[Prediction of the myocardial contractility improvement on early stage after the revascularization using low-dose dobutamine stress 99mTc-MIBI gated SPECT].

ABSTRACT

For prediction of recovery of LV contractility, 99mTc-MIBI gated SPECT at rest and that with dobutamine (DOB) loading were performed in 15 patients with myocardial infarction (MI). Regional % uptake (regionalx100/maximal count), % wall thickening [%WT; (ES-ED)x100/ED maximal count], and delta %WT (%WT at DOB stress-%WT at rest) were calculated for each of 8 segments (seg.), including 34 MI out of total 120 seg., which derived from short axis LV count profile. These 34 seg. were divided into two groups, recontractile (18 seg.) and non-recontractile (16 seg.), whether improvement of the wall motion following the intervention (3-5 months) was observed by echocardiography. In the result, there were 7 recontractile seg. in 8 seg. with mildly reduced perfusion (> or = normal mean % uptake-2 S.D.), and there were 11 recontractile seg. in 26 seg. with severe reduced perfusion (< normal mean % uptake-2 S.D.). Moreover, in segments with severely reduced perfusion, there was no significant % uptake difference between recontractile and non-recontractile seg. However, delta %WT of recontractile group (11.1 +/- 4.8%) was significantly higher than that of non-recontractile group (5.7 +/- 2.9%) (p < 0.01). In conclusion, although the improvement of contractility on early stage after the revascularization was sometimes underestimated with only perfusion (% uptake), myocardial DOB response of %WT which were obtained by gated SPECT with MIBI would avoid the underestimation.