Dynamics of muscle sympathetic nerve activity in advanced heart
failure patients.
Nguyen, Alison H., Alan Garfinkel, Donald O. Walter, Michele A.
Hamilton, Gregg C. Fonarow, Jaime D. Moriguchi, Antoine Hage, James
N. Weiss, Holly R. Middlekauff.
Division of Cardiology, UCLA School of Medicine, Los Angeles,
California 90095; Ahmanson-UCLA Cardiomyopathy Center, UCLA Medical
Center, Los Angeles, California 90095; Department of Physiological
Science, UCLA, Los Angeles, California 90095
APStracts 3:0200H, 1996.
Muscle sympathetic nerve activity (MSNA) is increased in patients with
heart failure, compared to healthy subjects. We applied spectral and
correlation techniques to determine if qualitative as well as
quantitative differences in MSNA differentiate heart failure patients
from healthy subjects. We recorded MSNA, heart rate, and respiration
in 11 heart failure patients and 10 healthy humans. Our results are:
1) Statistically significant low frequency modulation of MSNA at
0.029+0.002 Hz (mean+SEM, range 0.026 to 0.038 Hz) was found in 10 of
11 heart failure patients, but in only 2 of 10 healthy controls
(differences between groups, _2 test, p < 0.01). 2) Heart rate
and respiration also demonstrated significant low frequency
modulation in a similar range. 3) Spectral and correlation techniques
revealed that low frequency modulation of MSNA was highly correlated
with low frequency modulation of respiration in heart failure
patients, but not in healthy subjects. In contrast, low frequency
modulation of MSNA did not correlate well with low frequency
modulation of heart rate. In summary, low frequency modulation of
respiration is coupled to low frequency modulation of MSNA in heart
failure patients, but not in normal subjects. We speculate that this
low frequency modulation of respiration may represent sub-clinical
Cheyne-Stokes breathing which has marked qualitative effects on MSNA
in patients with heart failure.
Received 31 August 1995; accepted in final form 3 April 1996.
APS Manuscript Number H824-5.
Article publication pending Am. J. Physiol. (Heart Circ. Physiology).
ISSN 1080-4757 Copyright 1996 The American Physiological Society.
Published in APStracts on 8 May 96