title: Chronic counterpulsation with descending thoracic aortomyoplasty improved cardiac function in animals with heart failure.
abstract: Descending thoracic aortomyoplasty uses latissimus dorsi muscle for extraaortic diastolic counterpulsation. We hypothesized that descending thoracic aortomyoplasty could improve ventricular function in dogs (n = 5) with heart failure. The left latissimus dorsi muscle was wrapped around the descending aorta and conditioned for 4 weeks with a burst stimulator (five pulses, 33 Hz, 28 bursts/min). Heart failure was induced by rapid ventricular pacing after conditioning. Left ventricular volume was measured with a conductance catheter. Left ventricular and aortic pressures were measured with a micromanometer. Mean diastolic blood pressure, endocardial viability ratio, left ventricular peak pressure, left ventricular end-diastolic pressure, stroke work, isovolumic relaxation time constant, and the end-systolic pressure volume relation were measured at baseline (after heart failure) and with the descending thoracic aortomyoplasty stimulated at 1:1. Contraction of the descending thoracic aortomyoplasty augmented mean diastolic blood pressure (62 +/- 4 to 71 +/- 3 mm Hg) and endocardial viability ratio (1.0 +/- 0.30 to 1.5 +/- 0.13) (p < 0.05). Left ventricular peak pressure (98 +/- 4 to 88 +/- 3 mm Hg), left ventricular end-diastolic pressure (19 +/- 4 to 14 +/- 4 mm Hg), and stroke work (1048 +/- 124 to 743 +/- 80 mm Hg.cm3) (p < 0.05) were reduced. The end-systolic pressure volume relation increased with descending thoracic aortomyoplasty stimulation (3.7 +/- 0.7 to 4.5 +/- 0.8 mm Hg/mL), and the isovolumic diastolic relaxation time constant significantly decreased (54 +/- 6 to 49 +/- 7 msec) (p < 0.05). We conclude that descending thoracic aortomyoplasty can provide diastolic counterpulsation and reduce stroke work in animals with heart failure.(ABSTRACT TRUNCATED AT 250 WORDS)
authors.affiliation: Department of Surgery, Allegheny General Hospital, Pittsburgh, PA 15212.
authors.forename: R R
authors.initials: RR
authors.lastname: Lazzara
authors.forename: D R
authors.initials: DR
authors.lastname: Trumble
authors.forename: J A
authors.initials: JA
authors.lastname: Magovern
mesh_terms: D000818:Animals; D001013:Aorta, Thoracic / Q000502:physiology*; D018421:Cardiomyoplasty / Q000379:methods*; D015908:Counterpulsation / Q000379:methods*; D004285:Dogs; D006333:Heart Failure / Q000503:physiopathology / Q000601:surgery*; D006439:Hemodynamics / Q000502:physiology*; D016277:Ventricular Function, Left / Q000502:physiology*