Dobutamine Echocardiography and Quantitative Rest-Redistribution 201 Tl Tomography in Myocardial Hibernation

Abstract

Background The purposes of this study were to evaluate the comparative accuracy of dobutamine echocardiography and quantitative rest-redistribution 201 Tl tomography in the prediction of recovery of function after revascularization and to assess the relation of contractile reserve to thallium uptake. Methods and Results Thirty-four patients with stable coronary disease and regional dysfunction underwent dobutamine echocardiography (2.5 up to 40 μg·kg −1 ·min −1 ) and rest-redistribution 201 Tl tomography 1 day before revascularization. Resting echocardiography and scintigraphy were repeated at ≥6 weeks. Before revascularization, resting 201 Tl uptake was similar in segments demonstrating biphasic or sustained improvement and was higher than in those exhibiting no change or worsening function during dobutamine. After revascularization, 201 Tl uptake increased only in segments that showed a biphasic response (from 66±12% to 78±13%; P <.05). Biphasic response had a sensitivity of 74% and specificity of 89% for prediction of recovery. The use of biphasic or sustained improvement responses increased the sensitivity to 86% with a decrease in specificity to 68%. Qualitative thallium assessment provided a high sensitivity (98%) but poor specificity (27%). Quantification of thallium uptake, however, improved its accuracy: a maximal uptake (at rest or redistribution) of ≥60% yielded a 90% sensitivity and a 56% specificity. Conclusions In patients with myocardial hibernation, biphasic response during dobutamine is less sensitive but more specific for recovery of function, whereas indexes of 201 Tl scintigraphy are in general more sensitive and less specific, the least accurate being a qualitative assessment of thallium uptake. The sensitivity and specificity of both methods, however, can be altered depending on the quantitative criteria of thallium uptake or combination of responses of the myocardium to dobutamine.