Multidetector 16-slice CT scan evaluation of cavotricuspid isthmus anatomy before radiofrequency ablation.
BACKGROUND
The anatomy of the cavotricuspid isthmus (CTI) is an important determinant of the ease of radiofrequency ablation. We evaluated the anatomy of the region with a multidetector 16-slice computed tomography (CT) scan and correlated this with subsequent procedural difficulty.


METHODS
Twenty-nine patients (mean age 64 +/- 15 years) with typical atrial flutter or paroxysmal atrial fibrillation underwent ablation of the CTI. A multidetector 16-slice CT scan with contrast injection was performed in all before the procedure.


RESULTS
The CTI showed marked variability as evidenced by the following measurements: length (8.2 to 32.2 mm), width (26 to 56.5 mm), depth (0 to 11 mm), thickness (0.2 to 7.5 mm), the angle between the inferior vena cava and the CTI (59.9 to 129.5 degrees ), and the length of the Eustachian valve (4.8 to 26.1 mm) present in 72% of patients. The appearance of the CTI was classified as follows into three categories: concave (72%), flat (17%), or with a sub-Eustachian recess (28%). Procedures were classified as difficult in case of failure to achieve bidirectional block or if radiofrequency duration was greater than 99% confidence interval. In the multivariate analysis, a significant correlation was present between the thickness of the CTI and procedural difficulty (p = 0.0005).


CONCLUSIONS
The multidetector 16-slice CT scan with contrast injection accurately evaluates the anatomy of the CTI. The only independent anatomic parameter that predicts a more difficult procedure is the thickness of the CTI.
Knecht
Sébastien
S
Department of Cardiology, CHU Brugmann, Place Van Gehuchten 4, 1020, Brussel, Belgium. sebastien.knecht@chu-brugmann.be
Castro-Rodriguez
José
J
Verbeet
Thierry
T
Damry
Nasroola
N
Morissens
Marielle
M
Tran-Ngoc
Emmanuel
E
Peperstraete
Béatrice
B
Tatnga
Valentin
V
Elkholti
Merieme
M
Decoodt
Pierre
P
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001281:Atrial Fibrillation / Q000000981:diagnostic imaging* / Q000601:surgery*; D001282:Atrial Flutter / Q000000981:diagnostic imaging* / Q000601:surgery*; D017115:Catheter Ablation / Q000379:methods*; D054326:Coronary Sinus / Q000000981:diagnostic imaging* / Q000601:surgery; D006329:Heart Conduction System / Q000000981:diagnostic imaging / Q000601:surgery; D006801:Humans; D008297:Male; D008875:Middle Aged; D018579:Patient Selection; D011300:Preoperative Care / Q000379:methods; D011379:Prognosis; D025321:Surgery, Computer-Assisted / Q000379:methods; D014057:Tomography, X-Ray Computed / Q000295:instrumentation / Q000379:methods; D016896:Treatment Outcome; D014261:Tricuspid Valve / Q000000981:diagnostic imaging* / Q000601:surgery