Assessment of hybernating myocardium by tissue Doppler and strain Doppler dobutamine echocardiography

Objective. The aim of this present study was to assess the quantitative segmental analysis by strain rate imaging (SRI) technique during dobutamine test for detecting myocardial viability in patients with chronic ischemic regional left ventricular (LV) dysfunction, to compare results with those of tissue Doppler imaging (TDI) as well as rest-4h-24h redistribution Thallium SPECT (Tl SPECT), and to establish the accuracy of dobutamine SRI, dobutamine TDI and Tl SPECT before and after revascularization. Methods. Thirty-three patients with chronic ischemic regional LV dysfunction (EF 297%) underwent dobutamine TDI/SRI and Tl SPECT on different days randomly within 15 days before myocardial revascularization. Velocity and strain traces from different wall segments were processed simultaneously in the same cineloop. Dobutamine was administered by infusion pump, at 3 min intervals up to a maximum of 20 mcg/Kg/min. Each patient was injected i.v. with 3.0 mCi of Tl in the rest state. Four hours and 24 hours after injection, delayed Tl SPECT acquisitions were performed using the same parameters. A 17-segment- 4-grade score model was used for analysis of both Dobutamine SR and Tl SPECT. Offline analysis of the myocardial velocity data sets was performed using dedicated software. Recovery of regional LV function was defined as wall motion score improvement  1 grade in  2 contiguous segments at resting follow-up echocardiogram in patients with angiographically controlled open target vessel. Results. Positive and negative predictive values were 82% and 79% for dobutamine TDI, 89% and 83% for dobutamine SRI, and 76% and 94% for Tl SPECT. The area under the ROC curve (AUC) which reflects the overall performance for the prediction of recovery was 0.79 for systolic-SRI, 0.82 for Tl SPECT, 0.83 for post-systolic strain and 0.88 for isovolumic-SRI. Conclusion. Systo-diastolic values obtained using dobutamine SRI echocardiography and values derived from nuclear perfusion techniques may be complementary in assessing hibernating myocardium.