Effect of isthmus anatomy and ablation catheter on radiofrequency catheter ablation of the cavotricuspid isthmus.
BACKGROUND
Cavotricuspid isthmus (CTI) characteristics are rarely documented when comparing catheters in radiofrequency ablation (RFA) of atrial flutter (AFL). Our objectives were (1) to evaluate the impact of CTI morphology and length on ablation procedures and (2) to compare the efficacy of an 8-mm-tip catheter with an irrigated cooled-tip RFA in the subgroup presumed to be more difficult to treat (with a long CTI, >35 mm).


RESULTS
Over a period of 17 months, 185 patients accepted the protocol and underwent an isthmogram in preparation for RFA. Groups were classified according to CTI length and CTI morphology. RFA was performed with an 8-mm-tip catheter for patients with a short CTI, < or =35 mm (n=123), whereas randomization between an 8-mm-tip and a cooled-tip catheter applied to patients with a longer CTI, >35 mm (n=62). For long CTI, 32 patients were assigned to an 8-mm catheter and 30 patients to the cooled-tip RFA ablation group. In this subset, RF application (18.2+/-17 versus 19+/-13 minutes) and x-ray exposure (20.8+/-18 versus 18+/-13 minutes) did not differ between the 8-mm-tip and the cooled-tip procedures. Number of applications (9.9+/-11 versus 18.6+/-15 minutes; P<0.0001) and x-ray exposure (11.7+/-11 versus 19.5+/-16 minutes, P=0.0001) differed significantly between patients with short and long CTIs. Patients with short and straight CTIs required 3 times fewer RFA applications and shorter x-ray exposure compared with other CTI morphologies (pouch-like recesses and concave characteristics).


CONCLUSIONS
The number of RF applications required for a complete isthmus block in long CTIs is not influenced by the choice between an 8-mm or cooled-tip catheter. Procedure parameters, however, are significantly influenced by CTI length and morphology. Pouch-like recesses and concave characteristics account for much longer ablation times at all CTI lengths.
Da Costa
Antoine
A
University Hospital Jean Monnet, Division of Cardiology, Saint-Etienne, France. dakosta@aol.com
Faure
Emmanuel
E
Thévenin
Jérôme
J
Messier
Marc
M
Bernard
Samuel
S
Abdel
Kihel
K
Robin
Christophe
C
Romeyer
Cécile
C
Isaaz
Karl
K
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001281:Atrial Fibrillation / Q000453:epidemiology / Q000517:prevention & control; D001282:Atrial Flutter / Q000473:pathology / Q000601:surgery*; D017115:Catheter Ablation / Q000295:instrumentation*; D002932:Cineangiography; D003080:Cold Temperature; D003287:Contrast Media; D004562:Electrocardiography; D005260:Female; D006325:Heart Atria / Q000000981:diagnostic imaging* / Q000473:pathology; D006801:Humans; D015993:Life Tables; D008297:Male; D008875:Middle Aged; D011446:Prospective Studies; D014261:Tricuspid Valve / Q000000981:diagnostic imaging* / Q000473:pathology; D014684:Venae Cavae / Q000000981:diagnostic imaging* / Q000473:pathology
D003287:Contrast Media