[An elder case of common atrium: surgical repair at a 56-year-old man]

A 56-year-old man was admitted to our hospital with dyspnea. The ultrasonographic and hemodynamic features proved complete absence of atrial septum. The data of catheterization showed right to left shunt (59%) and QP/QS value of 1.7 and also, oxygen saturation of pulmonary arterial blood (87%) was almost as same as that of systemic arterial blood (90%). The radical operation was performed of making a new atrial septum with artificial patch. He did not have the cleft of atrioventricular valves and anomalies of systemic venous drainages. We reported a case of common atrium, which was diagnosed for the first time at the age of 56.