Over the last several years, intracardiac echocardiography (ICE) has been employed successfully in guiding transcatheter device closure of a secundum atrial septal defect (ASD) or patent foramen ovale (PFO). Nothing is known regarding the use of ICE to guide catheter device closure of a perimembranous ventricular septal defect (PMVSD). Twelve patients (seven female/five male) who had a PMVSD (among them, three patients with associated atrial communications: two with an ASD and one with a PFO) underwent attempts at transcatheter device closure using the Amplatzer membranous VSD device of their defects, using sequential transesophageal echocardiography (TEE) and ICE guidance with general endotracheal anesthesia (five patients) and using ICE alone with conscious sedation (seven patients). The mean age of patients was 16.9 +/- 3.7, and their mean weight was 42.4 +/- 6.6. Their mean left ventricular end-diastolic dimension preclosure was 45.7 +/- 2.5. The Qp/Qs ratio ranged from 1.0 to 1.8:1. During the procedure, the ICE catheter was positioned in the right atrium (RA) in all 12 patients and the ICE catheter was advanced to the left atrium to obtain a view of the ventricular septum in 3. Both TEE and ICE provided similar anatomical views of the position of the PMVSD. Furthermore, the relationship of the defect to the aortic valve and tricuspid valves, the measured size of defect, and the guidance of various stages of device deployment were comparable by TEE and ICE. There were no complications encountered during or after closure. We conclude that ICE provides unique images of the PMVSD and measurements similar to those obtained by TEE. ICE potentially could replace TEE in most patients as a guiding imaging tool for PMVSD device closure, thus eliminating the need for general endotracheal anesthesia.