title: Energy loss in the left ventricle obtained by vector flow mapping as a new quantitative measure of severity of aortic regurgitation: a combined experimental and clinical study.
abstract: OBJECTIVE
  In aortic regurgitation (AR), energy loss (EL) produced by inefficient turbulent flow may be a burden to the heart predicting decompensation. We attempted to quantify EL in AR induced in an acute dog model and in patients with chronic AR using novel echocardiographic method vector flow mapping (VFM).
  
  
  RESULTS
  In 11 anaesthetized open-chest dogs, AR was induced by distorting the aortic valve with a pigtail catheter, in totally 20 cases. Regurgitant fraction was determined using pulsed Doppler echocardiography, <30% considered mild to moderate (Group 1, n = 11) and ≥30% moderate to severe (Group 2, n = 9). The clinical study consisted of 22 patients with various degrees of AR; 11 mild to moderate (Group 1) and 11 moderate to severe (Group 2), and compared with 12 normals. VFM is based on continuity equation applied to colour Doppler and speckle tracking velocities, acquired from apical long-axis image. EL was calculated frame by frame, averaged from three beats. In the dog study, diastolic EL increased significantly with severity of AR (baseline vs. Group 1 vs. Group 2: 3.8 ± 1.6 vs. 13.0 ± 5.0 vs. 22.4 ± 14.0 [J/(m s)], ANOVA P = 0.0001). Similar to dogs, diastolic EL also increased in humans by the severity of AR (control vs. Group 1 vs. Group 2: 2.8 ± 1.5 vs. 14.3 ± 11.5 vs. 18.6 ± 2.3 [J/(m s)], ANOVA P = 0.001).
  
  
  CONCLUSIONS
  VFM provides a promising method to quantify diastolic EL in AR. Diastolic EL increases in AR proportional to its severity. EL may be useful to determine the severity of disease from the aspect of cardiac load.
authors.affiliation: Osaka University Graduate School of Medicine, Suita, Japan.
authors.forename: Marie
authors.initials: M
authors.lastname: Stugaard
authors.affiliation: Osaka University Graduate School of Medicine, Suita, Japan.
authors.forename: Hikaru
authors.initials: H
authors.lastname: Koriyama
authors.affiliation: Osaka University Hospital, Suita, Japan.
authors.forename: Keiko
authors.initials: K
authors.lastname: Katsuki
authors.affiliation: Osaka University Graduate School of Medicine, Suita, Japan.
authors.forename: Kasumi
authors.initials: K
authors.lastname: Masuda
authors.affiliation: Osaka University Graduate School of Medicine, Suita, Japan.
authors.forename: Toshihiko
authors.initials: T
authors.lastname: Asanuma
authors.affiliation: Osaka University Hospital, Suita, Japan.
authors.forename: Yasuharu
authors.initials: Y
authors.lastname: Takeda
authors.affiliation: Osaka University Hospital, Suita, Japan.
authors.forename: Yasushi
authors.initials: Y
authors.lastname: Sakata
authors.affiliation: Kitasato University School of Medicine, Sagamihara, Japan.
authors.forename: Keiichi
authors.initials: K
authors.lastname: Itatani
authors.affiliation: Osaka University Graduate School of Medicine, Suita, Japan nakatani@sahs.med.osaka-u.ac.jp.
authors.forename: Satoshi
authors.initials: S
authors.lastname: Nakatani
mesh_terms: D000328:Adult; D000368:Aged; D000704:Analysis of Variance; D000818:Animals; D001022:Aortic Valve Insufficiency / Q000000981:diagnostic imaging* / Q000503:physiopathology; D016022:Case-Control Studies; D004195:Disease Models, Animal; D004285:Dogs; D018619:Echocardiography, Doppler, Pulsed / Q000379:methods*; D005260:Female; D006801:Humans; D007091:Image Processing, Computer-Assisted; D008875:Middle Aged; D012016:Reference Values; D012720:Severity of Illness Index; D013318:Stroke Volume / Q000502:physiology; D014672:Vectorcardiography / Q000379:methods; D018487:Ventricular Dysfunction, Left / Q000000981:diagnostic imaging*