Determination of left atrium volume by fast anatomical mapping and intracardiac echocardiography. The contribution of respiratory gating

Background: The anatomical reconstruction of the left atrium (LA) and pulmonary veins with fast anatomical mapping (FAM) and intracardiac echocardiography (ICE) using the Carto 3 system (Biosense Webster, Inc) provides real-time guidance to catheter manipulation during ablation of atrial fibrillation (AF). The present study compared real-time LA volume reconstruction using FAM and ICE. In addition, the contribution of respiratory gating was assessed.

Methods: LA reconstruction was created using FAM and ICE in 60 consecutive patients (mean age 63 ± 9 years; 38 males) undergoing AF ablation. In the first 30 patients, FAM and ICE were performed without respiratory gating. In the last 30 patients, FAM and ICE were performed with respiratory gating.

Results: LA volumes determined by FAM were larger than those obtained with ICE in the absence of respiratory gating (n = 30; 129.5 ± 44 vs 110 ± 39.7 cm³; p = 0.001). However, respiratory gating reduced LA volume determined with FAM by 17.7 ± 6.6 % resulting in similar LA volumes to those obtained using ICE [n = 30; 100 ± 29.7 (61–154) vs 101.53 ± 40.1 (56–212) cm³, p = 0.7, NS].

Conclusions: In the absence of respiratory gating, LA volumes determined by FAM are larger than those obtained with ICE. In contrast, with the addition of respiratory gating, both FAM and ICE provide similar real-time LA volumes.