title: Detection of small subendocardial infarction using speckle tracking echocardiography in a rat model.
abstract: BACKGROUND
  It is challenging to detect small nontransmural infarcts visually or automatically. As it is important to detect myocardial infarction (MI) at early stages, we tested the hypothesis that small nontransmural MI can be detected using speckle tracking echocardiography (STE) at the acute stage.
  
  
  METHODS
  Minimal nontransmural infarcts were induced in 18 rats by causing recurrent ischemia-reperfusion of the left anterior descending (LAD) coronary artery, followed by a 30-min ligation and by reperfusion. A week later, the scar size was measured by histological analysis. Each rat underwent three echocardiography measurements: at baseline, 1 day post-MI, and 1 week post-MI. To measure the peak circumferential strain (CS), peak systolic CS, radial strain (RS), and time-to-peak (TTP) of the CS, short-axis view of the apex was analyzed by a STE program. The TTP was normalized by the duration of the heart cycle to create percent change of heart cycle.
  
  
  RESULTS
  Histological analysis after 1 week showed scar size of 4±6% at the anterior wall. At 24 h post-MI, the peak CS, peak systolic CS, and RS were reduced compared to baseline at the anterior wall due to the MI, and at the adjacent segments-the anterior septum and lateral wall, due to stunning (P<.05). However, only the anterior wall, the genuine damaged segment, showed prolonged TTP vs baseline (baseline 36%, 24 h 48%, P<.05).
  
  
  CONCLUSIONS
  The TTP of the CS can distinguish between regions adjacent to MI (stunned or tethered) and MI, even in small nontransmural infarcts.
authors.affiliation: Department of Computational Science and Bioinformatics, Migal, Tel-Hai, Israel. noa.bach@gmail.com.
authors.forename: Noa
authors.initials: N
authors.lastname: Bachner-Hinenzon
authors.affiliation: Faculty of Biomedical Engineering, Technion-Israel Institute of Technology, Haifa, Israel.
authors.forename: Liron
authors.initials: L
authors.lastname: Shlomo
authors.affiliation: Faculty of Biomedical Engineering, Technion-Israel Institute of Technology, Haifa, Israel.
authors.forename: Hanan
authors.initials: H
authors.lastname: Khamis
authors.affiliation: Eliachar Research Laboratory, Western Galilee Hospital, Nahariya, Israel.
authors.forename: Offir
authors.initials: O
authors.lastname: Ertracht
authors.affiliation: Department of Cardiology, Assaf Harofeh Medical Center, Zerifin, Israel.|Sackler School of Medicine, Tel Aviv University, Tel Aviv, Israel.
authors.forename: Zvi
authors.initials: Z
authors.lastname: Vered
authors.affiliation: Department of Physiology, Rappaport Family Institute for Research in the Medical Sciences, Technion-Israel Institute of Technology, Haifa, Israel.|Ruth and Bruce Rappaport Faculty of Medicine, Rappaport Family Institute for Research in the Medical Sciences, Technion-Israel Institute of Technology, Haifa, Israel.
authors.forename: Assaf
authors.initials: A
authors.lastname: Malka
authors.affiliation: Department of Physiology, Rappaport Family Institute for Research in the Medical Sciences, Technion-Israel Institute of Technology, Haifa, Israel.|Ruth and Bruce Rappaport Faculty of Medicine, Rappaport Family Institute for Research in the Medical Sciences, Technion-Israel Institute of Technology, Haifa, Israel.
authors.forename: Ofer
authors.initials: O
authors.lastname: Binah
authors.affiliation: Faculty of Biomedical Engineering, Technion-Israel Institute of Technology, Haifa, Israel.
authors.forename: Dan
authors.initials: D
authors.lastname: Adam
mesh_terms: D000818:Animals; D004452:Echocardiography / Q000379:methods*; D054459:Elasticity Imaging Techniques / Q000379:methods*; D004699:Endocardium / Q000000981:diagnostic imaging*; D009203:Myocardial Infarction / Q000150:complications / Q000000981:diagnostic imaging*; D017682:Myocardial Stunning / Q000000981:diagnostic imaging* / Q000209:etiology; D051381:Rats; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity
keywords: myocardial infarction; myocardial strain; stunning; viability