Circulation, Vol 84, 2470-2475, Copyright © 1991 by American Heart Association
H Niinami, TL Hooper, RL Hammond, R Ruggiero, A Pochettino, M Colson and LW Stephenson
BACKGROUND. Previous attempts to provide right heart assistance with
skeletal muscle ventricles (SMVs) have been frustrated by the low preload
supplied by the systemic venous blood pressure. In the present study, right
ventricular pressure was exploited to provide more optimal preload, the SMV
being connected by valved conduits between right ventricular free wall and
the main pulmonary artery. METHODS AND RESULTS. SMVs were constructed from
the right latissimus dorsi muscle in seven mongrel dogs. Following a delay
period of 4 weeks, SMVs were preconditioned with 2-Hz continuous
stimulation for 5-6 weeks. The SMV was then connected to the right
ventricle using a porcine valved Dacron conduit. A similar valved conduit
connected the SMV to the main pulmonary artery that had been ligated
proximally. SMVs were stimulated with 33-Hz burst frequency to contract
synchronously with ventricular diastole in a 1:2 mode. The stimulator was
intermittently turned off to permit comparison of assisted and nonassisted
circulation. Cardiac output increased by 27% at 1 hour (1,437 +/- 54 versus
1,140 +/- 64 ml/min, p less than 0.005) and by 30% at 4 hours (1,403 +/-
161 versus 1,074 +/- 99 ml/min, p less than 0.005), systemic arterial
systolic pressure increased at 1 hour by 12% (87.1 +/- 4.9 versus 78.0 +/-
4.9 mm Hg, p less than 0.05) and by 13% at 4 hours (81.4 +/- 2.8 versus
72.3 +/- 3.4 mm Hg, p less than 0.005), and peak pulmonary arterial
pressure increased at 1 hour by 35% (28.0 +/- 2.1 versus 20.9 +/- 1.8 mm
Hg, p less than 0.01) and by 37% at 4 hours (31.5 +/- 2.6 versus 23.0 +/-
0.4 mm Hg, p less than 0.05). Peak SMV pressure was 52.8 +/- 2.0 mm Hg at 1
hour and 49.9 +/- 3.3 mm Hg at 4 hours (p = NS). CONCLUSIONS. The improved
preload supplied by this configuration of right ventricular assist enabled
an SMV to provide stable and effective circulatory support throughout the
4-hour duration of the experiment.
ARTICLES
A new configuration for right ventricular assist with skeletal muscle ventricle. Short-term studies
Department of Surgery, Wayne State University, School of Medicine, Detroit, Mich.
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