Heart Rate Variability and Head-up Tilt Testing in Patients With Syncope of Undetermined Etiology

Takase, Bonpei; Bjerregaard, Preben; Greenwalt, Terry; Kotar, Susan L.; Janosik, Denise L.

doi:10.1253/jcj.60.841

Cited by 10 publications

(3 citation statements)

References 18 publications

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“…Grubb et al [9] and Takase et al [21] showed that the pulsatility index in the middle cerebral artery increased during HUT or standing and noted an increase in cerebral vascular resistance in patients with syncope. On the other hand, Levine et al [15] argued that increased cerebral vasoconstriction during orthostatic stress is not by itself sufficient to cause syncope.…”

Section: Discussionmentioning

confidence: 99%

Reduction of Carotid Artery Blood Flow in Pediatric Patients with Syncope: Evaluation with Head-Up Tilt Test

Kojo¹,

Wada²,

Akiyoshi³

et al. 2001

Neuropediatrics

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We investigated the effect of postural changes on cerebral circulation by measuring carotid artery blood flow (CABF) in the supine position and during head-up tilt (HUT) test using a Doppler flow meter. Subjects included 10 patients with neurally mediated syncope, 10 patients with orthostatic intolerance, 8 with epilepsy, aged between 8 to 24 years (mean +/- SD, 13.9 +/- 4.1 years). The test caused pallor and dizziness in 16 patients (symptomatic), while no symptoms were recognized in the other 12 patients (asymptomatic). Significant reductions in the mean CABF (Fm), maximum CABF (Fs) and minimum CABF (Fd), components of the CABF waveform, were noticed during HUT compared to before HUT (supine), and these reductions in symptomatic patients were more severe than those in asymptomatic patients (Fm: - 2.8 +/- 2.0 SD vs - 0.7 +/- 1.4 SD; Fs: - 2.7 +/- 1.5 SD vs - 0.9 +/- 1.3 SD; Fd: - 4.5 +/- 2.8 SD vs - 2.2 +/- 2.1 SD). Reductions in Fm, Fs and Fd in the symptomatic patients during HUT lasted longer than those of the asymptomatic patients, being statistically significant for Fm and Fs (Fm: p < 0.01; Fs: p < 0.05). The criteria during HUT for distinguishing neurally mediated syncope (NMS) from others was Fs: < - 4 SD and Fd: < - 5 SD. Our data suggest that reduction of CABF should be carefully evaluated for the diagnosis of neurally mediated syncope in pediatric patients. Such a reduction might be an essential mechanism of syncopal attacks.

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Section: Discussionmentioning

confidence: 99%

Reduction of Carotid Artery Blood Flow in Pediatric Patients with Syncope: Evaluation with Head-Up Tilt Test

Kojo¹,

Wada²,

Akiyoshi³

et al. 2001

Neuropediatrics

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“…We used a passive head-up tilt test to stimulate adaptation reactions in cardiovascular autonomic control and evaluate it (Montano et al 1994, Takase et al 1996, Suzuki et al 2006. The electrocardiogram (ECG), PPGs from the middle finger of the right and left hand (denoted below as PPG(R) and PPG(L), respectively), PPG from the earlobe (denoted below as PPG(ear)), and respiration were simultaneously recorded during 10 min in healthy subjects at each stage of the head-up tilt test.…”

Section: Signal Recordingmentioning

confidence: 99%

A comprehensive assessment of cardiovascular autonomic control using photoplethysmograms recorded from the earlobe and fingers

et al. 2016

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We compare the spectral indices of photoplethysmogram variability (PPGV) estimated using photoplethysmograms recorded from the earlobe and the middle fingers of the right and left hand and analyze their correlation with similar indices of heart rate variability (HRV) in 30 healthy subjects (26 men) aged 27 (25, 29) years (median with inter-quartile ranges) at rest and under the head-up tilt test. The following spectral indices of PPGV and HRV were compared: mean heart rate (HR), total spectral power (TP), high-frequency (HF) and low-frequency (LF) ranges of TP in percents (HF% and LF%), LF/HF ratio, and spectral coherence. We assess also the index S of synchronization between the LF oscillations in HRV and PPGV. The constancy of blood pressure (BP) and moderate increase of HR under the tilt test indicate the presence of fast processes of cardiovascular adaptation with the increase of the sympathetic activity in studied healthy subjects. The impact of respiration on the PPGV spectrum (accessed by HF%) is less than on the HRV spectrum. It is shown that the proportion of sympathetic vascular activity (accessed by LF%) is constant in the PPGV of three analyzed PPGs during the tilt test. The PPGV for the ear PPG was less vulnerable to breathing influence accessed by HF% (independently from body position) than for PPGs from fingers. We reveal the increase of index S under the tilt test indicating the activation of interaction between the heart and distal vessels. The PPGV spectra for finger PPGs from different hands are highly coherent, but differ substantially from the PPGV spectrum for the ear PPG. We conclude that joint analysis of frequency components of PPGV (for the earlobe and finger PPGs of both hands) and HRV and assessment of their synchronization provide additional information about cardiovascular autonomic control.

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“…Even if the model is limited to autonomic control of circulation, the simplification is necessary, which leads to a limited description of a specific pathology or effect. For example, a passive head-up tilt test [22][23][24][25] is one of the most common tests to investigate autonomic control adaptation both in medical practice and fundamental studies. There are a number of cardiovascular models [26][27][28][29] capable of precise simulation of arterial pressure (AP) and heart rate dynamics during a passive tilt test.…”

mentioning

confidence: 99%

Mathematical modeling of the cardiovascular autonomic control in healthy subjects during a passive head-up tilt test

Ishbulatov

Karavaev

Kiselev

et al. 2020

Sci Rep

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A mathematical model is proposed for the autonomic control of cardiovascular system, which takes into account two separated self-exciting sympathetic control loops of heart rate and peripheral vascular tone. The control loops are represented by self-exciting time-delay systems and their tone depends on activity of the aortic, carotid, and lower-body baroreceptors. The model is used to study the dynamics of the adaptive processes that manifest in a healthy cardiovascular system during the passive head-up tilt test. Computer simulation provides continuous observation of the dynamics of the indexes and variables that cannot be measured in the direct experiment, including the noradrenaline concentration in vessel wall and heart muscle, tone of the sympathetic and parasympathetic control, peripheral vascular resistance, and blood pressure. In the supine and upright positions, we estimated the spectral characteristics of the model variables, especially in the low-frequency band, and the original index of total percent of phase synchronization between the low-frequency oscillations in heart rate and blood pressure signals. The model demonstrates good quantitative agreement with the dynamics of the experimentally observed indexes of cardiovascular system that were averaged for 50 healthy subjects.

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Heart Rate Variability and Head-up Tilt Testing in Patients With Syncope of Undetermined Etiology

Cited by 10 publications

References 18 publications

Reduction of Carotid Artery Blood Flow in Pediatric Patients with Syncope: Evaluation with Head-Up Tilt Test

Reduction of Carotid Artery Blood Flow in Pediatric Patients with Syncope: Evaluation with Head-Up Tilt Test

A comprehensive assessment of cardiovascular autonomic control using photoplethysmograms recorded from the earlobe and fingers

Mathematical modeling of the cardiovascular autonomic control in healthy subjects during a passive head-up tilt test

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