Circulation: Cardiovascular Imaging Topic Review Circulation: Cardiovascular Imaging Editors’ Picks

Uncorrected chronic ischemic mitral regurgitation (CIMR) is associated with decreased left ventricular (LV) torsion and may contribute to a vicious cycle wherein “MR begets MR.” It has not been definitively established, however, whether the reduced LV torsion in CIMR is a direct result of the infarct, the MR, or a combination of the two. Currently, the most common technique to restore valve competence in patients with CIMR is the placement of an undersized annuloplasty ring. There exists, however, an ongoing debate about whether or not mitral valve annuloplasty at the time of coronary artery bypass grafting (CABG) improves outcomes over and above CABG alone. Hypothetically, if the reduction in LV torsion can be attributed to MR alone, then mitral valve repair concomitant with CABG may be important for minimizing the deterioration in LV torsion. Chronic “pure” MR was created in 13 sheep by surgically punching a 3.5–4.8-mm hole (HOLE) in the mitral valve posterior leaflet. Nine control sheep were operated on concurrently. At 1 week and 12 weeks after surgery, the 4D motion of implanted radiopaque markers was used to calculate global LV torsion. Global LV systolic torsion decreased in HOLE from week 1 to week 12 (4.1 2.8° versus 1.7 1.7°, P 0.01) but did not change in control (5.5 1.8° versus 4.2 2.7°, P NS). These data suggest that in patients with CIMR, the MR itself may promote deterioration of LV torsion. MV repair in patients with CIMR concomitant with CABG may therefore help to slow down, stop, or even restore physiological LV torsion.