Abstract

Left ventricular (LV) diastolic filling is impaired in hearts with healed myocardial infarction. Possible hemodynamic parameters related to impaired LV filling include left atrial pressure, time constant of isovolumic relaxation, chamber stiffness and wall motion asynchrony. Previous studies demonstrated univariate correlations between each of these 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 measurement were analyzed in 15 patients with a myocardial infarction and in 10 control subjects. Every frame of the left ventriculogram was divided into 8 segments and the volume of each segment was obtained frame-by-frame by planimetry and area-length method. Asynchrony was quantitated as the sum of areas of discrepancy between each segmental and global volume-time curve. Patients with myocardial infarction had greater asynchrony (20 +/- 2 vs 10 +/- 1%, p < 0.01), greater atrial filling fraction (46 +/- 4 vs 35 +/- 5%, p < 0.05) and slower peak early filling rate (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 variables (asynchrony, LV pressure at mitral valve opening, time constant 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 infarction, whereas LV pressure at mitral valve opening was the only significant determinant in control subjects.