LASER PHOTOABLATION OF EXPERIMENTAL POSTINFARCTION VENTRICULAR-TACHYCARDIA GUIDED BY 3-DIMENSIONAL ACTIVATION MAPPING

Background and Objective: The purpose of this study was to evaluate th e efficacy of epicardially delivered laser energy to ablate induced ve ntricular tachycardia in a post-infarction canine model. Study Design/ Materials and Methods: In 13 canines, the left anterior wall myocardia l infarction was created. Five days later, 240 plunged electrodes were inserted into the heart. Three-dimensional ventricular activation seq uences were analyzed on line by a computerized mapping system. Results : Sixteen sustained monomorphic ventricular tachycardias were reproduc ibly induced in 10 canines. Epicardially contacted Nd:YAG laser irradi ated the areas of the final pathway in macro-reentrant activation and the impulse origin in focal excitation. Linear photocoagulation lesion s (11-16 x 50-72 mm) were created. Seven macro-reentrant circuits and six of nine focal origins were eliminated (success rate 81%). Patholog y showed that laser photocoagulation involved all surviving subepicard ial and intramural fibers. Conclusion: Epicardially delivered laser en ergy in conjunction with electrical activation mapping has a high prob ability of ablating post-infarction ventricular tachycardia. (C) 1997 Wiley-Liss, Inc.