Clinical value of phase and amplitude images and left ventricle time-activity curves in assessing patients with acute myocardial infarction.

The purpose of this study was to assess the clinical usefulness of phase and amplitude images and of the left ventricle time-activity curve (LVTAC) obtained by equilibrium gated radionuclide ventriculography (EGRV) in patients with acute myocardial infarction (AMI). Fifty-six patients were studied within 4 days of the onset of AMI by EGRV; of these 49 also underwent first-pass (FP) angiocardiography, for comparison with EGRV, and 21 underwent repeated EGRV 3 months after AMI. Phase and amplitude images were obtained by Fourier analysis. LVTAC analysis was performed by a third degree polynomial fitting to determine peak ejection rate (PER) and peak filling rate (PFR). A substantial equivalence of EGRV and FP methods was demonstrated, as regards left ventricle ejection fraction (LVEF), while a sharp superiority of EGRV with Fourier analysis was shown with regard to the sensitivity of RWM abnormality detection. With only one exception all the cases showed RWM abnormalities, while LVEF was normal in 21 of 27 patients with less than three affected segments. The most sensitive global function index was the LVPFR. In the acute phase regional dyskinesis was observed in 14 of 56 patients. About 40% of our cases showed an improvement of the kinetic abnormalities 3 months after AMI. The highest rate of improvement was observed in the group with ECG patterns of limited infarction and with normal LVEF.