Background: Intracardiac echocardiography (ICE), the method which uses an ultrasound transducer at the tip of a precutaneouosly placed catheter, recently has been introduced for visualization of the intracardiac structures. ICE has been demonstrated to be useful for closure interatrial septum defects and in interventional electrophysiology. This paper describes the use of ICE during implantation of biventricular pacing system for coronary sinus lead placement. Case Report: 60-year-old man with dilated cardiomyopathy and persistently symptomatic heart failure despite medical therapy was referred for implantation of CRT system. With the use of fluoroscopy, it was not possible to localize the coronary sinus ostium (CSO) necessary for left ventricle lead implantation. ICE was used as a method of CSO localization and for directing coronary sinus lead positioning. Phased-array ICE head was introduced to right atrium via venous system. CSO was detected and the lead was inserted into coronary vein system and finally into posterolateral branch. Conclusions: ICE is a valuable instrument for directing coronary sinus lead placement.

Keywords: intracardiac echocardiography, biventricular pacing, Electrophysiology, lead placement