arrhythmias, Cardiac / Q000532:radiotherapy*; D001610:Beta Particles / Q000009:adverse effects / Q000627:therapeutic use*; D002304:Cardiac Pacing, Artificial; D004285:Dogs; D005355:Fibrosis; D006325:Heart Atria / Q000473:pathology / Q000528:radiation effects*; D006327:Heart Block / Q000209:etiology; D006329:Heart Conduction System / Q000528:radiation effects; D011833:Radiation Injuries, Experimental / Q000209:etiology