HR: New 3D imaging tool is efficacious as atrial fibrillation ablation guide
Three-dimensional rotational atriography overlay is a new imaging method with reduced radiation exposure that may replace pre-procedural CT scans for catheter navigation and atrial fibrillation ablation, according to a study in the February issue of HeartRhythm.

According to the authors, 3D rotational atriography (3DATG) was developed to supplement 2D fluoroscopy with 3D volume reconstruction of the left atrium, pulmonary veins and other structures. Until recently, 3DATG images could only be viewed separately and were not suitable to directly guide atrial fibrillation ablation.

Jonathan H. Li, MD, from Caritas St. Elizabeth's Medical Center, Tufts University School of Medicine in Boston, and colleagues undertook the study to evaluate the feasibility and accuracy of intraprocedural 3DATG.

The researchers found that the majority (93 percent) of 3DATG image reconstructions were useful for guidance of catheter ablation. Nearly all pulmonary veins (94 percent), left atrium appendage (89 percent) and esophagus (100 percent) were successfully segmented.

Measured pulmonary vein ostial diameters compared using 3DATG and CT showed close concordance. The authors wrote that "registration and re-registration of 3DATG overlay image was easily achieved with thoracic landmarks and validated by catheter placement demonstrating minimal discrepancy." They found that the endoscopic views allowed for improved visualization of ostial position, dimensions and navigation within the antrum. Lesion tagging on 3DATG overlay enhanced ablation guidance.

The investigators also said that "radiation exposure with 3DATG was significantly reduced compared with preprocedural CT scan" (2.1 mSv vs. 13.8 mSv).

Li and colleagues concluded that the intraprocedural 3DATG imaging during atrial fibrillation ablation with online segmentation and superimposition on live fluoroscopy is feasible. Overlay provides valuable and accurate information on 3D surface outline and endoscopic pulmonary vein location, according to the authors.