Visualizing ablation gaps in vitro using a deflectable fiber optic endocardial visualization catheter

The efficacy of pulmonary vein isolation for the treatment of atrial fibrillation may be limited by the ability to make continuous and transmural lesions utilizing an ablation catheter. Gaps often persist between ablation lesions leading to failed electrical isolation and thus failed ablation. Recently, a deflectable fiberoptic endocardial visualization catheter has been introduced for use in imaging the coronary sinus using light in the visible spectrum. We utilize this catheter to visualize the endocardial surface and examine radiofrequency ablation lesions in porcine endocardium to determine the presence of gaps between radiofrequency lesions. Videos were taken of the lesions and shown to two readers who were asked to identify the gaps ranging from less than 0.1 mm-9.8 mm. Ninety-four lesion gaps were reviewed. The readers demonstrated a combined accuracy of 98.4% at identifying gaps. Gaps between ablation lesions can be accurately identified down to less than 1 mm distances in vitro using a direct visualization catheter. Further studies are warranted to confirm these finding in vivo.