Open-heart endocardial radiofrequency ablation: an alternative to incisions in Maze surgery.
BACKGROUND
Radiofrequency (RF) ablation produces transmural atrial lesions in vitro, and may provide advantages over incisions currently used in maze surgery. This study examines the feasibility, safety, and efficacy of open-heart endocardial RF ablation.


METHODS
Eighteen sheep (42.8 +/- 4.4 kg, age < 2 years) underwent left thoracotomy with placement of pacing leads on a pulmonary vein and the left atrial dome. On cardiopulmonary bypass, lesions were made using incision and suture or a novel RF ablation device in three sites: PVC = circle excluding pulmonary veins, IAB = line across the interatrial bundle, SVC = line from the superior to the inferior vena cava. Pacing across the PVC lesion was attempted to assess the completeness of each lesion. Preselected animals (incision n = 4, RF n = 5) were recovered and pacing attempts were repeated at 1 month. After sacrifice, hearts were sectioned and measured for lesion size and completeness.


RESULTS
RF ablation lesions took less time to create (total bypass time: RF 51.8 min vs incision 106 min, P < 0.001). No evidence of thromboembolism, atrial rupture, or coronary sinus thrombosis was seen. All PVC lesions were complete as demonstrated by the inability to pace across them. Stained sections demonstrated that acutely studied incision lesions were thinner than RF lesions; however, all lesions were transmural and similar in width at 1 month.


CONCLUSIONS
RF ablation consistently created transmural lesions more quickly than the incision and suture method and without additional complications. Endocardial RF ablation appears to be a simple and effective alternative to surgical incisions during open-heart atrial Maze procedures.
Caccitolo
J A
JA
Cardiac Surgery Research Center, Section of Cardiovascular Surgery, Mayo Clinic and Mayo Foundation, 200 First Street SW, Rochester, Minnesota 55905, USA.
Stulak
J M
JM
Schaff
H V
HV
Francischelli
D
D
Jensen
D N
DN
Mehra
R
R
D000818:Animals; D001281:Atrial Fibrillation / Q000601:surgery*; D017115:Catheter Ablation / Q000009:adverse effects / Q000379:methods*; D004699:Endocardium / Q000601:surgery; D005240:Feasibility Studies; D008297:Male; D012756:Sheep; D013997:Time Factors