Technique and results of linear ablation at the mitral isthmus.
BACKGROUND
This prospective clinical study evaluates the feasibility and efficacy of combined linear mitral isthmus ablation and pulmonary vein (PV) isolation in patients with paroxysmal atrial fibrillation (AF).


RESULTS
One hundred consecutive patients (13 women; age 55+/-10 years) with drug-refractory, symptomatic paroxysmal AF underwent PV isolation and linear ablation of the cavotricuspid isthmus and the mitral isthmus (lateral mitral annulus to the left inferior PV). They were compared with 100 consecutive patients (14 women; age, 52+/-10 years) undergoing PV isolation and cavotricuspid ablation without mitral isthmus ablation. Bidirectional mitral isthmus block was confirmed by demonstrating (1) a parallel corridor of double potentials during coronary sinus (CS) pacing, (2) an activation detour by pacing either side of the line, and (3) differential pacing techniques. Isolation of all PVs and cavotricuspid isthmus ablation were performed successfully in all. Mitral isthmus block was achieved in 92 patients after 20+/-10 minutes of endocardial radiofrequency application and an additional 5+/-4 minutes of epicardial radiofrequency application from within the CS in 68, resulting in a conduction delay of 151+/-26 ms during CS pacing. Thirty-two patients with mitral isthmus ablation compared with 49 without had recurrent atrial arrhythmia (P=0.02) requiring further ablation. At 1 year after the last procedure, 87 patients with mitral isthmus ablation and 69 without (P=0.002) were arrhythmia free without antiarrhythmic drugs, mitral isthmus ablation being the only factor associated with long-term success (RR for AF recurrence, 0.2; CI, 0.1 to 0.4; P<0.001).


CONCLUSIONS
Catheter ablation of the mitral isthmus results consistently in demonstrable conduction block and is associated with a high cure rate for paroxysmal AF.
Jaïs
Pierre
P
Hôpital Haut-Lévêque, Université Bordeaux II Victor Segalen, 33604 Bordeaux-Pessac, France. pierre.jais@chu-bordeaux.fr
Hocini
Mélèze
M
Hsu
Li-Fern
LF
Sanders
Prashanthan
P
Scavee
Christophe
C
Weerasooriya
Rukshen
R
Macle
Laurent
L
Raybaud
Florence
F
Garrigue
Stéphane
S
Shah
Dipen C
DC
Le Metayer
Philippe
P
Clémenty
Jacques
J
Haïssaguerre
Michel
M
D000368:Aged; D000925:Anticoagulants / Q000627:therapeutic use; D001281:Atrial Fibrillation / Q000601:surgery*; D001282:Atrial Flutter / Q000601:surgery; D017115:Catheter Ablation / Q000379:methods*; D004452:Echocardiography; D005240:Feasibility Studies; D005260:Female; D005500:Follow-Up Studies; D006493:Heparin / Q000627:therapeutic use; D006801:Humans; D008297:Male; D008875:Middle Aged; D008943:Mitral Valve / Q000601:surgery*; D011182:Postoperative Care; D011300:Preoperative Care; D016016:Proportional Hazards Models; D011446:Prospective Studies; D011667:Pulmonary Veins / Q000601:surgery*; D012008:Recurrence; D016896:Treatment Outcome
D000925:Anticoagulants; D006493:Heparin