PERCUTANEOUS MULTIELECTRODE ENDOCARDIAL MAPPING DURING VENTRICULAR-TACHYCARDIA IN THE SWINE MODEL

Background Identification of critical areas within the ventricular tac hycardia circuit is a prerequisite for catheter ablation. Currently, m apping during ventricular tachycardia, usually performed with standard catheters, is difficult and time-consuming and can be used only in pa tients with hemodynamically stable tachycardia. Methods and Results A total of 43 pigs underwent closed-chest induction of myocardial infarc tion. A basket-shaped catheter carrying 64 electrodes was deployed in the left ventricle during normal sinus rhythm. Unipolar pacing at 3 mA was successful in 78% of the basket catheter electrodes, demonstratin g good electrode-tissue contact. Hemodynamic and echocardiographic mea surements did not reveal any significant interference with myocardial or valvular function during or after catheter deployment. One hundred eighteen episodes of monomorphic ventricular tachycardia were induced 28 pigs through right ventricular stimulation, 81 of which were mapped and analyzed. Ventricular tachycardia mapping was rapid, requiring on ly several beats and <10 seconds to complete. Presystolic potentials, a possible target for ablation, were identified in 58% of the tachycar dia episodes mapped. Pathological examination revealed only minor valv ular and endocardial catheter-induced lesions immediately after mappin g and none a month later. Conclusions The multielectrode catheter enab les rapid and safe percutaneous endocardial mapping of ventricular tac hycardia in the swine model. Exploration of the clinical potential of the multielectrode catheter seems warranted.