Abstract 11773: Anatomical Characteristics of Mitral Isthmus Requiring Ablation inside the Coronary Sinus for Creation of Complete Linear Block in Patients with Atrial Fibrillation
Introduction: Creating a block line at the mitral isthmus (MI) is associated with a favorable outcome of catheter ablation for atrial fibrillation. However, radiofrequency energy delivery inside the coronary sinus (CS) is often required to achieve complete linear block. The purpose of this study was to elucidate the morphologic characteristics of the MI which may need ablating inside the CS.
Method: Eighty consecutive patients (mean age 63 ± 11, 64 male [80%], 44 persistent AF [55%]) who underwent the first linear ablation at the MI during catheter ablation for AF/AT were enrolled in the study. All patients underwent 64-slice MDCT scanning prior to the procedure and its anatomical features of the MI were analyzed.
Result: Complete MI block could not be achieved in 10 patients (12%) even though adding RF application in the CS (Group F). Among the remaining 70 (88%) patients who accomplished complete mitral isthmus block, 39 (55%) patients required radiofrequency ablation inside the CS (Group CS), and RF application was not required in the other 31 (45%) patients (Group Non-CS). There were no significant differences in patient characteristics and echocardiographic parameters including age, gender, type and duration of AF, left atrial diameter and ejection fraction. Further, there were no significant differences in the MI length, isthmus depth, CS diameter, CS cross-sectional area, and the distance between the CS and the MI. However, group CS and group F patients were more likely to have interposed circumflex artery between the CS and the MI (Group F: 6[60%], Group CS: 16[41%]), compared to Group Non-CS patients (5 [16%] P=0.02). The total amount of RF application in the CS was significantly greater in Group CS than Group F.
Conclusion: Patients in whom circumflex artery exists between the CS and the MI is more likely to require the radiofrequency ablation inside the CS. Larger total amount of RF application is often necessary for successful ablation in such patients. To confirm the anatomical location of the circumflex artery prior to the ablation provides us a useful information to decide delivering radiofrequency energy in the CS.
- © 2012 by American Heart Association, Inc.