title: Analysis of temporal delay in myocardial deformation throughout the cardiac cycle: utility for selecting candidates for cardiac resynchronization therapy.
abstract: BACKGROUND
  Analysis of myocardial strain using two-dimensional (2D) echocardiography to assess left ventricular (LV) mechanical dyssynchrony by measuring time differences in peak systolic strains from opposing LV walls has been proposed. However, peak systolic strain may be difficult to identify.
  
  
  OBJECTIVE
  The purpose of this study was to evaluate (1) LV dyssynchrony by assessing the overlap among strain traces of the LV walls throughout the cardiac cycle and (2) its usefulness in identifying responders to cardiac resynchronization therapy (CRT).
  
  
  METHODS
  Fifty patients with heart failure and LV systolic dysfunction undergoing CRT were studied with 2D echocardiography at baseline and 6-month follow-up. Myocardial radial strain and circumferential strain were analyzed using commercially available software. The resulting strain traces were postprocessed with a mathematical script.
  
  
  RESULTS
  Quantification of LV dyssynchrony was expressed as an index of temporal overlap from the analyzed traces. Responders to CRT were defined by ≥15% reduction of LV end-systolic volume at 6-month follow-up. Responders to CRT had higher LV dyssynchrony in both radial strain and circumferential strain analysis. A cutoff time overlap ≥7% for radial strain (area under the curve 0.79) and ≥8.5% for circumferential strain (area under the curve 0.66) identified responders to CRT.
  
  
  CONCLUSIONS
  Quantifying the temporal superposition of LV wall deformations with a computed algorithm allows measurement of LV intraventricular dyssynchrony throughout the cardiac cycle. The derived index is useful in stratifying the probability of response to CRT.
authors.affiliation: Thorax Institute, Hospital Clínic, IDIBAPS-Institut d'Investigacions Biomèdiques August Pi i Sunyer, University of Barcelona, Barcelona, Spain.
authors.forename: Etelvino
authors.initials: E
authors.lastname: Silva
authors.forename: Marta
authors.initials: M
authors.lastname: Sitges
authors.forename: Adelina
authors.initials: A
authors.lastname: Doltra
authors.forename: Lluis
authors.initials: L
authors.lastname: Mont
authors.forename: Barbara
authors.initials: B
authors.lastname: Vidal
authors.forename: M Angeles
authors.initials: MA
authors.lastname: Castel
authors.forename: J María
authors.initials: JM
authors.lastname: Tolosana
authors.forename: Antonio
authors.initials: A
authors.lastname: Berruezo
authors.forename: J Ramon
authors.initials: JR
authors.lastname: González Juanatey
authors.forename: Josep
authors.initials: J
authors.lastname: Brugada
mesh_terms: D000368:Aged; D058406:Cardiac Resynchronization Therapy; D004452:Echocardiography; D005260:Female; D006333:Heart Failure / Q000000981:diagnostic imaging* / Q000628:therapy*; D006801:Humans; D008297:Male; D008875:Middle Aged; D009200:Myocardial Contraction; D009206:Myocardium / Q000473:pathology; D018487:Ventricular Dysfunction, Left / Q000000981:diagnostic imaging* / Q000628:therapy*