The clinical significance of
new fill-in observed by
thallium-201 (201Tl) reinjection in myocardial segments with persistent defect in the subacute phase of
myocardial infarction was investigated. Seventy-five patients with subacute phase (mean 20th day) of first
myocardial infarction underwent stress-redistribution-reinjection 201Tl single photon emission computed tomography (SPECT) imaging. Percentage 201Tl uptake was calculated and classified as persistent defect without fill-in even after reinjection (PD group, n = 26, 35%), persistent defect with
new fill-in after reinjection [REINJ (+) group, n = 19, 25%] and reversible defect [RD (+) group, n = 24, 32%]. The clinical features and angiographic findings were assessed in the same phase in each group. Diameter
stenosis of the
infarction-related arteries by coronary angiography was 68 +/- 34% in the PD group, 31 +/- 23% in the REINJ (+) group and 83 +/- 27% in the RD (+) group [p < 0.01, REINJ (+) group vs PD group and RD (+) group]. Wall motion of the infarcted myocardial segments significantly improved and the mean left ventricular ejection fraction (EF) was higher in the REINJ (+) group than in the PD group (mean EF 51% vs 43%, p < 0.01). Post
infarction angina was more frequent in the RD (+) group than in the REINJ (+) group (38% vs 5%, p < 0.05). Although
new fill-in-after 201Tl reinjection has been considered to indicate severe
myocardial ischemia in chronic
coronary disease, these results indicate that this phenomenon in viable myocardium in patients with subacute phase of
myocardial infarction is not always related to residual
ischemia in the infarcted myocardial area.