title: New technique measures decreased transmural myocardial pressure in cardiomyoplasty.
abstract: BACKGROUND
  We introduce the use of a fluid-filled balloon, interposed between myocardium and latissimus dorsi (LD), as a new technique to measure transmural myocardial pressure in an acute goat model of dynamic cardiomyoplasty.
  
  
  METHODS
  A half-ellipsoidal balloon, composed of polychloryl vinyl layers, was sutured to the atrioventricular groove in 5 goats, thereby completely enveloping both ventricles. Left LD dynamic cardiomyoplasty was then performed, anchoring the LD to the felt sewing skirt of the balloon so that the LD completely covered the balloon. Left ventricular pressure and balloon pressure were measured with the stimulator in the 1:2 mode as balloon volume was varied.
  
  
  RESULTS
  Average transmural myocardial pressure, defined as left ventricular pressure minus balloon pressure, decreased from 34.4 mm Hg to 15.6 mm Hg during stimulator-on beats (p < 0.05).
  
  
  CONCLUSIONS
  These results support the conclusion that dynamic cardiomyoplasty unloads the left ventricle by decreasing wall stress. Furthermore, transmural myocardial pressure decreased more when balloon volume was increased, implying that the LD sarcomere length has an effect on wall stress. A balloon may therefore allow optimization of LD sarcomere length and thus assisted cardiac performance.
authors.affiliation: Division of Cardiac Surgery, Brigham and Women's Hospital, Harvard Medical School, Boston, Massachusetts, USA.
authors.forename: F Y
authors.initials: FY
authors.lastname: Chen
authors.forename: L
authors.initials: L
authors.lastname: Aklog
authors.forename: B J
authors.initials: BJ
authors.lastname: deGuzman
authors.forename: R G
authors.initials: RG
authors.lastname: Laurence
authors.forename: G S
authors.initials: GS
authors.lastname: Couper
authors.forename: R F
authors.initials: RF
authors.lastname: Appleyard
authors.forename: L H
authors.initials: LH
authors.lastname: Cohn
authors.forename: T A
authors.initials: TA
authors.lastname: McMahon
mesh_terms: D000818:Animals; D001011:Aorta / Q000502:physiology; D018421:Cardiomyoplasty / Q000379:methods*; D006041:Goats; D006321:Heart / Q000502:physiology*; D009206:Myocardium; D011312:Pressure; D013318:Stroke Volume; D017725:Ventricular Pressure