IntroductionSerious hemodynamic deterioration by left ventricular outflow tract (LVOT) obstruction following catecholamine infusion in anteroseptal acute myocardial infarction (AMI) has been reported [1][2][3][4][5]. It has been reported that LVOT obstruction in hypertrophic obstructive cardiomyopathy (HOCM) is related to 1) excessive anterior mitral leaflets beyond coaptation due to anteriorly located papillary muscles and abnormally elongated leaflets [6][7][8][9][10][11][12], 2) excessive posterior mitral leaflets [13], 3) reduced chordal tension, and others. However, the mechanism of LVOT obstruction following catecholamine infusion in anteroseptal AMI without left ventricular hypertrophy (LVH) has not been established.In anteroseptal AMI following catecholamine infusion without LVH, reduced mitral annular size due to hyperkinetic basal posterior wall can potentially cause excessive mitral leaflets, leading to its systolic anterior motion (SAM) and LVOT obstruction (Fig. 1). Therefore, the purpose of this study is to investigate the relation between the decrease in mitral annular dimension and the LVOT obstruction following catecholamine infusion in a canine model of AMI.
Left Ventricular Outflow Tract Obstruction