Introduction: Image integration has been used to good effect in electrophysiological (EP) procedures to aid in understanding the cardiac anatomy especially in complex cases. A computed tomography (CT) fusion tool has recently been developed (GE Healthcare Systems, Chicago, Illinois, USA). This new technology enables co-alignment of CT images with real-time 4D trans-oesophageal (TOE) images to allow for extended field-of-view over conventional echocardiography images for a better understanding of cardiac anatomy and tissue characterization. These features may potentially enable procedures to be performed in a more confident and safe manner. This technology has been trialed for use in structural cardiology cases, but its use in EP has not hitherto been described. We report the first worldwide use of the technology to guide transseptal puncture and locate the course of the coronary sinus (CS).
Methods: A 63-year-old man with ischemic heart disease and persistent atrial fibrillation (AF) and previous cryoballoon pulmonary vein isolation was listed for a redo ablation procedure including Vein of Marshall (VoM) ethanol ablation. Due to difficult transseptal puncture at his previous procedure we opted for a TOE-guided transseptal puncture with CT fusion. Cardiac CT images were acquired pre-procedure according to standard protocols. The images were pre-procedurally uploaded to the echo scanner and CT alignment was performed using anatomic markers. The images were fused with the live 4D echo images and used to guide the procedure.
Results: CT images revealed the presence of two conventional left-sided and three right-sided pulmonary veins. There was no left atrial appendage thrombus. The interatrial septum was found to be thickened (“double-barrel” septum) inferiorly. CT fusion images were used to locate the thinner part of the septum and angulate the needle and sheath more posteriorly with successful transseptal puncture using a SL1 sheath and BRK1 needle at first attempt (Figure 1A–C) The origin and course of the CS were located on the aligned CT images pre-procedurally. CT fusion was used to guide CS intubation with a steerable sheath and LIMA guide catheter (Figure D,E). A guidewire was then used to locate the ostium of the VoM branching more distally from the CS, and VoM ethanol ablation was performed as previously reported.
Conclusion: This is the first reported application of CT/TOE fusion to guide EP procedures, demonstrating its added value for procedural support and patient safety in complex cases. CT fusion is a valuable multimodality imaging tool in preprocedural planning and procedure guiding, and has the potential to aid with difficult cardiac anatomy, for example in patients with adult congenital heart disease. We intend to build a prospective registry of such cases.