TY - JOUR
TI - Heart rate variability is augmented in patients with positional
obstructive sleep apnea, but only supine LF/HF index correlates with its
severity
AU - Flevari, Aikaterini
AU - Vagiakis, Emmanouil
AU - Zakynthinos, Spyridon
JO - Sleep and Breathing
PY - 2015
VL - 19
TODO - 1
SP - 359-367
PB - Springer Berlin Heidelberg
SN - 1520-9512, 1522-1709
TODO - 10.1007/s11325-014-1029-2
TODO - Heart rate variability; Positional obstructive sleep apnea; Body
posture; Time and frequency domain analysis; Arousals
TODO - Data on cardiac autonomic functioning, as expressed by heart rate
variability (HRV), in patients with positional obstructive sleep apnea
(p-OSA) disorder are lacking. The purpose of the study was to compare
HRV indices between sleep segments derived from supine body position and
another body position with and without apneic events, respectively. Our
intention was to find some correlation between HRV indices and the
pathophysiological characteristics of the corresponding temporal period.
Nocturnal polysomnograms derived from twenty-seven patients (22 men)
with documented positional apnea were retrospectively reviewed. Patients
never treated for OSA and free from diseases/drugs altering HRV were
examined. Data from total sleep studies were collected. Two N2 sleep
segments, from supine body position with sleep-disordered breathing
(SDB) and another body position without SDB were analyzed. Apneic events
(namely, apneas, hypopneas, and respiratory effort-related arousals
(RERAs)), arousals, number of desaturations, minimum pulse oximetry
(SaO(2)min), time domain variables (average RR, SDNN, SDSD, RMSSD,
pNN50, and HRV triangular index) and frequency domain variables (VLF,
LF, HF, TP, LF/HF) were recorded for both temporal periods.
With the exception of average RR and HF, all other variables were
significantly higher in segments with SDB. Only LF/HF_supine ratio was
positively correlated with the apneic_supine_index (t = 3.13, p <
0.01) and negatively correlated with SaO(2)min (t = -2.9, p < 0.01) and
the desaturation_supine_index (t = -2.5, p = 0.02). Arousals were
negatively correlated with SaO(2)min (t = -2.8, p < 0.01).
SDB augments autonomic tone in patients with p-OSA, but only LF/HF
correlates with its severity and might be used as a screening tool in
the future. On the contrary, parasympathetic tone, as reflected by HF,
remains constant in both periods.
ER -