Color flow mapping in perimembranous ventricular septal defect with left ventricular-to-right atrial shunts

The natural history of ventricular septal defect (VSD) varies with the exact location of the defect and also with the tissue changes surrounding it. Seven cases of perimembranous trabecular VSD were noted during color Doppler echocardiographic examination to have left ventricular-to-right atrial (LV-to-RA) shunts in association with aneurysmal transformation of VSD. Repeated cardiac catheterization documented the role of aneurysmal transformation in the increase of LV-to-RA shunts. A VSD located near the antero-septal commissure was diagnosed in all cases by echocardiography from the apical 5-chamber and parasternal inflow views. Echocardiographic signs of LV-to-RA shunts are high velocity backward turbulence in the RA without the presence of an elevated right ventricular systolic pressure and a two-directional turbulence through the "transformed" VSD. Corrective surgery confirmed the diagnosis in one case. Another case was complicated by an episode of viridans streptococcal endocarditis. The significance of LV-to-RA shunts in perimembranous trabecular VSD remains unknown.