Detection of residual tissue viability within the infarct zone in patientswith acute myocardial infarction: Ultrasonic integrated backscatter analysis versus dobutamine stress echocardiography

Objectives: The goals of this study were to analyze temporal changes in car diac cyclic variation of integrated backscatter (CVIB) in acute myocardial infarction (AMI) and to investigate the predictive value of CVIB normalizat ion compared with that of dobutamine stress echocardiography CDSE) in the a ssessment of functional recovery after revascularization. Background: The normal CVIB is blunted by ischemia and recovers early after reperfusion, faster than wall motion improvement. Analysis of CVIB has bee n widely investigated for its potential to detect viable myocardium in the early stage of infarction. No studies have compared CVIB analysis with othe r techniques for viability assessment in patients with acute ischemic. Methods and Results: Integrated backscatter images were obtained in 12 pati ents with AMI on days 1, 3, and 7 after admission and 1 month after revascu larization. On day 7, DSE was performed in all patients. On admission, 22 o f 144 segments were dyssynergic. On day 1, CVIB was abnormal in all 22 infa rcted segments, on day 3, in 16, and on day 7, in only 10 infarcted segment s. Eight of 10 segments nonviable by CVIB (CVIB-nonviable) were also nonres pondent by DSE; whereas 12 of 14 segments viable by DSE (DSE-viable) were a lso CVIB-viable. At follow-up, 10 CVIB-viable segments and 1 CVIB-nonviable segment showed functional recovery; whereas 10 of 14 DSE viable segments s howed functional recovery. Thus the positive predictive value of CVIB and D SE was 83% and 72%, respectively, with a diagnostic agreement between techn iques in 77% of segments. Conclusions: Our data suggest that the normalization in CVIB in the first w eek after AMI accurately predicts residual tissue viability within the infa rct zone. We also observed that the initial pattern of cyclic variation may be predictive of functional recovery. Finally, we found a good correlation between the recovery of a normal CVIB in segments that were still dysfunct ional and a more validated method to assess tissue viability, such as the d obutamine test.