Radiofrequency Catheter Ablation of Left Ventricular Outflow Tract Tachycardia:

Abstract

Idiopathic ventricular tachycardia (VT) originating from the left ventricular outflow tract (LVOT) is rare. We report two patients whose QRS configuration during VT commonly showed an inferior axis and monophasic R waves in all the precordial leads. The mechanism of these VTs appeared to be triggered activity. From mapping and ablation, the origin of these VTs was determined to be in the most posterior LVOT, corresponding to the aortomitral continuity (left fibrous trigone).

Heart Rate Variability Analysis of Patients With Idiopathic Left Ventricular Outflow Tract Tachycardia

“…1 In brief, the duration and the rate of the induced LVOT tachycardia was proportional whereas the coupling interval of the first beat of LVOT tachycardia was inversely proportional to the rapid high atrial or ventricular stimulation rate. These electrophysiological findings indicate overdrive acceleration rather than overdrive suppression as a causative mechanism of LVOT tachycardia.…”

“…previously 1 were enrolled in this study. Briefly, in the first case, the 59-year-old male patient's 12-lead ECG showed ventricular bigemy.…”

Catheter Ablation of Ventricular Tachycardia - Long-Term Results

“…Recent experience shows rather less successful results which may reflect indications in wider spectrum of idiopathic VT foci originating also in the left ventricular outflow tract as well as deep intramyocardial or epicardial foci in the outflow tract. Moreover, occassional VTs were described to arise from the sinuses of Valsalva 22,23 . These arrhythmogenic foci may not be accessible to conventional ablation therapy or are not approached by radiofrequency current for the risk of coronary artery damage.…”

“…In patients with hemodynamically unstable VT that cannot be mapped during the VT several ablation strategies are under developement (unpublished data) usually employing electroanatomical mapping with Carto system (Cordis-Biosense) which creates three-dimensional color map of the electrical activation sequence in the heart chambers 22 . These strategies use voltage mapping to identify scar, normal myocardium and abnormal tissue on the scar edge and try to transect this abnormal scar with radiofrequency current to interrupt possible reentry circuits.…”

Radiofrequency Catheter Ablation of Ventricular Tachycardia from the Anterobasal Left Ventricle.

“…30,31) Recently, Shimoike, et al reported two cases of successful ablation of LV outflow VTs from an endocardial site. 32) However, this site (left fibrous trigone) plays an important role in bridging aortic and mitral valve annuli. RF delivery in this area has potential risks of regurgitation, dysfunction, and perforation of both valves.…”