Catheter Ablation of Coexistent Bundle Branch and Interfasdcular Reentrant Ventricular Tachycardias

Abstract

This report is of an unusual patient with coexistent bundle branch reentry and interfascicular reentry producing two different forms of sustained ventricular tachycardia. This is the first report of catheter ablation of the left posterior fascicle for elimination of conduction system reentry.

Mechanisms of Sustained Ventricular Tachycardia in Myotonic Dystrophy

“…Berger et al 25 reported on a patient with myotonic dystrophy, dilated cardiomyopathy, and ventricular tachycardia secondary to bundle-branch reentry. These authors attributed this mechanism to the dilated cardiomyopathy but pointed out that in their patient, myotonic dystrophy probably contributed to the mechanism through His-Purkinje system impairment.…”

Radiofrequency Catheter Ablation of an Incessant Ventricular Tachycardia Following Valve Surgery

“…1 A bundle branch reentrant tachycardia could use the left posterior fascicle in an antegrade direction with retrograde activation of the right bundle or the left anterior fascicle as it has been observed in left BBRT 7,8 and interfascicular reentrant tachycardia. 9 The retrograde reentry into the His-Purkinje system might alternatively be possible by a valve surgery induced nonphysiologic "connection" between ventricular myocardium and the His-Purkinje-system, e.g., at the level of the tricuspid annulus. To allow this type of reentrant circuit one had to postulate a surgery caused an "insulation" defect of the His-Purkinje-system.…”

Reinitiation of Ventricular Macroreentry within the His‐Purkinje System by Back‐Up Ventricular Pacing—A Mechanism of Ventricular Tachycardia Storm

“…Interfascicular tachycardia is another form of macroreentry within the His-Purkinje system, which usually proceeds in an anterograde direction over the left anterior fascicle and retrograde through the posterior fascicle. [4][5][6] In this case, the initial site of ventricular depolarization is at the distal end of the left anterior fascicle and the QRS morphology has a right bundle branch block (RBBB) and left posterior fascicular block (LPFB) pattern. Typically, conduction may occur in the opposite direction leading to a VT with RBBB and left anterior fascicular block (LAFB) pattern.…”

“…Ventricular depolarization begins at the distal end of the right bundle, and BBRT usually presents with a typical left bundle branch block (LBBB) pattern. Interfascicular tachycardia is another form of macroreentry within the His‐Purkinje system, which usually proceeds in an anterograde direction over the left anterior fascicle and retrograde through the posterior fascicle 4–6 . In this case, the initial site of ventricular depolarization is at the distal end of the left anterior fascicle and the QRS morphology has a right bundle branch block (RBBB) and left posterior fascicular block (LPFB) pattern.…”