The cardiac support device (CSD, Acorn Cardiovasc. Inc.), a knitted polyester tissue, is surgically placed over the ventricles to prevent further dilatation of the heart. The aim of this study was to evaluate the feasibility and safety of CSD implantation in patients with advanced heart failure from cardiomyopathy of either idiopathic or ischemic origin. From April 1999, 23 patients received the CSD. In 8 patients the CSD implantation was the only surgical measure; in 12 patients a concomitant mitral valve repair was performed. In three more patients, the CSD implantation was combined with other surgical procedures. The CSD was placed while on bypass with the heart beating, attached to the AV groove and tailored anteriorly to snugly fit the ventricles. There were no intraoperative deaths or complications. Two patients died early postoperatively (4 d, 21 d); 1 late death occurred (44 d postop). The deaths were not considered to be device related. There were no CSD-related adverse events. Six months postoperatively all patients improved by at least one NYHA class. Echocardiography at 6 months revealed an increase in LVEF; the LVEDD decreased accordingly. Mitral valve regurgitation improved in all patients. These findings indicate that the CSD is safe, and improves heart failure symptoms and left ventricular function. Additional studies have to confirm these results.