Since July, 1978, we have inserted a roller pump type of left heart assist device between the left atrium and ascending aorta in 35 patients. There were no significant complications related to use of the device. Seventeen patients recovered sufficiently to have the device removed. There were four early deaths, 60 to 120 days following removal of the device. Three of these patients died of septic complications and one patient died as a result of a cardiac arrest. Of the 13 long-term survivors, seven are working and six are retired. Five patients have mild to moderate cardiac symptoms, whereas eight others are completely asymptomatic. In three patients the ejection fraction was significantly lower than preoperatively; however, in all other patients the ejection fraction either stayed the same or improved postoperatively. We conclude that this type of left heart assist device can provide adequate cardiac support in patients with profound left ventricular dysfunction following cardiac operations. Furthermore, surviving patients generally have satisfactory long-term cardiac function and are leading productive lives.