Abstract 5736: Diagnosis of Chronic Myocardial Ischemia by Speckle Tacking Echocardiography -A Comparative Animal Study-
A number of systolic and diastolic indexes for ischemic damage can be measured by 2D speckle tracking echocardiography (STE) including radial strain and strain rate as well as circumferential strain and strain rate on LV short-axis view. In addition, they could be derived from the subendocardium, subepicardium, mid-layer or total layer of the LV wall with new tracking software. The aim of our study is to compare the diagnostic abilities of these indexes in animal experiments. An Ameroid constrictor was placed around the left circumflex coronary artery in 19 pigs. Before and 4 weeks after the surgery, LV short-axis images were obtained at rest by transthoracic 2D echocardiography. Three pigs that had died after the surgery and 2 that had focal infarction in pathological studies were excluded from the study. Thus, in 14 pigs with 99% stenosis on coronary angiograms, we measured peak strain, peak S′, peak E′, time from QRS to peak strain, time from QRS to E′, and incidence of post-systolic shortening (PSS) in the endocardium, midcardium, and epicardium of the LV posterior wall using a new prototype speckle tracking software. None of the time indexes and PSS showed statistically significant results. ROC curve analysis (Table⇓) revealed that endocardial circumferential strain is the most diagnostic index of ischemia, which showed 79% sensitivity and 93% specificity. Endocardial circumferential strain measured by STE on LV short-axis view was the most useful index for detecting chronic severe myocardial ischemia.