Cardiovascular variability after arousal from sleep: time-varying spectral analysis

Abstract

We performed time-varying spectral analyses of heart rate variability (HRV) and blood pressure variability (BPV) recorded from 16 normal humans during acoustically induced arousals from sleep. Time-varying autoregressive modeling was employed to estimate the time courses of high-frequency HRV power, low-frequency HRV power, the ratio between low-frequency and high-frequency HRV power, and low-frequency power of systolic BPV. To delineate the influence of respiration on HRV, we also computed respiratory airflow high-frequency power, the modified ratio of low-frequency to high-frequency HRV power, and the average transfer gain between respiration and heart rate. During cortical arousal, muscle sympathetic nerve activity and heart rate increased and returned rapidly to baseline, but systolic blood pressure, the ratio between low-frequency and high-frequency HRV power, low-frequency HRV power, the modified ratio of low-frequency to high-frequency HRV power, and low-frequency power of systolic BPV displayed increases that remained above baseline up to 40 s after arousal. High-frequency HRV power and airflow high-frequency power showed concommitant decreases to levels below baseline, whereas the average transfer gain between respiration and heart rate remained unchanged. These findings suggest that 1) arousal-induced changes in parasympathetic activity are strongly coupled to respiratory pattern and 2) the sympathoexcitatory cardiovascular effects of arousal are relatively long lasting and may accumulate if repetitive arousals occur in close succession.

On arousal from sleep: time-frequency analysis

“…Our results are in agreement with the previous studies [8,9,33]. On the other hand, there are little discrepancies with the study by Blasi et al [6], where the time evolution of the spectral parameters is analyzed. LF time activation and the time frame, in which, spectral indexes remain altered after arousal event, are much longer in [6] than in the present study.…”

“…Only few works applied more sophisticated techniques such as time-varying analysis, to evaluate the dynamic changes of the cardiovascular control during arousals [6]. To this regard, we focused our attention on a special and well-known set of tools called Cohen's class time-frequency distributions (TFDs) [16].…”

Abnormal autonomic cardiac response to transient hypoxia in sickle cell anemia

“…This method is based on a recursive autoregressive algorithm used by our group in previous studies on obstructive sleep apnea patients (Blasi et al 2003a(Blasi et al , 2003b.…”

Fenómenos fisiopatológicos sistémicos asociados al bruxismo de sueño

“…También se ha informado que PAS sigue siendo significativamente superior al valor inicial durante 40 segundos después de una excitación cortical (32). Por lo tanto es posible que la activación simpática con excitación durante el sueño y AMMR/BS pueda afectar variablemente las respuestas cardíaca y vascular, con una rápida normalización de la resistencia vascular periférica tal como se refleja por una rápida normalización de la PAD, y un efecto más sostenido sobre la contractilidad cardíaca conduce a la normalización retardada de la PAS.…”