Confirmation of cardiac radiofrequency ablation treatment using intra-procedure acoustic radiation force impulse imaging

Recurrence of atrial fibrillation after transcatheter ablation (TCA) is common because there is no imaging modality that can visually confirm the presence of radiofrequency ablation (RFA) lesions. We have previously shown that acoustic radiation force impulse (ARFI) imaging can visualize the relative tissue stiffness changes caused by RFA. The objective of this study was to determine if intra-procedurally acquired ARFI images could identify RFA lesions. In 8 canines, an integrated ARFI imaging-electroanatomical mapping (EAM) system was used to map the geometry of the right atrium and acquire ARFI images along an inter-caval line before and after RFA. RF-energy delivery sites were marked in the EAM geometry to guide the ARFI imaging plane to RFA lesion locations. The ARFI images were randomized and three separate reviewers read the images for the presence of RFA lesion. The majority assessment for each ARFI image was counted in a 2 × 2 contingency table according to the presence/absence of a RFA treatment marker in the EAM geometry at the ARFI imaging plane. EAM guided intra-procedure ARFI imaging of RFA treatment sites. Reviewers of the ARFI images identified RFA lesion with a high sensitivity (96.3%) and specificity (93.2%). Incorporating an integrated ARFI imaging-EAM system into TCA for the visualization of RFA lesions could potentially improve the procedure efficacy.