The Study Of Left Ventricular Pressure Changing On Left Atrium Function Under Ischemia Using Strain Rate Imaging

Objective:To evaluate whether the left atrium(LA)function will be affected by the pressure changing of left ventricle(LV)during the LV ischemia using strain rate imaging(SRI).Method:11 healthy dogs were occluded with left anterior descending coronary artery(LAD)for acute ischemia of regional anterior left ventricular wall.Peak strain rate(PSR)value of left atrium(LA)walls during reservoir(including early reservoir LR and late reservoir LR),conduit(CD)and contractile(CT)were measured both at pre and post ischemia respectively.Simpson method was used to measure the left ventricular eject fraction(LVEF)and non-invasive LA volumic and functional indices.Parameters of spectrum from mitral valve and pulmonary vein,and catheter-measured pressure of LV were also gotten at pre and post ischemia.Results:Pre-atrial contraction LA volume(VpreA),minimal LA volume(Vmin),maximal LA volume(Vmax)and LA expansion index (LAEI)increased after ischemia(P＜0.001().CT-PSR,PSR-ER,PSR-LR and CD-PSR of all walls increased after ischemia(P＜0.001).Left ventricular end diastolic pressure(LVEDP)increased after ischemia(P＜0.0001)and its changing rate LVEDP%positively correlated with changing rate of CT-PSR(CT-PSR%)of anterior and lateral wall, changing rate of LR-PSR(LR-PSR%)and CD-PSR(CD-PSR%)of inferior wall respectively(r=0.72,0.72,0.83,0.73.P=0.05,0.05,0.002,0.01). LVEF decreased(P＜0.05)and its changing rate EF%negatively correlated with changing rate of ER-PSR(ER-PSR%)of anterior and lateral wall, CD-PSR%of inferior and lateral wall respectively(r=-0.80,-0.86, -0.81,-0.80.P=0.003,0.001,0.003,0.003).Conclusion:LA function will be partially affected by the pathyphysilogical especially LVEDP and EF changing raised by regional LV ischemia.Presented as the compensated increased wall deformation during regional acute LV ischemia.