AIM OF THE STUDY: After the abdomen and the thorax, the cardiac approach seems to be the logical next step in development of minimally invasive surgery. We report our initial experience in closure of patient foramen ovale (PFO) through a mini thoracotomy. METHOD: A cardio-pulmonary bypass is initiated through canulaes introduced into the external iliac artery and vein. A right anterior mini-thoractomy is performed in the fourth intercostal space and a video-endoscopic camera is introduced through a trocar placed more laterally. The pericardium is opened anteriorly to the phrenic nerve. A venous canula is introduced into the superior vena cava and connected to the extracorporeal circuit. A ventricular fibrillation is provoked and both vena cavaes are clamped before the right atrium is opened. The PFO is closed with a double running suture. DISCUSSION: From November 1996 to march 1997, 4 patients were operated that way. The mean operation time was 212 +/- 17 minutes, the mean CPB time was 73 +/- 32 minutes, and the mean fibrillation time was 32 +/- 15 minutes. Echocardiography was performed at the end of the operations and at day 7. No residual shunt was detected and the cardiac function was not changed compared to the preoperative examination. CONCLUSION: Closure of a PFO can be performed through a mini-thoracotomy, with good results. With growing experience, the "minimally invasive" approach shall rapidly become a standard technique for this indication.