title: Non-blood contacting biventricular support for severe heart failure.
abstract: BACKGROUND
  Direct mechanical ventricular actuation (DMVA) is a non-blood contacting method of biventricular support. DMVA employs a vacuum attached, pneumatically regulated, flexible membrane to transfer both systolic and diastolic forces to the ventricular myocardium. The purpose of this study was to determine if DMVA effectively restores pump performance when applied to the severely failing heart.
  
  
  METHODS
  Bovines (n = 10) underwent thoracotomy and were instrumented for continuous hemodynamic monitoring. Cardiac failure was induced by beta1-blockade to achieve a cardiac index of < 1.5 l/min/m2 for 1 hour. Heart rate was maintained at 100 bpm by atrioventricular sequential pacing. Synchronous DMVA support was then applied for 3 hours.
  
  
  RESULTS
  Eight animals achieved significant reductions in cardiac index and mean arterial pressures (35%* and 43%* control, respectively; *p < 0.05). DMVA restored cardiac index to baseline and significantly increased arterial pressures (p < 0.05; DMVA versus cardiac failure). Pulmonary flow and mean pulmonary artery pressures were similar to baseline during DMVA (p = NS). Pathologic exam did not demonstrate evidence of significant device trauma.
  
  
  CONCLUSIONS
  DMVA support can effectively restore pump performance of the acutely failing heart. Synchronization may be inherent to the stimulus of cardiac compression. These data further substantiate DMVA's potential as an adjunct to the field of circulatory support.
authors.affiliation: The Michael E. DeBakey Department of Surgery, Baylor College of Medicine, Houston, Texas, USA. manstadt@mail.mcg.edu
authors.forename: Mark P
authors.initials: MP
authors.lastname: Anstadt
authors.forename: Sebastian A
authors.initials: SA
authors.lastname: Schulte-Eistrup
authors.forename: Tadashi
authors.initials: T
authors.lastname: Motomura
authors.forename: Ernesto R
authors.initials: ER
authors.lastname: Soltero
authors.forename: Tamaki
authors.initials: T
authors.lastname: Takano
authors.forename: Issam A
authors.initials: IA
authors.lastname: Mikati
authors.forename: Kenji
authors.initials: K
authors.lastname: Nonaka
authors.forename: Fernando
authors.initials: F
authors.lastname: Joglar
authors.forename: Yukihiko
authors.initials: Y
authors.lastname: Nosé
mesh_terms: D000818:Animals; D002417:Cattle; D004562:Electrocardiography; D004699:Endocardium / Q000473:pathology; D004867:Equipment Design; D019544:Equipment Failure Analysis; D006333:Heart Failure / Q000473:pathology / Q000503:physiopathology / Q000628:therapy*; D006352:Heart Ventricles / Q000503:physiopathology; D006353:Heart-Assist Devices; D006439:Hemodynamics / Q000502:physiology; D009206:Myocardium / Q000473:pathology