SPECTRAL-ANALYSIS OF HEMODYNAMICS DURING LEFT-VENTRICULAR ASSISTANCE

In order to analyze the autonomic nervous system during left ventricul ar (LV) assistance, fluctuations in hemodynamic derivatives were evalu ated by a spectral analyzing method using a fast fourier transform (FF T) methodology. After the left pleural cavity was opened through the f ourth intercostal space under general anesthesia, a pneumatically driv en ventricular assist system was implanted as in left heart bypasses i n chronic animal experiments, using three healthy adult goats. Hemodyn amic parameters with and without LV assistance were recorded on a magn etic tape in the awake condition then analyzed in a computer system th rough an A-D convertor Power spectral analysis was performed on a beat -to-beat basis for the evaluation of the fluctuations. During copulsat ion mode LV assistance, Mayer wave fluctuations (0.1 Hz) were signific antly increased compared with counterpulsation mode LV assist, suggest ing an increase in sympathetic tone. Go-pulsation mode LV assist is re ported to increase the afterload of the natural left ventricle, thus, the sympathetic tone may be increased to maintain a natural heart outp ut.