Deep myocardial ablation lesions can be created with a retractable needle-tipped catheter.
RF catheter ablation of ventricular tachycardia is sometimes limited by inadequate lesion depth. This study investigated the use of a retractable needle-tipped catheter to create deep RF lesions in vivo in porcine myocardium. An 8 Fr electrode catheter with an extendable 27-gauge needle at the tip was modified for RF ablation by embedding a thermocouple and attaching a pin connector. In three swine (32-58 kg) the left ventricle was entered via the femoral artery and endocardial contact was made. The needle was advanced 10 mm and 13 RF applications were made under a controlled temperature (90 degrees C x 120 s). Nine control lesions were made using a standard 4-mm tip catheter (60 degrees C x 120 s). The lesions were fixed, serially sectioned from the endocardium, digitally imaged, and quantified. Needle ablation lesions were deeper (10.15 +/- 0.77 vs 5.67 +/- 0.37 mm, P < 0.001) and more likely to be transmural (77 vs 11%, P = 0.008) than control lesions. The volume of control lesions, however, was larger (358.4 +/- 56.2 vs 174.7 +/- 18.6 mm(3), P = 0.002) due to a significantly larger cross-sectional area at the endocardium (0.548 +/- 0.04 vs 0.151 +/- 0.01 cm(2), P < 0.001). At depths > 6 mm, the needle electrode lesions had a greater cross-sectional area (0.136 +/- 0.01 vs 0.005 +/- 0.004 cm(2), P < 0.001). Catheter-based needle ablation is feasible and allows creation of deeper lesions that can be transmural. Although deep, the lesions had a small cross-sectional area such that precise targeting would be required for success.
Sapp
John Lewis
JL
Cardiovascular Division, Department of Internal Medicine, Brigham and Women's Hospital, Harvard Medical School, Boston, Massachusetts 02115, USA.
Cooper
Joshua Morrey
JM
Soejima
Kyoko
K
Sorrell
Timothy
T
Lopera
Gustavo
G
Satti
Srinivasa Dinakar
SD
Koplan
Bruce Andrew
BA
Epstein
Laurence Mark
LM
Edelman
Elazer
E
Rogers
Campbell
C
Stevenson
William Gregory
WG
D000818:Animals; D017115:Catheter Ablation / Q000295:instrumentation*; D004867:Equipment Design; D005240:Feasibility Studies; D008297:Male; D009206:Myocardium / Q000473:pathology*; D013552:Swine