[The hemodynamic and myostimulation regimens parallels of the extraaortic counterpulsation and skeletal ventricle in the experiment].

Objective: Our investigation was aimed to evaluate the effect of extraaortic counterpulsation to central hemodynamics during the two modes of latissimus dorsi muscle electrostimulation.

Material And Methods: Two groups of experimental dogs were divided into two subgroups and affected with continuous and work-rest regimens of stimulation. In one group latissimus dorsi muscle was mobilized and left in situ. The contraction force was measured before and during experiment, until it decreased till 50%. Recovery time needed to completely restore contraction force was calculated. In the second group latissimus dorsi muscle was stimulated just after aortomyoplasty and skeletal muscle ventricle by using LD PACE II electrostimulator (ventricle - muscle delay 290 ms).

Results: By using continuous stimulation in the first group the contraction force decreased till 50% of pre-assist level after 52+/-8 minutes and returned to baseline after 84+/-16 minutes of rest. Under the work-rest regimen this decrease lasted 105+/-8 minutes and returned to baseline after 25+/-6 minutes (p<0.05). After this regimen light microscopy did not revealed significant changes of muscle tissue. After continuous stimulation increased basophilic degeneration and wavy fibrils were revealed. Thoracic aortic counterpulsation by using continuous stimulation increased hemodynamic parameters from pre-assisted level in 40 minutes. The hemodynamic parameters during work-rest regimen became better after 20 minutes and lasted 100 minutes (p<0.05). When counterpulsation was completed, recovery time to baseline in case of continuous electrostimulation was 96+/-9 minutes; in case of work-rest electrostimulation, it was only 43+/-6 minutes.

Conclusions: Work-rest regimen using LD PACE II electrostimulator may be used safely immediately post cardiac assist procedure.