WALL-MOTION ASYNCHRONY IS A MAJOR DETERMINANT OF IMPAIRED LEFT-VENTRICULAR FILLING IN PATIENTS WITH HEALED MYOCARDIAL-INFARCTION

Left ventricular (LV) diastolic filling is impaired in hearts with hea led myocardial infarction. Possible hemodynamic parameters related to impaired LV filling include left atrial pressure, time constant of iso volumic relaxation, chamber stiffness and wall motion asynchrony. Prev ious studies demonstrated univariate correlations between each of thes e parameters and LV filling, The current study was designed to compare relative importance of these parameters in patients with a myocardial infarction. Left ventriculograms with simultaneous LV pressure measur ement were analyzed in 15 patients with a myocardial infarction and in 10 control subjects. Every frame of the left ventriculogram was divid ed into 8 segments and the volume of each segment was obtained frame-b y-frame by planimetry and area-length method. Asynchrony was quantitat ed as the sum of areas of discrepancy between each segmental and globa l volume-time curve. Patients with myocardial infarction had greater a synchrony (20 +/- 2 vs 10 +/- 1%, p <0.01), greater atrial filling fra ction (46 +/- 4 vs 35 +/- 5%, p <0.05) and slower peak early filling r ate (2.5 +/- 0.1 vs 4.1 +/- 0.4 end-diastolic volume/s, p <0.01) than the control subjects. Multiple regression analyses with hemodynamic va riables (asynchrony, LV pressure at mitral valve opening, time constan t of LV isovolumic pressure decrease and LV chamber stiffness constant ) showed that asynchrony and LV pressure at mitral valve opening were significant determinants of LV filling in patients with myocardial inf arction, whereas LV pressure at mitral valve opening was the only sign ificant determinant in control subjects.