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Effect of HeartMate left ventricular assist device on cardiac autonomic nervous activity
S Y Kim1, A Montoya, J P Zbilut
1Department of Thoracic and Cardiovascular Surgery, Loyola University Medical Center, Maywood, Illinois 60153, USA.
Background:
Clinical performance of a left ventricular assist device is assessed via hemodynamic parameters and end-organ function. This study examined effect of a left ventricular assist device on human neurophysiology.
Methods:
This study evaluated the time course change of cardiac autonomic activity of 3 patients during support with a left ventricular assist device before cardiac transplantation. Cardiac autonomic activity was determined by power spectral analysis of short-term heart rate variability. The heart rate variability before cardiac transplantation was compared with that on the day before left ventricular assist device implantation.
Results:
The standard deviation of the mean of the R-R intervals of the electrocardiogram, an index of vagal activity, increased to 27 +/- 7 ms from 8 +/- 0.6 ms. The modulus of power spectral components increased. Low frequency (sympathetic activity) and high frequency power (vagal activity) increased by a mean of 9 and 22 times of each baseline value (low frequency power, 5.2 +/- 3.0 ms2; high frequency power, 2.1 +/- 0.7 ms2). The low over high frequency power ratio decreased substantially, indicating an improvement of cardiac sympatho-vagal balance.
Conclusions:
The study results suggest that left ventricular assist device support before cardiac transplantation may exert a favorable effect on cardiac autonomic control in patients with severe heart failure.