Assessment of reversible dyssynergic segments after acute myocardial infarction : Dobutamine echocardiography versus thallium-201 single photon emission computed tomography

Only a moderate degree of concordance has been reported between stress-redistribution-reinjection thallium-201 single photon emission computed tomography (SPECT) and dobutamine echocardiography for the identification of myocardial viability after acute myocardial infarction. SPECT with rest-reinjection performed 4 hours after exercise testing and digitized two-dimensional (2-D) ultrasound reconstruction of the left ventricle at baseline and after low-dose dobutamine (5 to 10 μg/kg/min) infusion were compared in 50 patients ≥8 days (12 ± 7 days) after acute myocardial infarction. Five patients were excluded because of technically inadequate echocardiograms. Both SPECT and dobutamine echocardiography were assessed in a 16-segment model and interpreted in the remaining 45 patients. Digitized 2-D reconstruction of the left ventricle in each wall motion was scored from 1 (normal) to 4 (dyskinesia). Myocardial viability was identified on ultrasound wall-motion improvement of one or more grades from baseline to echocardiography performed ≥30 days (60 ± 41 days) after systematic revascularization procedure of the infarct-related artery. Reversible defect under thallium-201 SPECT and wall-motion improvement under dobutamine echocardiography were concordant in 163 (69%) of the 235 baseline dyssynergic segments and in 30 (67%) patients. Myocardial viability was identified after angioplasty (n = 37) or surgery (n = 8) in 29 patients and 109 segments. Positive and negative predictive values per patient in the diagnosis of myocardial viability were 86% and 57%, respectively, for stress thallium-201 SPECT with reinjection, and 100% and 62% for dobutamine echocardiography. Positive and negative predictive values per segment were 80% and 69% for the isotopic method and 91% and 70% for dobutamine echocardiography. We conclude that dobutamine echocardiography and stress thallium-201 SPECT with reinjection have similar accuracies to identify myocardial viability after acute myocardial infarction, with excellent positive but relatively low negative predictive values.