Cardiac lipoma: a rare cause of right-to-left interatrial shunt with normal pulmonary artery pressure.

Cardiac lipomas are rare tumors. They usually remain asymptomatic for a long time and cause angina, arrhythmia, dysfunction of the ventricles or valves, and peripheral embolization during the later stages of development. There is little or no information about right-to-left interatrial shunt with normal pulmonary artery pressure, produced as a consequence of the infiltration of the atrial septum, the right atrial wall, and the myocardium because of the presence of fat in patients with platypnea-orthodeoxia syndrome. We present a patient with this syndrome who was identified through transesophageal echocardiography. The study showed a massive right-to-left shunt without pulmonary hypertension, produced by an important cardiac infiltration of adipose tissue that created a narrow passage in the right atrium, and a redirection of the flow to a patent foramen ovale, explaining the pathophysiology of the syndrome.