Epicardial electroanatomical mapping for intraoperative evaluation of bilateral pulmonary vein isolation.
Eight patients (pts; 2 female, 58 +/- 12 yrs) with paroxysmal atrial fibrillation (AF) (duration 39 +/- 20 months) underwent AF surgery, with concomitant myocardial revascularization in 2 pts and myomectomy in 1 (HOCM). AF was idiopathic in the remaining 5 pts. AF surgery consisted of bilateral isolation of the pulmonary veins (PV) using radiofrequency (RF) energy applied epicardially by a heptapolar catheter (Thermaline) in 5 pts and by a new system (Atricure) in 3 pts. For the former, each set of 7 simultaneous applications aimed at a maximum duration of 2 + 2 min., preset temperature 80 degrees C and output 150 watts. With the new system, bipolar applications were carried out; energy delivery was controlled by impedance monitoring and applications were ended after abrupt, sustained elevation of impedance. Epicardial bipolar voltage mapping (CARTO) was performed before and after each RF procedure. Using the navigator catheter, points were recorded at the insertion of each PV and at the non-isolated left atrial posterior wall. The amplitude of the local electrograms (LE) was measured before and after RF applications. If the LE amplitude inside the isolated zone was not 0.1 mV and not reduced by > 80%, a second application was performed. A maximum of 2 epicardial applications were carried out in each pt and if the final result was unsatisfactory, further endocardial applications were performed.


RESULTS
Baseline LE amplitudes were > 1 mV in all cases. Successful isolation of right PVs was achieved in 7 pts, after one set of applications in 5 and a second set in 2. Left PV isolation required 2 sets of epicardial applications in all pts, being successful in only 2; 4 pts (one with associated myomectomy and 3 with idiopathic AF) received endocardial applications. Overall, bilateral PV isolation was achieved in 5 pts.


CONCLUSIONS
CARTO bipolar voltage mapping is a fast, simple means for evaluation of epicardial PV isolation.
Serviço de Cardiologia, Hospital de Santa Cruz, Av. Prof. Dr. Reinaldo dos Santos, 2975 Carnaxide. padragao@netcabo.pt
Pedro
P
Adragão
João Queirós
JQ
E Melo
Diogo
D
Cavaco
Carlos
C
Aguiar
José
J
Neves
Miguel
M
Abecasis
Teresa
T
Santiago
Dipali
D
Chotalal
Daniel
D
Bonhorst
Ricardo
R
Seabra-Gomes
D001281:Atrial Fibrillation / Q000601:surgery*; D006348:Cardiac Surgical Procedures; D004594:Electrophysiology; D005260:Female; D006801:Humans; D007432:Intraoperative Period; D008297:Male; D008875:Middle Aged; D010496:Pericardium / Q000473:pathology* / Q000503:physiopathology*; D011446:Prospective Studies; D011667:Pulmonary Veins / Q000601:surgery*