title: MagScrew total artificial heart in vivo performance above 200 beats per minute.
abstract: OBJECTIVE
  Downsizing pulsatile devices requires an increase of beat rate if flow capacity is to be maintained. We applied this concept to the preclinical MagScrew total artificial heart (TAH).
  
  
  METHODS
  The device fills passively with a stroke volume of 45 ml and beat rates up to 250 beats per minute (bpm).
  
  
  RESULTS
  Stable hemodynamics were observed during a 30-day bovine implant with a flow of 8.7 +/- 1.2 L/min at beat rates of 204 +/- 18 bpm. Device filling was exceptional up to 250 bpm generating flow of greater than 12 L/min. Beat rate adapted to preload in a way similar to a Frank-Starling response. Left and right atrial pressures were balanced. The aortic pulse pressure was 49-70 mm Hg, which translates to a pulsatility index of 0.49-0.77. Organ functions were preserved and blood damage did not occur.
  
  
  CONCLUSIONS
  Increasing the beat rate while downsizing the MagScrew TAH was successful with strong flow generation by passive filling. Pulsatility was maintained at high beat rates. This innovative approach may be used to develop small pulsatile pumps.
authors.affiliation: Department of Biomedical Engineering, The Cleveland Clinic Foundation, Cleveland, Ohio 44195, USA.
authors.forename: Soren
authors.initials: S
authors.lastname: Schenk
authors.forename: Stephan
authors.initials: S
authors.lastname: Weber
authors.forename: Viviane
authors.initials: V
authors.lastname: Luangphakdy
authors.forename: Ryan S
authors.initials: RS
authors.lastname: Klatte
authors.forename: Christine R
authors.initials: CR
authors.lastname: Flick
authors.forename: Ji-Feng
authors.initials: JF
authors.lastname: Chen
authors.forename: Michael W
authors.initials: MW
authors.lastname: Kopcak
authors.forename: Yoshio
authors.initials: Y
authors.lastname: Ootaki
authors.forename: Keiji
authors.initials: K
authors.lastname: Kamohara
authors.forename: Gordon B
authors.initials: GB
authors.lastname: Hirschman
authors.forename: Nicholas G
authors.initials: NG
authors.lastname: Vitale
authors.forename: Peter A
authors.initials: PA
authors.lastname: Chapman
authors.forename: William A
authors.initials: WA
authors.lastname: Smith
authors.forename: Kiyotaka
authors.initials: K
authors.lastname: Fukamachi
mesh_terms: D000818:Animals; D001794:Blood Pressure; D002417:Cattle; D006339:Heart Rate; D006354:Heart, Artificial; D013318:Stroke Volume