A 70-year-old woman was admitted to our hospital for treatment of right heart failure 16 years after undergoing Bentall's operation with a Cabrol shunt procedure. Various investigations showed detachment of the coronary artery and graft. We surmised that the heart failure was caused by a massive left to right shunt between a pseudoaneurysm of the wrapping aortic wall and the right atrium. Intraoperatively, we found a small fistula between the wrapping aortic wall and the right atrium, with complete closure of Cabrol shunt. We performed regrafting of the ascending aorta and reconstruction of the coronary ostium under cardiopulmonary bypass. The patient had an uneventful postoperative course. Detachment of the coronary ostium is a common long-term complication of Bentall's operation, but a Cabrol shunt between the wrapping aortic wall and the right atrium rarely causes congestive heart failure. A fistula between a pseudoaneurysm and the right atrium is even more unusual.