Closing an iatrogenic atrial septal defect (iASD) following transcatheter mitral valve edge-to-edge repair (TMVR) leads to a volume shift from the right ventricle (RV) to the left ventricle (LV), with a reduction in pulmonary cardiac index but increase in systemic cardiac index and with favorable biventricular interaction at unchanged LV filling pressure, all resulting in a decline in heart failure symptoms at 1-month follow-up, according to a study released Monday.