CATHETER ABLATION OF COEXISTENT BUNDLE-BRANCH AND INTERFASCICULAR REENTRANT VENTRICULAR TACHYCARDIAS

Bundle Branch and Interfascicular Reentry. Introduction: Bundle branch reentry and interfascicular reentry are potential mechanisms of ventr icular tachycardia in the setting of a dilated cardiomyopathy. We repo rt a patient with myotonic dystrophy who presented with near syncope, in whom both of these mechanisms were present, leading to two differen t wide complex tachycardias. Methods and Results: Electrophysiologic s tudy demonstrated infra-Hisian conduction system disease and inducible bundle branch reentrant ventricular tachycardia. Catheter ablation of the right bundle eliminated bundle branch reentry. However, following this, the patient had inducible interfascicular reentry, which subseq uently occurred spontaneously while still hospitalized. Catheter ablat ion of the left posterior fascicle successfully eliminated this second tachycardia, and the patient has had no further arrhythmias. Conclusi ons: This report is of an unusual patient with coexistent bundle branc h reentry and interfascicular reentry producing two different forms of sustained ventricular tachycardia. This is the first report of cathet er ablation of the left posterior fascicle for elimination of conducti on system reentry.