Real-time integration of 2D intracardiac echocardiography and 3D electroanatomical mapping to guide ventricular tachycardia ablation

Abstract

Background: Ablation of left ventricular tachycardia (LV VT) involves point-by-point reconstruction of the three-dimensional (3D) virtual anatomy. It is time consuming and requires substantial fluoroscopy exposure. Two-dimensional (2D) intracardiac echocardiography (ICE) affords real-time imaging of the cardiac structures.

Objective: This study sought to evaluate a mapping system integrating ICE with 3D mapping to guide VT ablation.

Methods: Seventeen patients (16 men, 62 +/- 11 years, LV ejection fraction 40% +/- 15%) had ablation of nonidiopathic VT guided using a system integrating 3D mapping and ICE. ICE probe with a location sensor tracked by the mapping system was positioned in the right heart. Endocardial contours traced on gated images of the LV were used to generate a registered 3D map. Regional wall motion abnormalities (WMA) were tagged.

Results: 3D maps were created in 26 +/- 8 min, before entering the LV and without fluoroscopy. Maps were built from 23 +/- 7 contours. Regional WMA corresponded to low bipolar voltage (<0.5 mV). Procedure time was 240 +/- 77 min, with fluoroscopy time of 25 +/- 12 min. LV volume by ICE was 172 +/- 119 cm(3) versus 164 +/- 112 cm(3) for the point-by-point maps (P = .5). Scar area by ICE was 33 +/- 32 cm(2) versus 36 +/- 33 cm(2) for voltage mapping (P = .4). At 5 +/- 4 months, 12 patients (71%) were free of VT.

Conclusion: A system combining 2D ICE and 3D mapping can reconstruct a 3D shell of the LV, including a substrate map based on regional WMA without the need to enter the LV. VT ablation guided using this approach is safe and effective.