Jan 1, 2022 · Postinfarction ventricular tachycardia (VT) caused by a reentrant circuit is an important clinical problem. Catheter ablation may not prevent VT because of difficulty in inducing and mapping all circuits. VT circuit properties, particularly the isthmus region as a target for ablation, are described.

Specifically, the aims of this study were to: 1) determine the ability of ACVM to identify zones of slow CV within the VT isthmus and delineate circuits during stable VT; 2) evaluate the utility of ACVM to identity areas of slowed CV in substrate analysis; and 3) assess and compare CV of putative VT isthmus and the underlying substrate with ...

VT isthmuses are complex structures, with multiple entrances, exits and dead ends of activation. The isthmus is frequently defined by regions of functional block and several VT circuits can be possible in a VT “critical zone”.

Aug 2, 2004 · Parts of VT reentry circuit isthmuses can be traced during sinus rhythm by combining both the QRS morphology and the S-QRS delay from pace mapping in anatomic maps. Ablation within these isthmuses abolishes VT that utilizes that isthmus.

Jul 24, 2013 · Isthmus 2, between the ventriculotomy and pulmonary annulus, was frequently described in the literature as a target for catheter ablation. 21 – 24 However, this isthmus was often absent secondary to a transannular incision or avoidance of RVOT incision altogether, and it is likely that with changes in surgical technique this isthmus will be ...

Oct 9, 2018 · Voltage within the ventricular tachycardia (VT) isthmus. Left and right upper, VT late after myocardial infarction. The isthmus is defined by a combination of lines complete block (black dots), with clear split signals (yellow arrows), and functional block (gray dots), with fractionated multicomponent electrograms (blue arrows).

Nov 1, 2022 · In the setting of structural heart disease, ventricular tachycardia (VT) is typically associated with a re-entrant mechanism. In patients with hemodynamically tolerated VTs, activation and entrainment mapping remain the gold standard for the identification of the critical parts of the circuit.

the circuit defines a cycle of VT. The isthmus, which is also known as the diastolic corridor or central common pathway, is a protected segment in the circuit where all loops rejoin, and ablation at this location has the best chance to disrupt the circuit. In order to …

Oct 28, 2013 · Most postinfarct ventricular tachycardias (VTs) are sustained by a reentrant mechanism. The “protected isthmus” of the reentrant circuit is critical for the maintenance of VTs and the target for catheter ablation.

Herein, we describe properties of reentrant VT circuits that may assist in elucidating the mechanisms of onset and maintenance, as well as a means to localize and delineate optimal catheter ablation targets. Keywords: Catheter ablation; Isthmus; Mapping; Reentrant circuit; Ventricular tachycardia. Copyright © 2021 Heart Rhythm Society.