Isolated Conduction Within the Left His-Purkenje System During Sinus Rhythm and Idiopathic Left Ventricle Tachycardia

Abstract

Electrophysiology study was performed after written informed consent and withdrawing antiarrhythmic drug for ≥5 half-lives. Diagnostic catheters, including 2 quadripolar catheters and 1 quadripolar or octapolar catheter (Biosense-Webster Inc, Diamond Bar, CA), were deployed to His-bundle position, right ventricular apex, and coronary sinus, respectively. A 4-mm, 4-pole cool saline-irrigated catheter (Navi-Star Thermo-Cool, Biosense-Webster Inc, Diamond Bar, CA) compatible with CARTO system (CARTO, Biosense-Webster Inc, Diamond Bar, CA) was introduced into left ventricle (LV) via retrograde approach for activation mapping, geometry reconstruction, © 2013 American Heart Association, Inc. Circ Arrhythm Electrophysiol

Change in QRS Morphology during Extrasystole Ablation: What is the Mechanism?

“…The Purkinje potentials (15-42 ms preceding the earliest QRS) or late diastolic potentials have been postulated as target points for ablation. 3,4 In our case, after the first application, an evident left axis deviation (−45°) was present in the sinus rhythm. Additionally, the VE changed to a narrower QRS morphology (115 ms) with incomplete RBBB and a normal frontal axis (54°; Fig.…”

“…A perfect pace map may be obtained along the fascicule from the true site of origin to the exit at the LV myocardium, assuming that a pure fascicular capture has been obtained. Moreover, the combination of these data with an activation mapping may not identify the target, but probably the ventricular output, which is usually 1–2 cm more distal . So, an application at this point may not stop the arrhythmia; however, it can cause a change in the ventricular output, as in our case, even demonstrating a left anterior hemiblock.…”

“…Fascicular anterior VTs involve the Purkinje system but are more proximal, so the QRS is less broad, as in our case (136 ms), with RBBB, a typical left posterior hemiblock, and an inferior axis. The Purkinje potentials (15–42 ms preceding the earliest QRS) or late diastolic potentials have been postulated as target points for ablation …”

“…During fascicular tachycardia/extrasystole, the isolated conduction remains. It seems that the earliest presystolic Purkinje potential identifies the target point for ablation, and the distal portion of the fascicule is only a bystander . The use of electroanatomical mapping potentially increases the accuracy to target most of the arrhythmic substrates including VE; nonetheless, in this entity the location of the target point with pace mapping is of limited value.…”

Macroreentrant Loop in Ventricular Tachycardia From the Left Posterior Fascicle

“…12 However, none of these studies have clearly defined the relationship between the ablation target and the mechanism of LPF-VT. In fact, based on our model of the LPF-VT circuit, the earliest Purkinje potential targeted by previous studies was the earliest P2 (the connection of P1 and P2).…”