Catheter Ablation of Ventricular Tachycardia After Repair of Congenital Heart Disease

Abstract

Background— Catheter ablation of ventricular tachycardia (VT) after repair of congenital heart disease can be difficult because of nonmappable VTs and complex anatomy. Insights into the relation between anatomic isthmuses identified by delineating unexcitable tissue using substrate mapping techniques and critical reentry circuit isthmuses might facilitate ablation. Methods and Results— Sinus rhythm voltage mapping of the right ventricle was performed in 11 patients with sustained VT after repair of congenital heart disease. Unexcitable tissue from patch material, valve annulus, or dense fibrosis, identified from bipolar voltage (<0.5 mV) and pacing threshold (>10 mA), was defined as an anatomic isthmus boundary bordering 4 isthmuses between (1) the tricuspid annulus and scar/patch in the anterior right ventricular outflow, (2) the pulmonary annulus and right ventricular free wall scar/patch, (3) the pulmonary annulus and septal scar/patch, and (4) the septal scar/patch and tricuspid annulus. The reentry circuit isthmuses of all induced 15 VTs (mean cycle length, 276±78 ms; 73% poorly tolerated), identified by activation, entrainment, and/or pace mapping, were located in an anatomic isthmus (11 of 15 VTs in anatomic isthmus 1). Transecting the anatomic isthmuses by ablation lesions abolished all VTs. During 30.4±29.3 months of follow-up, 91% of patients remained free of VT. Conclusions— Reentry circuit isthmuses in VT late after repair of congenital heart disease are located within anatomically defined isthmuses bordered by unexcitable tissue. The boundaries can be identified with 3-dimensional substrate mapping and connected by ablation lines during sinus rhythm. These findings should facilitate catheter and surgical ablation of stable and unstable VTs.

2015 ESC Guidelines for the management of patients with ventricular arrhythmias and the prevention of sudden cardiac death

“…Programowana stymulacja komór może być przydatna w celu identyfikacji pacjentów zagrożonych wystąpieniem SCD. Ablację przezcewnikową i metody chirurgiczne należy traktować jako leczenie alternatywne lub uzupełniające w stosunku do ICD u pacjentów z nawracającym utrwalonym VT po chirurgicznej naprawie wrodzonej wady serca [492].…”

Long-Term Efficacy of Implantable Cardioverter Defibrillator in Repaired Tetralogy of Fallot ― Role of Anti-tachycardia Pacing ―

“…The electrophysiological mechanism responsible for VT after surgically repaired TOF is typically a macro reentrant RV circuit within the RV around scar tissue or prosthetic materials used during surgical repair. 2,14, 15 Theoretically, any re-entrant VT can be terminated by a critically timed pacing stimulus that depolarizes the excitation gap. The duration of the excitation gap and the conduction time from the pacing stimulus site to the re-entrant circuit are the main factors influencing penetration of the excitation gap and termination of the arrhythmia.…”

Late arrhythmia in patients with repaired tetralogy of Fallot: who is at risk?

“…In rTOF patients, the macro-reentry type circuits situate mainly in the anatomic isthmuses, namely between RVOT/adjacent RV scar and tricuspid annulus or between PV and septal scar, surrounded by unexcitable tissue [74]. The success rate for treating VTs in rTOF patients by ablation varies from 50% to 91% according to the studies using electroanatomic substrate-based mapping approach [74,75].…”

“…The success rate for treating VTs in rTOF patients by ablation varies from 50% to 91% according to the studies using electroanatomic substrate-based mapping approach [74,75]. Described VT recurrence rates remain high (up to 20%) in turn hindering wider use of this treatment strategy in patients with rTOF [76,77].…”