The purpose of this study was to assess the safety and feasibility of percutaneous interventional closure of patent foramen ovale (PFO) with or without atrial septal aneurysm (ASA) in symptomatic patients. Between June 1999 and June 2002, we performed transcatheter closure of PFO in 256 consecutive symptomatic patients (female/male = 1.45; mean age 48 +/- 16 years; range 14-75): ischemic stroke (n = 101), transient ischemic attack (n = 144), peripheral and coronary arterial embolism (n = 17); multiple events (n = 23); platypnea-orthodeoxia syndrome (n = 2); refractory hypoxemia (n = 1); and migraine aura (n = 27). The implanted devices were an Amplatzer PFO Occluder (n = 248), a Gore-HELEX Septal Occluder (n = 4), and PFO STAR (n = 4). Most procedures (n = 176.69%) were done under two-dimensional intracardiac echocardiography (ICE) guidance alone; in the last 30 patients, 3D/4D ICE reconstruction (TomTec Imaging Systems) 6mbH was obtained. In 30 cases, ICE and contrast enhanced-TCD have been used simultaneously in the catheterization laboratory. The devices were placed correctly in all patients. Mean fluoroscopy time was 9.45 +/- 5 minutes (range = 2.5-35 minutes); mean procedural time was 57 +/- 21 minutes (range = 15-135 minutes). Total occlusion rate at follow-up (mean 19 months, range 1-33) was 98.1%. No significant recurrent neurological events were observed. Transcatheter closure of PFO with or without ASA is a safe and effective, minimally invasive procedure that ensures high closure rate and avoids life-long anticoagulation. Mid-term follow-up results appear favorable with respect to recurrent thromboembolic events.