Increased sympathetic and decreased parasympathetic cardiac innervation in patients with Alzheimer's disease
J. Aharon-Peretz, T. Harel, M. Revach and S. A. Ben-Haim
Department of Neurology, Rambam Medical Center, Haifa, Israel.
To assess whether Alzheimer's disease affects the sympathetic and
parasympathetic influences on the heart rate, we used power spectrum
analysis of heart rate variability derived from simple body-surface
electrocardiography. We calculated the energy ratio of low- to
high-frequency bands. This ratio was significantly higher in patients with
Alzheimer's disease than in normal controls (upright posture, 0.41 +/- 0.21
vs 0.23 +/- 0.08). The parasympathetically mediated baroreceptor activity
reflected by the energy ratio of medium- to low- and high-frequency bands
was significantly depressed in patients with Alzheimer's disease (upright
posture, 0.12 +/- 0.02 vs 0.07 +/- 0.03; supine posture, 0.11 +/- 0.02 vs
0.085 +/- 0.025). Compared with normal volunteer controls, patients with
Alzheimer's disease manifested a relatively hypersympathetic,
hypoparasympathetic state.
