• R R Lazzara, D R Trumble, and J A Magovern.
• Department of Surgery, Allegheny General Hospital, Pittsburgh, PA 15212.
• J. Heart Lung Transplant. 1994 Jul 1; 13 (4): 652-60.

AbstractDescending 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)

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