Patients and Procedure Characteristics
Baseline demographics of the ten patients are shown in Table 1; patients had an average age of 65.6 ± 10.3 years and 60% were female. Single transseptal catheterization was performed in each patient guided by fluoroscopy and ICE. A powered transseptal needle (NRG®, Baylis Medical, Toronto, Canada) was used in nine patients and a powered 8.5 French guidewire (VersaCross®, Baylis Medical, Toronto, Canada) was used in the one patient with an atrial septal defect occluder in place. Pulmonary vein isolation was performed in eight patients who underwent catheter ablation for refractory atrial fibrillation. Cryoballoon ablation was performed in seven patients using the second-generation cryoballoon (Artic Front Pro™, Medtronic, Minneapolis, MN), and pulsed-field ablation (PFA) was performed in one patient (PulseSelect ™ PFA System, as part of the Pulsed AF pivotal clinical trial sponsored by Medtronic). In one patient who underwent CBA, additional left atrial posterior wall isolation was performed using radiofrequency ablation (RFA) with an open-irrigation ablation electrode. Left atrial appendage closure was performed in two patients using an FDA-approved plug-type device (Watchman FLX™, Boston Scientific, Malborough, MA). The ICE catheter was placed in the LA in two patients who underwent CBA and in two patients who underwent LAAC.
Diagnostic-quality 2D and 4D images of various cardiac structures, transseptal catheterization equipment, long guide sheaths, ablation tools, and closure devices were acquired with the ICE catheter positioned in the RA, LA, PV, coronary sinus, right ventricle, and pulmonary artery. Operators noted that the 4D ICE catheter was easy to advance into the RA and LA and easy to manipulate to acquire images. Compared to other commonly used, commercially available 2D ICE catheters, the 4D ICE catheter was notably more flexible at the segment just proximal to the distal imaging portion. This flexibility enabled the catheter to be placed in alternate positions including the coronary sinus with little risk of cardiac perforation. Fluoroscopy could be used to discern the imaging direction based on the appearance of the tip of the ICE catheter. The standard 2D, X-plane, 3D, and 4D ICE images were of high-quality and were able to guide the EP procedures. A combination of 2D imaging, X-plane imaging, and 3D imaging was used for all cases. There were no complications related to the use of the catheter.