Akira Goto

Assessment of area at risk and efficacy of treatment in patients with acute coronary syndrome using99mTc tetrofosmin imaging in humans

The determination of the myocardium at risk before intervention and the change in that region after intervention constitute a promising measurement tool for the assessment of acute therapy. A new99mTc labeled myocardial blood flow tracer,99mTc tetrofosmin, is expected to enable the evaluation of myocardium at risk because of the absence of redistribution. This preliminary study was performed in 9 patients with acute coronary syndrome (4 unstable angina and 5 acute myocardial infarction) to investigate whether recovery of perfusion by tetrofosmin imaging parallels mechanical improvement. Tetrofosmin imaging was performed acutely and 3–30 days later. Visual analysis of defect severity was assessed in both studies. Segments with improvement in perfusion were accompanied by significant wall motion recovery compared with normal and unimproved segments (Δ WMI: normal segments 0.40±0.67, improved segments 1.79±0.68, unimproved segments −0.15±0.16, p< 0.01 for improved segments compared with other groups), suggesting the efficacy of this tracer for the assessment of the acute therapy. These data suggest that99mTc tetrofosmin imaging is a useful method for the assessment of the myocardial area at risk and the efficacy of acute therapy in acute myocardial infarction and unstable angina.

Effects of molsidomine on right ventricular function

Abstract Right ventricular (RV) function was evaluated using the pressure-volume relationship derived from electrocardiographic-gated equilibrium radionuclide ventriculography and RV pressure data measured with a Swan-Ganz catheter. Computerized methods were developed to collect data simultaneously from the gamma camera, electrocardiograph, and RV pressure transducer. Such data are rarely obtained by traditional contrast ventriculography. From the pressure curve and volume curve, a pressure-volume loop was generated from which RV work was calculated. This newly developed technique was assessed in five control subjects and 10 patients with advanced congestive heart failure. Despite maintenance of net work, the pressure-volume loop clearly shifted toward the lower left part of the pressure-volume plane in seven patients who had an end-diastolic volume of more than 90 ml after oral administration of the vasodilator molsidomine.