Protocol for ICE/IVUS imaging of the PVs
As part of the trial, ultrasound imaging of the junctions between LA and pulmonary veins (PVs) was performed with either ICE or IVUS as per operator’s discretion.
For ICE imaging, a 9F catheter with a 9 MHz rotational transducer providing a maximal radial depth of 50 mm (Ultra ICE, Boston Scientific) was used. For IVUS imaging, a 20 MHz digital probe with maximum ultrasonic detection depth of 24 mm (Visions PV .018, Volcano, San Diego, CA) was chosen and used mounted on a guidewire (0.014-in percutaneous transluminal coronary angioplasty guidewire) as per manufacture instructions.
The ultrasound-imaging probe was introduced into the LA via the trans-septal access and advanced under fluoroscopic guidance distally into each pulmonary vein (PV) with the aid of a long steerable sheath. Images were recorded during slow manual pullback of the probe from each vein into the LA body. Each PV was imaged twice, before and after ablation.