[Atrial septal aneurysm: a report of three cases].

Three cases of isolated atrial septal aneurysm are reported. Case 1: A 66-year-old man visited our hospital for detailed examination and evaluation of premature ventricular contractions and left ventricular hypertrophy previously detected. Echocardiography revealed an atrial septal aneurysm protruding into the left atrium in the early systolic phase and into the right atrium during the mid-systolic to diastolic phase. Subxiphoid M-mode echocardiography showed triphasic movement of the wall of the atrial septal aneurysm toward the left atrium during the end-diastolic to systolic phase, which was enhanced during inspiration. No abnormalities were found by Doppler echocardiography. Cardiac catheterization revealed normal intracardiac pressures and oxygen saturations, but a right arteriogram revealed a defect in the right atrium. Case 2: A five-month-old male infant was referred to our hospital for detailed examination and evaluation of a heart murmur. Echocardiography revealed an atrial septal aneurysm in which a part of the interatrial septum protruded into the right atrium. Case 3: A one-day-old female infant was admitted to our hospital for detailed cardiac examination. Echocardiography revealed that the entire interatrial septum protruded into the right atrium. In Cases 2 and 3 the morphology of the aneurysms did not show cyclic or respiratory change. These two cases had no other abnormalities on echocardiography or Doppler echocardiography. The mechanism of the wall movement in Case 1 seemed to be attributed to differences in pressures between the right and left atria and in properties of the aneurysmal walls. Enhancement of the protrusion of the aneurysmal wall toward the left atrium during inspiration was considered due to inspiratory increase of right atrial pressure.