Intracardiac echocardiography

This article describes currently available intracardiac ultrasound (ICE) technology contrasting it with intravascular ultrasound (IVUS) highlighting their differences. Clinical applications in the electrophysiologic and cardiac catheterization laboratory are discussed and current limitations addressed. Intracardiac echocardiography (ICE) is possible because lower frequency transducers (in contrast to higher frequency IVUS devices) have been miniaturized and mounted onto catheters capable of percutaneous insertion into the heart. These lower frequency transducers are capable of enhanced tissue penetration, permitting high-resolution 2D "whole heart" imaging. Also, with the introduction of the newest phased array transducer, Doppler hemodynamic data in addition to high resolution imaging can also be obtained. ICE facilitates electrophysiologic procedures by guiding transseptal catheterization, enabling endocardial anatomy visualization and targeting of arrhythmogenic substrate, ensuring optimal ablation electrode/tissue contact and promptly diagnosing procedural complications. Promising non-electrophysiologic applications include guidance of percutaneous closure of septal defects, percutaneous mitral balloon valvuloplasty and complex cardiac biopsy. Current limitations include monoplanar imaging, narrow field of view, and relatively large size of the catheter. Intra-cardiac imaging is now a clinical tool and has the potential to play an important role in diagnostic and therapeutic interventional procedures. Further refinement and miniaturization of these transducers, through continued technological progress, will make way for primary operator controlled, integrated ultrasound-guided interventional devices.