title: Assessment of myocardial ischemic memory using speckle tracking echocardiography.
abstract: OBJECTIVE
  The aim of this study was to evaluate which regional myocardial parameters derived from speckle tracking echocardiography could demonstrate myocardial ischemic memory in a brief ischemia-reperfusion dog model.
  
  
  BACKGROUND
  Myocardial ischemic memory imaging, denoting the visualization of abnormalities provoked by ischemia and sustained even after restoration of perfusion, can convey important clinical information. We previously reported that post-systolic shortening (PSS) remains in the risk area after recovery from brief ischemia. However, it is still unclear whether abnormalities in other regional deformation parameters persist after relief from brief ischemia.
  
  
  METHODS
  Echocardiographic data were chronologically acquired from 11 dogs during 2 min of coronary occlusion followed by reperfusion. Regional systolic and diastolic deformation parameters, including parameters related to PSS, were measured from radial and circumferential strain and from strain rate analyzed in the risk and normal areas. Strain imaging diastolic index (SI-DI), which had been proposed as a parameter for assessing ischemic memory, was also calculated.
  
  
  RESULTS
  Peak systolic strain, end-systolic strain, and peak systolic strain rate decreased in the risk area during occlusion but recovered to the baseline level immediately after reperfusion. Strain rate during early diastole decreased during occlusion; however, the decrease did not persist after reperfusion. Post-systolic strain index (PSI) and time-to-peak strain index, which are parameters of PSS, increased during occlusion. These increases persisted until 10 to 20 min after reperfusion (circumferential PSI: 0.02 ± 0.04 [baseline] vs. 0.08 ± 0.04 [20 min], p < 0.05). SI-DI did not show a significant change during occlusion because of a large variation.
  
  
  CONCLUSIONS
  Although abnormalities of PSS-related parameters alone persisted after recovery from 2-min occlusion, abnormalities of other deformation parameters, such as strain rate during early diastole, did not. These data suggest that assessment of PSS by speckle tracking echocardiography is useful for detecting myocardial ischemic memory.
authors.affiliation: Division of Functional Diagnostics, Department of Health Sciences, Osaka University Graduate School of Medicine, Suita, Osaka, Japan. toshi@sahs.med.osaka-u.ac.jp
authors.forename: Toshihiko
authors.initials: T
authors.lastname: Asanuma
authors.forename: Yumi
authors.initials: Y
authors.lastname: Fukuta
authors.forename: Kasumi
authors.initials: K
authors.lastname: Masuda
authors.forename: Ayana
authors.initials: A
authors.lastname: Hioki
authors.forename: Mariko
authors.initials: M
authors.lastname: Iwasaki
authors.forename: Satoshi
authors.initials: S
authors.lastname: Nakatani
mesh_terms: D000818:Animals; D001696:Biomechanical Phenomena; D004195:Disease Models, Animal; D004285:Dogs; D004452:Echocardiography / Q000379:methods*; D006352:Heart Ventricles / Q000000981:diagnostic imaging* / Q000503:physiopathology; D006439:Hemodynamics; D009200:Myocardial Contraction; D017202:Myocardial Ischemia / Q000000981:diagnostic imaging* / Q000503:physiopathology; D015428:Myocardial Reperfusion Injury / Q000000981:diagnostic imaging* / Q000503:physiopathology; D011237:Predictive Value of Tests; D013997:Time Factors; D016277:Ventricular Function, Left