ACUTE ORAL TRIMETAZIDINE ADMINISTRATION INCREASES RESTING TECHNETIUM 99M SESTAMIBI UPTAKE IN HIBERNATING MYOCARDIUM

Background. Trimetazidine is an antiischemic drug protecting the myoca rdium from ischemic damage through the preservation of mitochondrial o xidative metabolism, without any hemodynamic effect. Tc-99m-sestamibi is accumulated by myocytes according to mitochondrial function. As mit ochondrial metabolism is thought to be present in hibernating myocardi um, the aim of the study was to investigate trimetazidine effects on i nfarcted and eventually hibernating myocardial areas by means of Tc-99 m-sestamibi perfusional scintigraphy,; comparing them to postoperative recovery of mall motion. Methods and Results. Twelve patients with pr evious myocardial infarction underwent 2 perfusion imaging tomographic studies at rest with Tc-99m-sestamibi, receiving placebo or trimetazi dine (60 mg orally), and subsequently underwent revascularization proc edures. An echocardiographic study was carried out before and >3 month s after revascularization. At polar map analysis of placebo scan, infa rcted vascular territories (wall motion score index: 2.65 +/- 0.31) sh owed 73.7% +/- 10.4% of the territory with activity <2.5 SD from the m ean of normals, for a severity (expressed as the sum of the standard d eviations below average normal values in all abnormal pixels) of 833.8 +/- 345.7. Polar map analysis of the trimetazidine scan showed tracer uptake increased significantly in 11 of them, by 8.2% +/- 3.0% (p < 0 .001) and by 180.3 +/- 111.0 SD (p < 0.001), respectively. Postoperati ve wall motion score index improved significantly in 9 of these territ ories (-0.9 +/- 0.4, p < 0.001), Conclusions. Trimetazidine-associated increase in Tc-99m-sestamibi uptake in infarcted but viable myocardia l areas is probably related to an improvement in mitochondrial oxidati ve metabolism that is essential to Tc-99m-sestamibi retention, Additio nally, coupling trimetazidine administration to Tc-99m-sestamibi perfu sional scintigraphy may represent a means of detecting viable myocardi um.