title: A theoretical cardiac resynchronization therapy method to augment ventricular contraction using polymer-based actuators and mitral regurgitation reduction with devices over left ventricular endocardial pacing wire--an in-vitro study.
abstract: BACKGROUND
  To investigate a potential cardiac resynchronization method using high force density actuators and mitral regurgitation (MR) reduction devices.
  
  
  METHODS
  An 8-cm long, 0.4-mm thick, and 2-mm wide polymeric actuator strip was attached to the right ventricular (RV) pacemaker lead 4.0 cm from the edge of the leads, and 035 wire and step-up voltages (2-9 V) were given. Deformation of the pacemaker lead with polymer was studied under cine-fluoroscopy in the air and immersing it in 0.9% saline. Cantilever function was assessed by the addition of gold rings. The left ventricular (LV) lead was reinforced with dual polymer and a side branching 035 wire Y-attachment and studied. A novel nitinol-based Gore-Tex device and polymer-based technology was developed and positioned abutting the mitral valves, and was evaluated in sheep heart preparations by cine-fluoroscopy.
  
  
  RESULTS
  The mean deformation at 9 V for the LV leads, RV leads, and 035 wires was 3.5 ± 0.2 mm, 1.1 ± 0.1 mm, and 1.4 ± 0.1 mm, respectively, and the stopping weight was 3.8 ± 0.2 g, 3.2 ± 0.1 g, and 3.6 ± 0.3 g, respectively. With dual surfacing of polymer and driven by separate actuation circuits simultaneously, the stopping weight parameters increased to 4.8 ± 0.2 g, 4.0 ± 0.2 g, and 4.6 ± 0.1 g, respectively (>25% each; P<.01 for all). The nitinol-based Gore-Tex device and the polymer device appeared to have reduced MR significantly from grade IV to grade I (>60% by visual quantification).
  
  
  CONCLUSIONS
  There is potential for a novel theoretical cardiac resynchronization therapy method using polymer-based actuators and devices to control MR.
authors.affiliation: Pondicherry Institute of Medical Sciences, Kalathumettupathai, Kalapet, Pondicherry 605014, India. christomark@gmail.com
authors.forename: Mark
authors.initials: M
authors.lastname: Arokiaraj
authors.forename: Luis
authors.initials: L
authors.lastname: Guerrero
authors.forename: Robert
authors.initials: R
authors.lastname: Levine
authors.forename: Igor
authors.initials: I
authors.lastname: Palacios
mesh_terms: D000818:Animals; D058406:Cardiac Resynchronization Therapy / Q000379:methods*; D004195:Disease Models, Animal; D006333:Heart Failure / Q000628:therapy*; D006352:Heart Ventricles / Q000503:physiopathology; D066298:In Vitro Techniques; D008944:Mitral Valve Insufficiency / Q000517:prevention & control*; D010138:Pacemaker, Artificial; D011108:Polymers; D011580:Psychological Techniques; D012756:Sheep; D016896:Treatment Outcome; D018754:Ventricular Dysfunction / Q000503:physiopathology / Q000628:therapy*
chemical_list: D011108:Polymers