Intracardiac Echocardiography to Assist Anatomical Isthmus Ablation in Repaired Tetralogy of Fallot Patients With Ventricular Tachycardia: Technique and Outcomes.

BACKGROUND

Successful catheter ablation of ventricular tachycardia (VT) in repaired tetralogy of Fallot (TOF) can be achieved by targeting 1 or more anatomical isthmuses. However, significant interindividual variability in the size and location of surgical patches means careful mapping is required to design ablation lines to block the isthmus. Intracardiac echocardiography (ICE) may assist ablation by accurate identification of individual TOF anatomy.

OBJECTIVES

The authors hypothesized ICE-guided VT ablation improved isthmus recognition, ablation, and procedural outcomes.

METHODS

Retrospective study of adults with repaired TOF undergoing VT ablation between January 1, 2017 and December 31, 2022. ICE integration was compared to a strategy using electroanatomical mapping only to identify anatomic boundaries. All cases underwent ablation and had proven isthmus block as the procedural endpoint.

RESULTS

Twenty-three patients (age 47 ± 14 years; 61% male) underwent 27 VT ablations (ICE: 16/27 [59%]; no ICE: 11/27 [41%]). ICE improved the ability to localize and ablate the anatomical isthmus (ICE: 13/15 [87%] vs no ICE: 4/11 [36%];  = 0.014); however, there was no difference in long-term freedom from VT (ICE: 9/12 [75%] vs no ICE: 8/11 [73%];  = 0.901). ICE had no impact on procedural times (ICE: 173 ± 48 minutes vs no ICE: 157 ± 47 minutes;  = 0.399), fluoroscopy time (ICE: 30 ± 16 minutes vs no ICE: 29 ± 10 minutes;  = 0.864), or major complications (ICE: 1/16 [6%] vs no ICE 0/11;  = 1.000).

CONCLUSIONS

ICE improves ablation of the anatomical isthmus for sustaining VT in patients with repaired TOF by demonstrating the individual anatomy but does not improve long-term outcomes.