Left Ventricular Relaxation in Old Myocardial Infarction : Abnormal Regional Wall Motion during Isovolumic Relaxation and Its Effects on the Left Ventricular Relaxation

The effects of the regionl left ventricular (LV) wall motion on the LV relaxation were studied in, 9 patients (pts) with old antero-septal myocardial infarction (OMI) who had an isolated disease of the left anterior descending coronary artery and in 8 normal subjects (NOR) who were diagnosed as atypical chest pain. LV silhoettes in the right anterior oblique view of the LV biplane cineangiogram (60 frame/sec) were outlined from the time of peak (-) dp/dt to the time of mitral valve opening. LV area was divided into 8 sectons by along (longitudinal) axis and by 3 short (transverse) axises which was perpendicular to the long axis and divided the long axis into the 4 equal distances. The areas of the 2 middle sections in the anterior (Aa) and the inferior (Ab) sides in these 8 sectons were measured, respectively. Basal and apical sections were excluded. During IRT in NOR group. Aa began to increase from 33.4 msec after peak (-) dp/dt, but Ab did not. In OMI group, on the other hand. Ab increased from 50 msec after peak (-) dp/dt, while Aa decreased, probably because of the passive shortening of the anterior segments by the expansion of the inferior segments. These wall motions during IRT suggest the shape change of LV. In OMI group, Ab/Aa began to decrease from 16.7 msec after peak (-) dp/dt, while in OMI group increased. The time course of the Ab/Aa could be reasonably fitted by a straight line (r≧0.9) in all cases. The slope of this line [28.2±16.0 (×10^<-3>) msec