Epicardial pulmonary vein isolation with a hook-shaped cryoprobe to treat atrial fibrillation.
OBJECTIVE
After it was shown that a rapidly firing focus in a pulmonary vein (PV) can cause atrial fibrillation, percutaneous endocardial PV isolation using radiofrequency began to be used as a method of treatment. However, this technique is time consuming. It requires fluoroscopy and contrast media to identify the PV, and cardiac tamponade and PV obstruction are major complications. To overcome these drawbacks, we developed a hook-shaped cryoprobe to enable circumferential ablation of PV orifices epicardially. The aim of this experimental study in dogs was to confirm the efficacy of this method electrophysiologically.


METHODS
Five mongrel dogs (32 PVs) were used. Surrounding tissue was dissected to expose all PVs and their orifices into the left atrium. Each PV was stimulated with an electrode to measure the length of PV which has the same pacing threshold as the left atrium.


RESULTS
The mean distance from the PV orifice to the pacing boundary line was 8.9 +/- 1.3 mm. Encircling cryoablation was performed with a hook-shaped cryoprobe to circumferentially ablate each PV orifice epicardially.


CONCLUSIONS
Cryoablation by this method created a bidirectional conduction block in all PVs. All PVs were electrically isolated, and the PV isolation was achieved epicardially without atriotomy. This method should enable less invasive treatment of AF clinically.
Kubota
Hiroshi
H
Department of Cardiovascular Surgery, University of Kyorin, Tokyo, Japan. kub@kyorin-u.ac.jp
Takamoto
Shinichi
S
Ohtsuka
Toshiya
T
Endo
Hidehito
H
Sato
Masaya
M
Fujiki
Tatsuo
T
Sudo
Kenichi
K
D000818:Animals; D001281:Atrial Fibrillation / Q000503:physiopathology / Q000601:surgery*; D003452:Cryosurgery / Q000295:instrumentation* / Q000379:methods*; D004285:Dogs; D004867:Equipment Design; D006329:Heart Conduction System / Q000503:physiopathology; D011667:Pulmonary Veins / Q000601:surgery*