title: Novel area strain based on three-dimensional wall motion analysis for assessment of global left ventricular performance after repair of tetralogy of Fallot.
abstract: OBJECTIVE
  This study aimed to determine the usefulness of novel parameters of left ventricular (LV) endocardial area strain (AS) in assessing global LV performance in patients with repaired tetralogy of Fallot (TOF).
  
  
  METHODS
  Thirty patients, aged 21.7 ± 5.8 years, with repaired TOF and 25 healthy subjects aged 19.9 ± 5.5 years were studied. Three-dimensional LV wall motion tracking was performed to determine global and regional peak AS, an AS-systolic dyssynchrony index (SDI), and LV volumes and ejection fraction. The AS-SDI was derived from the dispersion of time-to-minimum segmental endocardial areas, expressed as a percentage of RR interval, using a 16-segment model. The LV global performance plot was generated by plotting peak global AS against AS-SDI.
  
  
  RESULTS
  The coefficients of variations for intra- and interobserver measurement of LV global AS were 6.3% and 10.6%, respectively. Compared with controls, patients had significantly lower global AS (30.5% ± 4.5% vs. 40.9% ± 2.8%, P < .001) and greater AS-SDI (10.0% ± 2.9% vs. 4.1% ± 1.4%, P < .001). Global AS (r = 0.94, P < .001) and AS-SDI (r = -0.76, P < .001) correlated strongly with LV ejection fraction. The global performance plot identified 87% of patients (26/30) with both reduced LV global AS and LV systolic mechanical dyssynchrony.
  
  
  CONCLUSIONS
  AS measurement of LV endocardium based on three-dimensional wall motion tracking is reproducible and enables convenient assessment of global LV performance using a composite representation of parameters, including global AS and an AS-derived index of mechanical dyssynchrony.
authors.affiliation: Division of Paediatric Cardiology, Department of Paediatrics and Adolescent Medicine, Queen Mary Hospital, The University of Hong Kong, Hong Kong, China.
authors.forename: Shu-na
authors.initials: SN
authors.lastname: Li
authors.forename: Sophia J
authors.initials: SJ
authors.lastname: Wong
authors.forename: Yiu-fai
authors.initials: YF
authors.lastname: Cheung
mesh_terms: D000293:Adolescent; D000328:Adult; D000465:Algorithms; D006348:Cardiac Surgical Procedures; D016022:Case-Control Studies; D019560:Echocardiography, Three-Dimensional; D005260:Female; D006352:Heart Ventricles / Q000000981:diagnostic imaging* / Q000503:physiopathology; D006801:Humans; D008297:Male; D009200:Myocardial Contraction; D018570:Risk Assessment; D013318:Stroke Volume; D013599:Systole; D013771:Tetralogy of Fallot / Q000000981:diagnostic imaging* / Q000503:physiopathology / Q000601:surgery; D016896:Treatment Outcome