Atrial arrhythmias and lipomatous hypertrophy of the cardiac interatrial septum

Abstract

Excessive accumulation of fat in the interatrial septum, termed lipomatous hypertrophy of the interatrial septum, was found at postmortem examination in ten elderly patients. All patients had atrial arrhythmias. Seven patients had unusual arrhythmias including multifocal atrial tachycardia, wandering atrial pacemaker, paroxysmal atrial tachycardia, and sinus arrest, all of which proved refractory to therapy. In five patients an unusual “dome and dip” P-wave configuration was noted in Leads II, III, and aV F of the electrocardiogram. It is suggested that these arrhythmias may be related to the excessive accumulation of fat in the interatrial septum and that the described P-wave morphology may be an indicator of interatrial block due to such accumulation.