1) Situs ambiguous (SA) is defined as an abnormality which can be considered to be present when the thoracic and abdominal organs are not clearly lateralized.2) SA is typically associated with complex cardiovascular malformations. Also, splenic abnormalities and intestinal malrotation are common. Thus SA is usually categorized either as splenic morphology – polysplenia (bilateral left-sidedness, usually with multiple spleens, left isomerism, namely, polysplenia syndrome) or as asplenia (bilateral right-sidedness, with absence of spleen, right isomerism, namely, asplenia syndrome).2) SA with polysplenia (SAP) is considerably rarely found in adults

because of its high mortality rate with severe anormalies.3) However, patients with minor cardiac Inhibitors,research,lifescience,medical Inhibitors,research,lifescience,medical deformities can survive to adulthood.1) We report 2 cases of incidentally detected SAP. Case Case 1 A 42-year-old male was admitted for radiofrequency ablation of atrial fibrillation (AF). He was diagnosed as AF 4 years ago and took anti-arrhythmic agent, beta blocker

and anticoagulant. He had left side weakness due to cerebral infarction of right middle cerebral artery territory 3 years ago. He had a history of hypertension. His family had no history of diseases or congenital abnormality. He had no other symptoms but PS-341 intermittent palpitation. His heart sound was irregular, but nothing particular was revealed on Inhibitors,research,lifescience,medical other physical and laboratory examinations. Double the shadow of thoracic aorta Inhibitors,research,lifescience,medical and widening state of superior mediastinum were shown in chest X-ray, but there were no other remarkable matters (Fig. 1). Initial electrocardiogram showed AF with moderate ventricular response (average 60-80 beats/min).

On transthoracic and transesophageal echocardiography, no structural cardiac abnormalities were revealed. It seemed that hepatic vein was connected to right atrium through inferior vena cava (IVC) as usual. There was no pulmonary hypertension. We checked coronary multidirectional computed tomography Inhibitors,research,lifescience,medical (MDCT) to identify the anatomical variations of the patient’s coronary vessels and heart before the ablation procedure. There was a tubular structure which was paralleling with descending thoracic aorta. It was supposed to be an IVC interruption with hemiazygos continuation (Fig. 2A). Hepatic veins were drained to right atrium. Abdomen computed tomography (CT) was performed to evaluate other combined abnormality. Multiple and round soft tissue densities were detected around the spleen, which CYTH4 were enhanced at the same degree of the spleen. Left-sided colon and right-sided small bowels indicated intestinal malrotation. IVC was located at the left side of aorta, and the hepatic segment of IVC was absent (Fig. 2B-D). By means of venography of IVC through right femoral vein, the interruption of the thoracic IVC with hemiazygos continuation along with aortic arch was confirmed (Fig. 3). All those findings were compatible with SAP. Fig.