title: Apical rotation assessed by speckle-tracking echocardiography as an index of global left ventricular contractility.
abstract: BACKGROUND
  Left ventricular (LV) apical rotation and twist can be estimated noninvasively by speckle-tracking echocardiography (STE). In this study, we tested whether apical rotation is an accurate index of LV contractility.
  
  
  RESULTS
  We measured LV basal and apical rotation by STE in 11 open-chest anesthetized mongrel dogs under 8 different inotropic stages before and after ligation of either left anterior descending (n=6) or circumflex coronary artery (n=5). We measured LV pressure simultaneously with a high-fidelity pressure catheter and calculated LV ejection fraction (EF) with the biplane Simpson method and 2D echocardiography. Maximal positive dP/dt (dP/dt(max)) was used as the gold standard measurement of LV contractility. We compared LV twist and apical rotation and EF against dP/dt(max) by linear mixed model. LV apical rotation and twist showed dose-dependent increases and decreases after dobutamine and esmolol infusion, respectively. However, basal rotation did not change significantly during different inotropic conditions. There was a stronger association between dP/dt(max) and LV twist (R(2)=0.747, P<0.001) and apical rotation (R(2)=0.726, P<0.001) than between dP/dt(max) and EF (R(2)=0.408, P<0.001), and this trend was more apparent with coronary ligation irrespective of the ligation site. There was also a high association between dP/dt(max) and apical rotation alone, both with (R(2)=0.805, P<0.001) and without (R(2)=0.748, P<0.001) coronary ligation. Apical rotation alone showed comparable accuracy to LV twist. Apical rotational velocity also showed a high association with dP/dt(max) (R(2)=0.669, P<0.001) and LV twist (R(2)=0.892, P<0.001).
  
  
  CONCLUSIONS
  Apical rotation assessed by STE is an effective noninvasive index of global LV contractility and is more closely related to dP/dt(max) than LV EF.
authors.affiliation: Cardiology and Laboratory of Animal Research, Asan Medical Center, University of Ulsan College of Medicine, Seoul, South Korea.
authors.forename: Won-Jang
authors.initials: WJ
authors.lastname: Kim
authors.forename: Byeong Han
authors.initials: BH
authors.lastname: Lee
authors.forename: Yun Jeong
authors.initials: YJ
authors.lastname: Kim
authors.forename: Jee Hye
authors.initials: JH
authors.lastname: Kang
authors.forename: Yoo Jin
authors.initials: YJ
authors.lastname: Jung
authors.forename: Jong-Min
authors.initials: JM
authors.lastname: Song
authors.forename: Duk-Hyun
authors.initials: DH
authors.lastname: Kang
authors.forename: Jae-Kwan
authors.initials: JK
authors.lastname: Song
mesh_terms: D000319:Adrenergic beta-Antagonists / Q000494:pharmacology; D000818:Animals; D002316:Cardiotonic Agents / Q000494:pharmacology; D004280:Dobutamine / Q000494:pharmacology; D004285:Dogs; D004305:Dose-Response Relationship, Drug; D004452:Echocardiography; D009200:Myocardial Contraction / Q000187:drug effects; D011412:Propanolamines / Q000494:pharmacology; D054159:Torsion, Mechanical; D016277:Ventricular Function, Left / Q000187:drug effects
chemical_list: D000319:Adrenergic beta-Antagonists; D002316:Cardiotonic Agents; D011412:Propanolamines; D004280:Dobutamine; C036604:esmolol