title: Strain Analysis in the Detection of Myocardial Infarction at the Acute and Chronic Stages.
abstract: BACKGROUND
  Myocardial ischemia causes contractile dysfunction in ischemic, stunned, and tethered regions with larger infarcted zones having a negative prognostic impact on patients' outcomes. To distinguish the infarcted myocardium from the other regions, we investigated the diagnostic potential of circumferential strain (CS) and radial strain (RS) during the acute and chronic stages of myocardial infarction.
  
  
  METHODS
  Ten pigs underwent 90-minute occlusion of the left anterior descending artery, followed by reperfusion. Echocardiography was performed at baseline, after 90-minute occlusion, and at 2 hours, 30, and 60 days postreperfusion. CS and RS were measured using speckle tracking echocardiography. Subsequently, the pigs were sacrificed, and histological analysis for infarct size was performed.
  
  
  RESULTS
  After 90-minute occlusion, reduced strains were detected for all segments (infarcted anterior wall - baseline: CS: -17.6 ± 5.7%, RS: 54.4 ± 16.9%; 90 min: CS: -10.3 ± 3.0%, RS: 23.3 ± 7.0%; tethered posterior wall - baseline: CS: -18.4 ± 3.5%, RS: 68.7 ± 21.1%; 90 min: CS: -10.7 ± 6.4%, RS: 34.5 ± 14.7%, P < 0.001). However, postsystolic shortening was detected only in the infarcted segments, and the time-to-peak CS was 25% longer (P < 0.05). At 30 and 60 days postreperfusion, time-to-peak CS could only detect large scars in the anterior and anterior-septum walls (P < 0.05), while peak CS also detected smaller scars in the lateral wall (P < 0.05). RS failed to distinguish between normal, stunned/tethered, and infarcted myocardium.
  
  
  CONCLUSIONS
  During occlusion and 2 hours postreperfusion, time-to-peak CS could distinguish between infarcted and stunned/tethered myocardial segments, while at 30 and 60 days postreperfusion, peak CS was the best detector of infarction.
authors.affiliation: Analyze IT Research Institute, Tuval, Israel.
authors.forename: Noa
authors.initials: N
authors.lastname: Bachner-Hinenzon
authors.affiliation: Department of Physiology, Technion, Haifa, Israel.|Rappaport Faculty of Medicine, Technion, Haifa, Israel.
authors.forename: Assaf
authors.initials: A
authors.lastname: Malka
authors.affiliation: Department of Cardiothoracic Surgery, Rabin Medical Center, Petah Tikva, Israel.
authors.forename: Yaron
authors.initials: Y
authors.lastname: Barac
authors.affiliation: Department of Cardiology, Shaare Zedek Medical Center, Jerusalem, Israel.
authors.forename: David
authors.initials: D
authors.lastname: Meerkin
authors.affiliation: Eliachar Research Laboratory, Medical Center of the Galilee, Nahariya, Israel.
authors.forename: Offir
authors.initials: O
authors.lastname: Ertracht
authors.affiliation: Faculty of Medicine, Bar-Ilan University, Tzfat, Israel.|Poriya Medical Center, Lower Galilee, Israel.
authors.forename: Shemy
authors.initials: S
authors.lastname: Carasso
authors.affiliation: Rappaport Faculty of Medicine, Technion, Haifa, Israel.
authors.forename: Rona
authors.initials: R
authors.lastname: Shofti
authors.affiliation: Department of Cardiology, Assaf Harofeh Medical Center, Zerifin, Israel.|Sackler School of Medicine, Tel Aviv University, Tel Aviv, Israel.
authors.forename: Marina
authors.initials: M
authors.lastname: Leitman
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: Faculty of Biomedical Engineering, Technion, Haifa, Israel.
authors.forename: Dan
authors.initials: D
authors.lastname: Adam
authors.affiliation: Department of Physiology, Technion, Haifa, Israel.|Rappaport Faculty of Medicine, Technion, Haifa, Israel.
authors.forename: Ofer
authors.initials: O
authors.lastname: Binah
mesh_terms: D000208:Acute Disease; D000818:Animals; D002908:Chronic Disease; D018450:Disease Progression; D004452:Echocardiography / Q000379:methods*; D054459:Elasticity Imaging Techniques / Q000379:methods*; D007089:Image Enhancement / Q000379:methods; D007090:Image Interpretation, Computer-Assisted / Q000379:methods*; D008297:Male; D009203:Myocardial Infarction / Q000000981:diagnostic imaging* / Q000503:physiopathology*; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D013552:Swine
keywords: ischemia; myocardial infarction; speckle tracking echocardiography; stunning; viability