Abstract
Lipomas consist of encapsulated, mature fat in the atrial wall or myocardium, whereas lipomatous hypertrophy of the atrial septum is not encapsulated. Lipoma and lipomatous hypertrophy can be found in the visceral and parietal pericardium, the right atrium, the atrial septum, or the ventricles. They may obstruct coronary ostia or cardiac valves and can be associated with arrhythmias.