Background: Aim of the present study was to compare the ability of low-dose (5-10 gamma/Kg/min) dobutamine echocardiography (DE) and of positron emission tomography (PET), performed after a thrombolized acute myocardial infarction (AMI), to predict the spontaneous functional recovery (SFR) of viable but akinetic myocardial segments.
Patients and methods: Twenty-one pts were studied by DE, 10 +/- 2 days (DE1) and 31 +/- 2 days (DE2), after a thrombolized AMI, and by PET (18F-FDS, glucose load) within 7 days after DE2; a basal echo was also performed 3 months after AMI. The left ventricle was divided in 16 segments, both in echo and PET examination. DE viability was defined as improvement in wall motion of akinetic seg; PET viability was defined as an FDG uptake > or = 40% of the maximum.
Results: In the 89 akinetic segments, DE1, DE2 and PET, respectively, identified, 16, 27 and 60 viable segments; the concordance with PET, in viable and not viable segments, resulted of 50% for DE1 and of 62% for DE2. After 3 months 29/89 segments had a SFR. In comparison with SFR the sensitivity of DE1 and DE2 was lower (51% and 68%) than PET (89%); the specificity was higher for DE1 and DE2 (98% and 96%) respect to PET (43%).
Conclusions: In comparison with DE performed 10 days after a thrombolized AMI, DE performed 30 days after AMI revealed a greater extension of viable myocardium and a greater diagnostic accuracy in predicting SFR of akinetic segments. The concordance between DE and PET is high, if all myocardial segments are considered, and lower, if only akinetic segments are considered; in fact, PET identifies, as viable, a greater number of segments. In comparison with SRF, DE revealed the greatest specificity and PET the greatest sensitivity.