[Is radiofrequency catheter ablation available for treatment of ventricular tachycardias?--Effects of sequential unipolar applications using multiple electrode catheter].
The purpose of this study was to examine the effects of radiofrequency energy delivered to the canine endocardium in sequential unipolar applications using multipolar electrode catheter for treatment of ventricular tachycardias. Radiofrequency energy generated by the newly designed device (500 kHz) was delivered to the ventricular myocardium by a quadripolar electrode catheter. The device could indicate output and voltage and could calculate myocardial impedance. In order to determine the power of the ablation in vivo, sequential unipolar application was performed with various output in vitro. A continuous endocardial ablation was achieved with output beyond 15 W and with duration of 5 sec per one pole. According to our measurement, the myocardial impedance in vivo was about three times as large as that in vitro. Therefore, minimal output of 45 W in vivo was applied in the same manner in vitro, which resulted in continuous belt-shaped endocardial ablated lesion. Ventricular stimuli after sequential unipolar applications did not induce ventricular tachycardia in any of the dogs. We conclude that radiofrequency sequential unipolar application using the newly designed device produces a large ablated area and may be suitable for ablation of the foci of ventricular tachycardias.
Ikeda
T
T
Third Department of Internal Medicine, Toho University, School of Medicine Ohashi Hospital.
Ninomiya
K
K
Sugi
K
K
Enjoji
Y
Y
Abe
R
R
Yamaguchi
T
T
Yabuki
S
S
D000818:Animals; D004285:Dogs; D004562:Electrocardiography; D004564:Electrocoagulation / Q000379:methods*; D009206:Myocardium / Q000473:pathology; D013610:Tachycardia / Q000473:pathology / Q000503:physiopathology / Q000601:surgery*