Circumferential ultrasound ablation for pulmonary vein isolation: analysis of acute and chronic failures.
BACKGROUND
In patients undergoing circumferential isolation of the pulmonary veins with an ultrasound ablation system, we analyzed the temperatures achieved while delivering circumferential ostial lesions in the pulmonary veins. We also reviewed the angiograms obtained during the procedure and identified anatomic variants that could be responsible for ineffective lesion formation.


RESULTS
During the early clinical use in 33 patients, a total of 85 veins were ablated. A mean of 16.9 +/- 12.3 ablations were delivered per patient, and a mean of 6.7 ablations per vein were applied. Entry block was assessed by placing a deflectable octapolar or a circular catheter in the vein. The following anatomic characteristics and technical limitations were identified as possible reasons for ineffective energy delivery: (1) funnel-shaped ostium; (2) ostial diameter larger than the balloon diameter; (3) inability to deliver the catheter to the right inferior or other vein ostia; (4) ostial instability; (5) early branching of the vein; and (6) eccentric position of the ultrasound transducer in the vein. In patients with recurrence of atrial fibrillation, 40% of the ostial lesions reached a temperature >60 degrees C. However, in patients cured by the ablation, 64% of the ostial lesions reached a temperature >60 degrees C (P < 0.06). At least 12 of the 20 chronic recurrences could have been related to technical limitations of the first system. Duration of atrial fibrillation and eccentric deployment of the ultrasound transducer were more frequent in patients with recurrence of arrhythmias at follow-up.


CONCLUSIONS
Ostial anatomy of the veins may affect delivery of ultrasound energy to achieve circumferential lesions. Energy delivery at the ostium with a temperature > 60 degrees C may be important to maximize success. Reconfiguration of the system to overcome the shortcomings identified in the initial experience could increase its performance.
Saliba
Walid
W
The Cleveland Clinic Foundation, Ohio 44195, USA.
Wilber
David
D
Packer
Douglas
D
Marrouche
Nassir
N
Schweikert
Robert
R
Pisano
Ennio
E
Shewchik
Jeannie
J
Bash
Dianna
D
Fanelli
Raffaele
R
Potenza
Domenico
D
Santarelli
Pietro
P
Tchou
Patrick
P
Natale
Andrea
A
D000328:Adult; D000368:Aged; D000889:Anti-Arrhythmia Agents / Q000627:therapeutic use; D001281:Atrial Fibrillation / Q000150:complications / Q000601:surgery*; D017115:Catheter Ablation; D003131:Combined Modality Therapy; D020878:Device Removal; D022062:Electrophysiologic Techniques, Cardiac; D004867:Equipment Design; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008297:Male; D008875:Middle Aged; D011183:Postoperative Complications / Q000209:etiology; D011237:Predictive Value of Tests; D011667:Pulmonary Veins / Q000601:surgery*; D012008:Recurrence; D013318:Stroke Volume / Q000502:physiology; D013997:Time Factors; D017211:Treatment Failure; D014464:Ultrasonic Therapy; D014481:United States
D000889:Anti-Arrhythmia Agents