MAPPING TECHNIQUES AND CATHETER ABLATION OF VENTRICULAR-TACHYCARDIA DUE TO CORONARY-ARTERY DISEASE

In contrast to the high success rates for catheter ablation of focal v entricular tachycardia, radiofrequency ablation for ventricular tachyc ardia due to coronary artery disease has met with limited to variable success. In performing catheter ablation for ventricular tachycardia d ue to coronary disease, mapping techniques used to locate the isthmus of the reentrant circuit are crucial. Appropriate use of mapping techn iques determines the success rate of the procedure. We classify differ ent methods of mapping into indirect and direct. The indirect methods include analysis of the 12-lead electrocardiogram, endocardial pace-ma pping, and analysis of electrograms recorded from different parts of t he heart during sinus rhythm. The direct methods include activation se quence mapping and entrainment mapping. The direct methods are more im portant in evaluating ventricular tachycardia due to coronary disease, While using the technique of entrainment mapping, three criteria are important: a) entrainment with concealed fusion; b) post pacing interv al within or less than 10 ms of tachycardia cycle length; c) stimulus- to-QRS interval should equal electrogram-to-QRS interval, A high succe ss rate in terminating the tachycardia is seen if these criteria are m et.