Calculating sympathovagal balance from heart rate variability: are there alternatives in adolescents?
OBJECTIVE
Assessing sympathovagal balance by calculating LF/HF-ratio from power spectral analysis (PSA) of heart rate variability (HRV) may be difficult in adolescents as chaotic breathing leads to methodical bias and metronomic breathing is not easy to perform. Diastolic blood pressure variability (dBPV) is less influenced and may therefore offer more stable values for calculations. The present study was performed on 72 paediatric subjects to investigate possible alternative LF/HF-calculations from PSA of HRV and dBPV.


RESULTS
Seventy-two paediatric individuals in three groups: 12 controls, 17 heart- and heart-lung-transplanted children (TX) and 43 adolescents born small for gestational age (SGA). Short-term beat-to-beat HRV and BP-recordings were made supine and during active standing. Ratios calculated: LF/HF from HRV, LF/HF from dBPV, LF-dBPV/HF-HRV and LF-HRV/HF-dBPV. LF/HF from dBPV as well as LF-HRV/HF-dBPV did not correlate with LF/HF-HRV. Correlation of LF/HF from HRV and LF-dBPV/HF-HRV was high especially in TX and in patients with resting heart rate of above 90 beats per minute.


CONCLUSIONS
In adolescents, the ratio of LF-dBPV/HF-HRV may be an alternative method for calculating sympathicovagal balance being less influenced by breathing patterns. In younger patients with elevated resting heart rate, but also in patients with very low HRV such as TX-patients this method could be a supplemental diagnostic tool whenever autonomic nervous control on the cardiocirculatory system has to be assessed.
Dalla Pozza
Robert
R
Department of Paediatric Cardiology, Ludwig-Maximilians University, Munich, Germany. Robert.DallaPozza@med.uni-muenchen.de
Kleinmann
Arne
A
Bechtold
Susanne
S
Kozlik-Feldmann
R
R
Daebritz
S
S
Netz
Heinrich
H
D000293:Adolescent; D001794:Blood Pressure / Q000502:physiology; D002648:Child; D004562:Electrocardiography; D005260:Female; D005583:Fourier Analysis; D006321:Heart / Q000294:innervation*; D006339:Heart Rate / Q000502:physiology*; D006801:Humans; D008297:Male; D012016:Reference Values; D012119:Respiration; D012815:Signal Processing, Computer-Assisted; D013564:Sympathetic Nervous System / Q000502:physiology*; D014630:Vagus Nerve / Q000502:physiology*