Unusual mechanism of tricuspid regurgitation in ventricular septal defect

A 37-year-old woman was diagnosed to have a small ventricular septal defect (VSD) with high velocity tricuspid regurgitation (TR) that was attributed to atrio-VSD (Gerbode). Cardiac MR revealed a small subaortic VSD in the membranous portion of the interventricular septum. The atrioventricular portion was intact. Cardiac MR clearly showed flow jet through the VSD, impinging on the anterior tricuspid leaflet during systole, and bouncing back into the right atrium as TR. This ricochet mechanism of TR in VSD may be misinterpreted as Gerbode defect or as evidence of pulmonary hypertension. (Echocardiography 2011;28:E36-E38) A 37-year-old woman was found on echocardiogram with a perimembranous ventricular septal defect (VSD) associated with high velocity tricuspid regurgitation (TR) jet that was attributed to atrio-VSD and supported by a step-up of oxygen saturation in the right atrium (RA). Cardiac MR confi rmed the presence of a small perimembranous VSD and demonstrated that the TR jet was actually a jet of fl ow through the VSD, impinging on the anterior tricuspid leafl et and bouncing back into the RA as TR. This ricochet mechanism of TR in VSD could be misinterpreted as Gerbode defect, or as evidence of pulmonary hypertension.