Aa. Jimenez et al., APPRAISAL OF THE STATE OF THE AUTONOMIC N ERVOUS-SYSTEM IN HYPERTROPHIC CARDIOMYOPATHY ANALYZING HEART-RATE-VARIABILITY, Revista espanola de cardiologia, 51(4), 1998, pp. 286-291
Introduction. The analysis of heart rate variability has been accepted
as a non-invasive method to evaluate the influence of the autonomic n
ervous system over the heart. Although heart rate variability has been
used during the last decade in several illnesses the studies in hyper
trophic cardiomyophathy are scarce. Objectives. We report the activity
of the autonomic nervous system in patients with hypertrophic cardiom
yophathy using the analysis of heart rate variability. Patients and me
thods. Heart rate variability was evaluate by the analyzing 24-h ambul
atory electrocardiograms (Bolter) in 20 patients with hypertrophic car
diomyopathy and in 15 controls. This method has been used to measure h
eart rate variability. Spectral analysis of the frequencies were calcu
lated using fast Fourier transformation. Spectral heart rate variabili
ty was computed as high (0.15 to 0.40 Hz) low (0.04 to 0.15 Hz) and to
tal (0.01 to 1.0 Hz). We compared the relation between low/high freque
ncy as an index of the sympathic/parasympathic balance. All data are e
xpressed as mean value +/- SD. The unpaired Student t-test was used. A
two tailed p valued < 0.05 was considered statistically significant.
Results. There were no differences in the mean heart rates among the p
atients with hypertrophic cardiomyophathy and normal subjects (mean +/
- SD: 71 +/- 9 versus 74 +/- 11 beats/minute; p = NS) while there was
a significant decline in total spectral (mean +/- SD: 7.14 +/- 1.1 ver
sus 7.57 +/- 0.6 In [ms(2)]; p = 0.02) and high (mean +/- SD: 5,22 +/-
0.8 versus 5.63 +/- 1.3 In [ms(2)]; p = 0.04) as well as in low spect
ral frequency of heart rate variability (mean +/- SD: 22 +/- 0.8 versu
s 5.63 +/- 1.3 In [ms(2)]; p = 0.04) in patients with hypertrophic car
diomyopathy. There were no differences in the low/high frequency compo
nent ratio in these patients (mean +/- SD: 1.1 +/- 0.1 versus 1.2 +/-
0.1 In [ms(2)]; p = NS). Conclusions. These facts suggest that the pat
ients with hypertrophic cardiomyopathy have an alteration in the auton
omic nervous system: sympathic (low spectral frequencies) and parasymp
athic activity thigh spectral frequencies), although this does not ref
lect an imbalance between sympathic: and parasympathic activities (rel
ation of low to high spectral frequencies).