TRANSCUTANEOUS MULTIELECTRODE BASKET CATHETER FOR ENDOCARDIAL MAPPINGAND ABLATION OF VENTRICULAR-TACHYCARDIA IN THE PIG

Background Endocardial mapping using standard electrode catheters is o ften technically limited in ventricular tachycardia and constitutes a major obstacle to successful ablation. We wished to examine the utilit y of a basket-shaped multielectrode mapping catheter (MMC) in the mapp ing and ablation of ventricular tachycardia. Methods and Results This study of sustained monomorphic ventricular tachycardia (SMVT) was cond ucted in two phases in the postinfarction pig model, In the first phas e, the utility of the MMC in providing adequate localization of potent ial ablation site(s) of SMVT by different techniques (presystolic pote ntials, pace mapping, and concealed entrainment) was assessed in 21 pi gs. In the second phase, ablation of induced SMVT was attempted in 10 pigs. Mapping of SMVT was performed after percutaneous introduction of the MMC to the LV. Comprehensive mapping was performed in 90 episodes of SMVT and required 2.0 to 25 seconds. Diastolic potentials were rec orded during 86 episodes; good or identical pace maps (greater than or equal to 9 of 12 paced surface ECG leads identical to ventricular tac hycardia surface ECG leads) were obtained in 25 of 31 maps, and entrai nment was achieved during 28 of 42 SMVTs. In 10 pigs, 10 SMVTs were re corded at least twice and were considered for radiofrequency ablation. An 8-mm tip ablation catheter was advanced to potential ablation site s with a specially designed ''homing'' device, requiring a median time of 120 seconds. In these 10 pigs, either identical pace map (greater than or equal to 11 of 12, 6 SMVTs) or concealed entrainment (4 SMVTs) guided the ablation procedure. After ablation, 8 of 10 SMVTs were ren dered noninducible, while 2 pigs died during energy application of deg eneration of SMVT to ventricular fibrillation. Conclusions The MMC all ows rapid, comprehensive, and reliable endocardial mapping during SMVT s, which facilitates successful ablation in the porcine post-myocardia l infarction model.