Atrial septal aneurysm: a new classification in two hundred five adults.

Atrial septal aneurysm is a localized "saccular" deformity, generally at the level of the fossa ovalis, which protrudes to the right or the left atrium or both. For 39 months we prospectively analyzed 205 consecutive patients in whom atrial septal aneurysm was diagnosed echocardiographically. The direction and movement of atrial septal aneurysms were carefully studied in multiple views, and, according to our findings, we now propose a new classification: type 1R if the bulging is in the right atrium only, type 2L if the bulging is in the left atrium only, type 3RL if the major excursion bulges to the right atrium and the lesser excursion bulges toward the left, type 4LR if the maximal excursion of the atrial septal aneurysm is toward the left atrium with a lesser excursion toward the right atrium, type 5 if the atrial septal aneurysm movement is bidirectional and equidistant to both atria during the cardiorespiratory cycle. We found an incidence of 1.9%, a mean age of 63 years (25 to 97 years), a female/male ratio of 2:1, valvular regurgitation 74%, hypertension 64%, left ventricular hypertrophy 38%, coronary heart disease 32%, patent foramen ovale 32%, pulmonary hypertension 31%, stroke 20%, dysrhythmias 16%, valvular prolapse 15%, and atrial septal defect 3%. No differences were found between mobile and motionless types of atrial septal aneurysm. However, differences were found between predominantly left bulging or right bulging atrial septal aneurysm (134 versus 57 patients), as well as other variables. All types of atrial septal aneurysm have particular clinical or echocardiographic characteristics. The new classification is a complete, simple, and practical form. Atrial septal aneurysm is associated with congenital and acquired heart diseases but also can present as an isolated abnormality.