title: Cardiac resynchronization therapy by multipoint pacing improves response of left ventricular mechanics and fluid dynamics: a three-dimensional and particle image velocimetry echo study.
abstract: OBJECTIVE
  To characterize the effect of multipoint pacing (MPP) compared to biventricular pacing (BiV) on left ventricle (LV) mechanics and intraventricular fluid dynamics by three-dimensional echocardiography (3DE) and echocardiographic particle imaging velocimetry (Echo-PIV).
  
  
  RESULTS
  In 11 consecutive patients [8 men; median age 65 years (57-75)] receiving cardiac resynchronization therapy (CRT) with a quadripolar LV lead (Quartet,St.Jude Medical,Inc.), 3DE and Echo-PIV data were collected for each pacing configuration (CRT-OFF, BiV, and MPP) at follow-up after 6 months. 3DE data included LV volumes, LV ejection fraction (LVEF), strain, and systolic dyssynchrony index (SDI). Echo-PIV was used to evaluate the directional distribution of global blood flow momentum, ranging from zero, when flow force is predominantly along the base-apex direction, up to 90° when it becomes transversal. MPP resulted in significant reduction in end-diastolic and end-systolic volumes compared with both CRT-OFF (P = 0.02; P = 0.008, respectively) and BiV (P = 0.04; P = 0.03, respectively). LVEF and cardiac output were significant superior in MPP compared with CRT-OFF, but similar between MPP and BiV. Statistical significant differences when comparing global longitudinal and circumferential strain and SDI with MPP vs. CRT-OFF were observed (P = 0.008; P = 0.008; P = 0.01, respectively). There was also a trend towards improvement in strain between BiV and MPP that did not reach statistical significance. MPP reflected into a significant reduction of the deviation of global blood flow momentum compared with both CRT-OFF and BiV (P = 0.002) indicating a systematic increase of longitudinal alignment from the base-apex orientation of the haemodynamic forces.
  
  
  CONCLUSIONS
  These preliminary results suggest that MPP resulted in significant improvement of LV mechanics and fluid dynamics compared with BiV. However, larger studies are needed to confirm this hypothesis.
authors.affiliation: Department of Cardiac, Thoracic and Vascular Sciences, University of Padova, Via Giustiniani 2, 35121 Padova, Italy.
authors.forename: Mariachiara
authors.initials: M
authors.lastname: Siciliano
authors.affiliation: Department of Cardiac, Thoracic and Vascular Sciences, University of Padova, Via Giustiniani 2, 35121 Padova, Italy.
authors.forename: Federico
authors.initials: F
authors.lastname: Migliore
authors.affiliation: Department of Cardiac, Thoracic and Vascular Sciences, University of Padova, Via Giustiniani 2, 35121 Padova, Italy.
authors.forename: Luigi
authors.initials: L
authors.lastname: Badano
authors.affiliation: Department of Cardiac, Thoracic and Vascular Sciences, University of Padova, Via Giustiniani 2, 35121 Padova, Italy.
authors.forename: Emanuele
authors.initials: E
authors.lastname: Bertaglia
authors.affiliation: Department of Engineering and Architecture, University of Trieste, P. Europa 1, 34127 Trieste, Italy.
authors.forename: Gianni
authors.initials: G
authors.lastname: Pedrizzetti
authors.affiliation: Department of Cardiac, Thoracic and Vascular Sciences, University of Padova, Via Giustiniani 2, 35121 Padova, Italy.
authors.forename: Stefano
authors.initials: S
authors.lastname: Cavedon
authors.affiliation: Department of Cardiac, Thoracic and Vascular Sciences, University of Padova, Via Giustiniani 2, 35121 Padova, Italy.
authors.forename: Alessandro
authors.initials: A
authors.lastname: Zorzi
authors.affiliation: Department of Cardiac, Thoracic and Vascular Sciences, University of Padova, Via Giustiniani 2, 35121 Padova, Italy.
authors.forename: Domenico
authors.initials: D
authors.lastname: Corrado
authors.affiliation: Department of Cardiac, Thoracic and Vascular Sciences, University of Padova, Via Giustiniani 2, 35121 Padova, Italy.
authors.forename: Sabino
authors.initials: S
authors.lastname: Iliceto
authors.affiliation: Department of Cardiac, Thoracic and Vascular Sciences, University of Padova, Via Giustiniani 2, 35121 Padova, Italy.
authors.forename: Denisa
authors.initials: D
authors.lastname: Muraru
mesh_terms: D000368:Aged; D001696:Biomechanical Phenomena; D058406:Cardiac Resynchronization Therapy / Q000009:adverse effects / Q000379:methods*; D058409:Cardiac Resynchronization Therapy Devices; D018619:Echocardiography, Doppler, Pulsed; D019560:Echocardiography, Three-Dimensional; D005260:Female; D006333:Heart Failure / Q000000981:diagnostic imaging / Q000503:physiopathology / Q000628:therapy*; D006801:Humans; D057446:Hydrodynamics; D007090:Image Interpretation, Computer-Assisted; D008297:Male; D008875:Middle Aged; D008955:Models, Cardiovascular; D009200:Myocardial Contraction; D066230:Patient-Specific Modeling; D011237:Predictive Value of Tests; D000074286:Preliminary Data; D013318:Stroke Volume; D013997:Time Factors; D016896:Treatment Outcome; D018487:Ventricular Dysfunction, Left / Q000000981:diagnostic imaging / Q000503:physiopathology / Q000628:therapy*; D016277:Ventricular Function, Left
keywords: 3D echocardiography; Cardiac fluid mechanics; Cardiac resynchronization therapy; Heart failure; Multipoint pacing; Particle image velocimetry