Lipomatous hypertrophy of the interatrial septum presenting as sick sinus syndrome.

Lipomatous hypertrophy of the interatrial septum is a benign cardiac mass characterized by fat accumulation in the interatrial septum. Cardiac arrhythmias including atrial fibrillation, atrial premature contractions and atrioventricular block may occur as a consequence of involvement of the atrial wall and atrioventricular conduction pathways. We describe a patient with lipomatous hypertrophy of the interatrial septum associated with sick sinus syndrome.