title: Myocardial motion and deformation patterns in an experimental swine model of acute LBBB/CRT and chronic infarct.
abstract: In cardiac resynchronization therapy (CRT), specific changes in motion/deformation happen with left-bundle-branch-block (LBBB) and following treatment. However, they remain sub-optimally studied. We propose a two-fold improvement of their characterization. This includes controlling them through an experimental model and using more suitable quantification techniques. We used a swine model of acute LBBB and CRT with/without chronic infarct (pure-LBBB: N = 11; LBBB + left-anterior-descending infarct: N = 11). Myocardial displacement, velocity and strain were extracted from short-axis echocardiographic sequences using 2D speckle-tracking. The data was transformed to a single spatiotemporal system of coordinates to perform subject comparisons and quantify pattern changes at similar locations and instants. Pure-LBBB animals showed a specific intra-ventricular dyssynchrony pattern with LBBB (11/11 animals), and the recovery towards a normal pattern with CRT (10/11 animals). Pattern variability was low within the pure-LBBB population, as quantified by our method. This was not correctly assessed by more conventional measurements. Infarct presence affected the pattern distribution and CRT efficiency (improvements in 6/11 animals). Pattern changes correlated with global cardiac function (global circumferential strain) changes in all the animals (corrected: (pLBBBvsBaseline) < 0.001, (pCRTvsBaseline) = NS; non-corrected: (pLBBBvsBaseline) = NS, (pCRTvsBaseline) = 0.028). Our LBBB/CRT experimental model allowed controlling specific factors responsible for changes in mechanical dyssynchrony and therapy. We illustrated the importance of our quantification method to study these changes and their variability. Our findings confirm the importance of myocardial viability and of specific LBBB-related mechanical dyssynchrony patterns.
authors.affiliation: Arrythmia, Resynchronization and Cardiac Imaging Unit, Hospital Clínic, Universitat de Barcelona, Calle Villaroel 170, 08036, Barcelona, Spain, n.duchateaucistib@gmail.com.
authors.forename: Nicolas
authors.initials: N
authors.lastname: Duchateau
authors.forename: Marta
authors.initials: M
authors.lastname: Sitges
authors.forename: Adelina
authors.initials: A
authors.lastname: Doltra
authors.forename: Juan
authors.initials: J
authors.lastname: Fernández-Armenta
authors.forename: Nuria
authors.initials: N
authors.lastname: Solanes
authors.forename: Montserrat
authors.initials: M
authors.lastname: Rigol
authors.forename: Luigi
authors.initials: L
authors.lastname: Gabrielli
authors.forename: Etelvino
authors.initials: E
authors.lastname: Silva
authors.forename: Aina
authors.initials: A
authors.lastname: Barceló
authors.forename: Antonio
authors.initials: A
authors.lastname: Berruezo
authors.forename: Lluís
authors.initials: L
authors.lastname: Mont
authors.forename: Josep
authors.initials: J
authors.lastname: Brugada
authors.forename: Bart
authors.initials: B
authors.lastname: Bijnens
mesh_terms: D000208:Acute Disease; D000818:Animals; D002037:Bundle-Branch Block / Q000503:physiopathology* / Q000628:therapy*; D058406:Cardiac Resynchronization Therapy / Q000379:methods*; D002908:Chronic Disease; D004195:Disease Models, Animal; D004452:Echocardiography; D007090:Image Interpretation, Computer-Assisted; D008279:Magnetic Resonance Imaging; D009203:Myocardial Infarction / Q000000981:diagnostic imaging / Q000503:physiopathology*; D013552:Swine