title: Assessment of left ventricular function long term after arterial switch operation for transposition of the great arteries by dobutamine stress echocardiography.
abstract: OBJECTIVE
  To use dobutamine stress echocardiography to determine left ventricular (LV) function and wall motion of children long term after arterial switch operation (ASO) for transposition of the great arteries.
  
  
  METHODS
  31 patients (24 boys) with ASO performed at a mean (SD) of 15.5 (4.3) days of life were studied at an age of 9.4 (2.0) years. All had normal coronary angiographic findings. LV echocardiographic indexes, including fractional shortening, ejection fraction, rate corrected velocity of circumferential fibre shortening (VCFc), and wall stress, as well as LV wall motion abnormalities were determined at rest and under dobutamine stress. The results were compared with those of 20 healthy age matched control participants.
  
  
  METHODS
  Tertiary paediatric cardiac centre.
  
  
  RESULTS
  Fractional shortening, ejection fraction, and VCFc were significantly lower in patients than in controls at rest (all with p < 0.001). Stress-velocity index detected impaired LV contractility in 19 (61%) patients at rest. An older age at operation (p = 0.01), longer bypass (p = 0.01) and circulatory arrest times (p = 0.045), and an unusual coronary artery pattern (p = 0.059) were associated with impaired resting LV contractility. Dobutamine stress echocardiography unmasked wall motion abnormalities in 23 (74%) patients. Exercise myocardial perfusion scan, performed in 22 patients, showed reversible myocardial perfusion defects in 17. These defects corresponded to segments of hypokinesia as detected by dobutamine stress echocardiography.
  
  
  CONCLUSIONS
  A significant proportion of children, albeit asymptomatic, had impaired baseline LV contractility and reversible myocardial perfusion defects and mild wall motion abnormalities on stress after ASO.
authors.affiliation: Division of Paediatric Cardiology, Grantham Hospital, The University of Hong Kong, Hong Kong, People's Republic of China.
authors.forename: L
authors.initials: L
authors.lastname: Hui
authors.forename: A K T
authors.initials: AK
authors.lastname: Chau
authors.forename: M P
authors.initials: MP
authors.lastname: Leung
authors.forename: C S W
authors.initials: CS
authors.lastname: Chiu
authors.forename: Y F
authors.initials: YF
authors.lastname: Cheung
mesh_terms: D000293:Adolescent; D002648:Child; D025401:Echocardiography, Stress / Q000379:methods*; D005080:Exercise Test / Q000379:methods; D005260:Female; D005500:Follow-Up Studies; D006346:Heart Septum / Q000503:physiopathology; D006439:Hemodynamics; D006801:Humans; D008297:Male; D011183:Postoperative Complications / Q000000981:diagnostic imaging*; D011877:Radionuclide Imaging; D012307:Risk Factors; D013599:Systole; D014188:Transposition of Great Vessels / Q000503:physiopathology / Q000601:surgery*; D018487:Ventricular Dysfunction, Left / Q000000981:diagnostic imaging* / Q000209:etiology; D016277:Ventricular Function, Left