EARLY AND LATE CHANGES IN LEFT-VENTRICULAR FILLING AFTER ACUTE MYOCARDIAL-INFARCTION AND THE EFFECT OF INFARCT SIZE

To characterize the early (1 week) and late (6 weeks) changes in left ventricular (LV) filling pattern associated with acute myocardial infarction (AMI) 45 patients (mean age 65 +/- 2 years) were studied by Doppler echocardiography. Based on clinical criteria, patients were divided into those with large (group L; n = 12) and those with small (group S; n = 33) infarcts and then compared with 16 age-matched control subjects. The following parameters were calculated from the mitral velocity waveform: (1) peak early and peak atrial velocities and their integrals; (2) peak early to atrial velocity ratio and velocity integral ratio; and (3) the pressure half-time of the early wave. One week after AMI, group L showed a decreased atrial and increased early velocity, velocity ratio and integral ratio, whereas the pressure half-time of the early wave was shorter than that in group S and in control subjects. At 6 weeks group L showed a reduction in early velocity, early to atrial velocity ratio and integral ratio, whereas pressure half-time increased. When groups S and L were combined there was a good inverse correlation between pressure half-time and infarct size as measured by peak enzyme release (r = -0.64, p <0.001). These data suggest that, depending on infarct size, patients exhibit a "restrictive" filling pattern early after the acute event. This is manifested by the greater proportion of filling occurring in early diastole, reflecting an overall increase in chamber stiffness. At 6 weeks, this pattern is less pronounced presumably due to the remodeling process.