Left intra-atrial membrane without pulmonary vein obstruction: benign condition of progressive evolution? Apropos of 7 cases - Dauphin,C.; Lusson,J.R.; Motreff,P.; Lorillard,R.; Briand,F.; Valy,Y.; Lamaisaon,D.; Chabrun,A.; Cassagnes,J. (Arch Mal Coeur Vaiss, 1998)