Observation of Mitral Apparatus Change in Acute Ischemic Mitral Regurgitation by Live Three-Dimensional Echocardiography

Abstract

Objective. Mitral apparatus geometry changes during ischemic mitral regurgitation (MR) play an important role in finding mechanisms for ischemic MR. Live three-dimensional echocardiography (L3DE) is a new technique providing cardiac full-volume image in a very short time. We applied this technique to evaluate mitral apparatus geometry changes during acute ischemic MRs.Methods. After baseline two-dimensional echocardiography (2DE) and L3DE image acquiring, the left circumflex (LCX) coronary artery distal to the first obtuse marginal artery origin was ligated in order to produce an acute ischemic MR in 10 canines. When significant ischemic MR occurred, 2DE and L3DE imagings were repeated. PM tethering distance and mitral annular geometric dilation were measured by L3DE.Results. Acute ischemic MR was successfully produced by LCX ligation in 8 canines. MR grade increased from 0.5±0.2 at baseline to 2.4±0.2 during ischemic MR in scale, P2=0.77).Conclusions. Live three-dimensional echocardiography can show mitral annulus spatial configuration and can be used to address questions related to mitral apparatus. Mitral apparatus geometry changes are contributed to acute ischemic MR.