Intracardiac echocardiography during catheter-based procedures: ultrasound system, examination technique, and image presentation.

Abstract

A detailed understanding of the anatomic structures of both atria is mandatory for successful catheter-based interventional techniques. Some of the drawbacks of transthoracic and transesophageal echocardiography can be overcome by intracardiac echocardiography (ICE). We present our ICE experience based on 70 out of 186 patients who were included in a multicenter registry of transcatheter interatrial communication closures. The ultrasound catheter was a 9-Fr, 9 MHZ monoplane probe (Ultra ICE catheter) compatible with the motor drive unit and imaging console of the Clear View Ultra. Four slice selections in the axial plane and only one in the sagittal plane were needed in order to obtain a comprehensive guide to ICE interrogation. Their intracardiac ultrasound imaging presentation is an essential and nontrivial step. The anatomic coordinate system was maintained identical to a tomographic imaging plane as follows: Left/right and anterior/posterior in the axial planes and superior/inferior and anterior/posterior in the sagittal plane. In order to identify the imaging coordinates, two specific anatomic landmarks were used. The first one was the crista terminalis (at 10 o'clock) and the second one was the right atrial auricle (at 12 o'clock). Once the ultrasound images were orientated, their interpretation and spatial reconstruction were straightforward. In conclusion, a standardized ICE examination allows for a comprehensive evaluation of the right atrial anatomy and may be helpful in guiding therapeutic catheter-based interventions. The major clinical advantages of ICE include optimal contrast between soft-tissue structures, limited fluoroscopic exposure time, and good patient acceptance, thus avoiding general anesthesia.