Spectral Analysis Of Heart Rate Research Articles

Parasympathetic nervous activity after administration of atropine and neostigmine using heart rate spectral analysis.

Recently, heart rate spectral analysis has become recognized as a powerful tool for quantitatively evaluating autonomic nervous system activity. The purpose of this study was to analyze parasympathetic nervous activity by heart rate spectral analysis after administration of atropine and neostigmine for reversal of residual neuromuscular blockade. For our study, 36 female patients (26-37 years of age), ASA physical status (PS) I, who were scheduled for laparoscopic examination, were randomly allocated to one of the following four groups: In group A (1∶1), 9 patients received 1.0mg atropine followed 4 min later by 1.0 mg neostigmine. In group B (1∶2), 9 patients received 0.5 mg atropine followed 4 min later by 1.0 mg neostigmine. In group C (1∶2.5), 9 patients received 1.0 mg atropine followed 4 min later by 2.5 mg neostigmine. In group D (1∶2 mix), 9 patients received a mixed solution of atropine 0.5 mg and neostigmine 1.0mg. After finishing the laparoscopic examination, additional anesthesia was maintained with 70% nitrous oxide, 30% oxygen, and 0.5% isoflurane. The control data were obtained 10 min after finishing the laparoscopic examination. After that, the data on atropine were obtained between 2 and 4min after administration of atropine, and the data on neostigmine were obtained between 5 and 7 min after administration of neostigmine. We selected power spectral density of the high-frequency component (HF-p) in heart rate spectral analysis as an index to assess parasympathetic activity. In groups A, B, and C, the HF-p decreased after administration of atropine. In groups B and C, the HF-p increased after administration of neostigmine as compared to the control. In group A, the HF-p increased after neostigmine but did not differ from the control. The difference between groups D and B was not statistically significant. From the results of this study, we concluded that the muscarinic effect of neostigmine could not be sufficiently blocked by atropine at 1/2 dosages of neostigmine, but could be sufficiently blocked by atropine at equivalent dosages of neostigmine, under light isoflurane anesthesia.

Hemodynamic Effects and Power Spectral Analysis of Heart Rate and Arterial Pressure Variabilities Induced by Lercanidipine and Its Enantiomers in Conscious Dogs

This study was performed to investigate the hemodynamic properties and to analyze the effects on spectral analysis indexes (LFRR, HFRR) of autonomic control of cardiovascular function induced by administration of lercanidipine and its enantiomers in conscious, instrumented dogs. After cumulative i.v. administration, lercanidipine and its (S)-enantiomer induced dose-dependent peripheral and coronary vasodilatation. Concomitant increases in dP/dtmax and cardiac output were observed. (S)-Lercanidipine modified hemodynamic parameters, paralleling the action of the racemate at half-dose. (R)-Lercanidipine was devoid of any vasodilating action. The effects of nitrendipine on peripheral and coronary vasculature were similar to those of lercanidipine but with a lesser increase of dP/dtmax compared to lercanidipine. Both (S)-lercanidipine and lercanidipine caused a significant increase in heart rate, but only (S)-lercanidipine significantly increased LFRR. The marker of vasomotor activity LFSAP showed a mild reduction after lercanidipine, suggesting the possibility of a blunting action on vasomotor sympathetic activity. After lercanidipine infusion at a dose of 1 μg/kg/min for 15 min, total peripheral resistance and coronary resistance decreased significantly, together with a corresponding increase in coronary blood flow. After β-adrenergic blockade with propranolol, its coronary effects were slightly reduced. The time relaxation constant TAU was not modified in both conditions. Continuous infusion of lercanidipine did not modify the spectral markers LFRR and LFSAP. Pretreatment with propranolol did not significantly alter the response to lercanidipine, thus confirming the virtual absence of sympathetic activation during continuous infusion. In conclusion, lercanidipine is confirmed to be a direct and potent vasodilator calciumentry blocker with selectivity for the vascular bed.

Spectral Analysis of Heart Rate and Blood Pressure Variability during Hemorrhage in Thiopental-anesthetized Rats

Spectral Analysis of Heart Rate and Blood Pressure Variability during Hemorrhage in Thiopental-anesthetized Rats

Study of cardiovascular vagosympathetic control by spectral analysis of heart rate and blood pressure in obese patients

Study of cardiovascular vagosympathetic control by spectral analysis of heart rate and blood pressure in obese patients

Dopamine and Sympathoadrenal Activity in Man

The sympathetic adrenal (SA) activity can be modulated by dopamine (DA) through D2 receptors. In man, using D2 antagonists, it has been demonstrated that endogenous DA plays an inhibitory modulation of the SA system during high degree of SA activation. D2 agonists are able to induce a decrease in norepinephrine (NE) release either in vitro or in vivo. This effect leads, in vivo, to a decrease in blood pressure (BP) and to an activation of arterial baroreceptors. Therefore, in vivo, the D2 mediated inhibition of epinephrine (E) release, which is clearly demonstrated in vitro, is overwhelmed by the baroreceptor-mediated activation of the splachnic nerve. As a consequence, the in vivo administration of D2 agonists can induce a different effect on the net peripheral sympathetic tone of an organ, depending on the balance between the degree of the baroreceptor-mediated sympathetic activation and the inhibitory D2-mediated inhibition of NE release at the tissue level. In the present paper we investigated the in vivo effect of placebo (PL) or acute oral bromocriptine (BC) administration on plasma CA and on the cardiac sympatho-vagal balance of 7 normal volunteers, as assessed by power spectral analysis of heart rate (HR) variability (autoregressive method), either in resting or sitting position. Low frequency (LF) and high frequency (HF) components, both expressed in normalized units (nU), and LF/HF ratio were calculated. BC caused a decrease in BP, plasma NE and no change in HR in resting and sitting position. Plasma E increased in sitting position. At the heart level, after BC, we observed, during rest, an increase in LF and LF/HF ratio and a decrease in HF while in sitting position LF did not increase krther. These data show that BC, while reducing BP through a decrease of plasma NE, increases LF/HF ratio (sympathetic tone) without any change in heart rate. These data seem to confirm that BC causes an inhibitory modulation of the SA system acting predominantly at the periphery through D2 presynaptic receptors.

EFFECTS OF EXCITATIVE AND SEDATIVE MUSIC ON SUBJECTIVE AND PHYSIOLOGICAL RELAXATION

Previous investigations using heart rate as a measure have not clarified the excitative-sedative effects of music. One of the sources of this failure was considered to be use of the index of heart rate. The present purpose was to examine the excitative-sedative effect of music on indices of the sympathetic and the parasympathetic nervous activities through spectral analysis of heart rate. The presented stimuli were three excitative musical pieces and three sedative ones. Subjective feelings about music were measured by an adjective checklist concerning musical activity. Heart-rate variabilities divided into two components of Low Frequency, mainly affected by the sympathetic nervous system and of High Frequency, mainly affected by the parasympathetic nervous system. Six types of heart-rate indices were employed: (1) mean increments from posttrial base, (2) coefficient of variances of heart rate, (3) mean powers of Low Frequency, (4) coefficient of component variances of Low Frequency, (5) mean powers of High Frequency, and (6) coefficient of component variances of High Frequency. From the factor analysis based on responses to an adjective checklist, there was a single major activity factor. Activity scores showed some were high during excitative pieces and others low during sedative ones. For heart rate, excitative-sedative effects of music were observed only in indices related to High Frequency. This result suggests that musical effect was observed in measures of the parasympathetic nervous system but not in the sympathetic nervous system.

Parasympathetic nervous activity after administration of atropine and neostigmine using heart rate spectral analysis

Parasympathetic nervous activity after administration of atropine and neostigmine using heart rate spectral analysis

Assessment of autonomic nervous function by power spectral analysis of heart rate variability in the horse

We studied power spectral analysis of heart rate (HR) variability in the horse, with the hypothesis that the quantitative information provided by the spectral analysis of HR variability reflects the interaction between sympathetic and parasympathetic regulatory activities. For this purpose, electrocardiogram, blood pressure (BP) and respiratory (Resp) waveform were simultaneously recorded from Thoroughbred horses (3–5 years old) and analyzed by power spectrum. There were two major spectral components at low-frequency (LF) and high-frequency (HF) bands for HR variability. The peak of Resp variability clearly occurred at the HF range. In contrast to Resp variability, the power spectra of BP variability occurred at lower frequencies. The maximum coherence between HR and Resp variabilities and HR and BP variabilities occurred at ∼ 0.15 and ∼ 0.03 Hz, respectively. These relationships were similar to the ensemble spectra. On the basis of these data, we have defined two frequency bands of interest: LF (0.01–0.07 Hz) and HF (0.07–0.6 Hz). Therefore, we believe that power spectral analysis of HR variability provides a very powerful technique for assessing autonomic nervous activity in the horse.

Power spectral analysis of heart rate in hyperthyroidism

Power spectral analysis of heart rate in hyperthyroidism

Power spectral analysis of heart rate in hyperthyroidism.

The aim of the present study was to evaluate the impact of hyperthyroidism on the cardiovascular system by separately analyzing the sympathetic and parasympathetic influences on heart rate. Heart rate variability was evaluated by autoregressive power spectral analysis. This method allows a reliable quantification of the low frequency (LF) and high frequency (HF) components of the heart rate power spectral density; these are considered to be under mainly sympathetic and pure parasympathetic control, respectively. In 10 newly diagnosed untreated hyperthyroid patients with Graves' disease, we analyzed power spectral density of heart rate cyclic variations at rest, while lying, and while standing. In addition, heart rate variations during deep breathing, lying and standing, and Valsalva's maneuver were analyzed. The results were compared to those obtained from 10 age-, sex-, and body mass index-matched control subjects. In 8 hyperthyroid patients, the same evaluation was repeated after the induction of stable euthyroidism by methimazole. Heart rate power spectral analysis showed a sharp reduction of HF components in hyperthyroid subjects compared to controls [lying, 13.3 +/- 4.1 vs. 32.0 +/- 5.6 normalized units (NU; P < 0.01); standing, 6.0 +/- 2.7 vs. 15.0 +/- 4.0 NU (P < 0.01); mean +/- SEM]. On the other hand components were comparable in the 2 groups (lying, 64.0 +/- 6.9 vs. 62.0 +/- 6.5 NU; standing, 77.0 +/- 6.5 vs. 78.0 +/- 5.4 NU). Hence, the LF/HF ratio, which is considered an index of sympathovagal balance, was increased in hyperthyroid subjects while both lying (11.3 +/- 4.5 vs. 3.5 +/- 1.1; P < 0.05) and standing (54.0 +/- 12.6 vs. 9.8 +/- 2.6; P < 0.02). This parameter was positively correlated with both T3 (r = 0.61; P < 0.05) and free T4 (r = 0.63; P < 0.05) serum levels. Among traditional cardiovascular autonomic tests, the reflex response of heart rate during lying to standing was significantly lower in hyperthyroid patients than in controls (1.12 +/- 0.03 vs. 1.31 +/- 0.04; P < 0.002). No statistically significant difference in reflex responses between the two groups was found in deep breathing or Valsalva's maneuver. In the 8 patients reexamined after methimazole treatment, we observed complete normalization of altered cardiovascular parameters, with slight predominance of the vagal component compared with controls. These results suggest that thyroid hormone excess may determine reduced parasympathetic activity and, thus, a relative hypersympathetic tone.

Acute Effect of Insulin on Autonomic Regulation of the Cardiovascular System: A Study by Heart Rate Spectral Analysis

Acute Effect of Insulin on Autonomic Regulation of the Cardiovascular System: A Study by Heart Rate Spectral Analysis

Acute Effect of Insulin on Autonomic Regulation of the Cardiovascular System: A Study by Heart Rate Spectral Analysis

Acute Effect of Insulin on Autonomic Regulation of the Cardiovascular System: A Study by Heart Rate Spectral Analysis

Age dependency of beat-to-beat fluctuations in hemodynamic variables: Spectral analysis of heart rate, blood pressure and acoustic quantification LV-area signals: Victor Mor-Avi PhD, Solange Akselrod PhD, Yael Amitay BS, Allan Jorge BS, Claudia Korcarz DVM, Joanne Sandelski RDMS, Jakob Karin PhD, Roberto Lang MD, Tel Aviv University, Israel and University of Chicago, Chicago IL

Age dependency of beat-to-beat fluctuations in hemodynamic variables: Spectral analysis of heart rate, blood pressure and acoustic quantification LV-area signals: Victor Mor-Avi PhD, Solange Akselrod PhD, Yael Amitay BS, Allan Jorge BS, Claudia Korcarz DVM, Joanne Sandelski RDMS, Jakob Karin PhD, Roberto Lang MD, Tel Aviv University, Israel and University of Chicago, Chicago IL

Deriving respiration from pulse wave: a new signal-processing technique

Investigations of autonomic nervous system activity using spectral analysis of heart rate (HR) and blood pressure (BP) variability is very popular in many scientific disciplines, and yet only half of all studies involving spectral analysis control for respiration. Because respiration modulates HR and BP variability, knowledge of the respiratory rate is necessary for the proper interpretation of HR and BP power spectra. We devised and validated a new signal-processing technique to derive respiration from the blood pressure wave. This technique is based on the relationship between oscillations in the area under the dicrotic notch of the pulse wave and respiration. The results of our view signal-processing technique yielded significant correlations between protocols of the actual number of respiratory cycles and our blood pressure-derived respiratory cycles and their respective spectra for a number of standard autonomic tests (P < 0.05). Our method will allow retrospective extraction of the respiratory wave and as such afford a more precise interpretation of HR and BP spectra.

Frequency domain of heart-rate and blood pressure variability in the essential hypertensive patients during sleep: differences between dippers and non-dippers.

METHODS: Autonomic nervous function was evaluated by means of power spectral analysis of heart rate and blood pressure variability in dipper (n = 10) and non-dipper (n = 9) essential hypertensive subjects during sleep. The non-dipper subjects were defined as those in whom the nocturnal decrease in blood pressure was < 10% of the daytime blood pressure. We measured beat-to-beat blood pressure by using a Finapres device and all stages of sleep by simultaneous polysomnographic recording during spontaneous nocturnal sleep. We analysed the pattern of changes in blood pressure for random periods of 4 min duration while the patient was awake and during all stages of sleep. For each period (waking, stages 2, 3 and 4 of sleep) a segment of 256 stationary data points was analysed. In the frequency domain, the spectral characteristics of the stationary segments were estimatred by fast Fourier transformation over three frequency bands: low frequency (0.025-0.07 Hz), mid-frequency (0.07-0.14 Hz) and high frequency (0.14-0.35 Hz). RESULTS: Pulse-interval power spectral analysis did not reveal any difference between dippers and non-dippers during waking. In dipper patients, the low-frequency pulse interval (LFPI) decreased during sleep whereas the high-frequency pulse interval increased; the mid-frequency systolic blood pressure and diastolic blood pressure (DBP) decreased significantly and the high-frequency DBP increased during sleep. In non-dipper patients, the LFPI increased from wakefulness to stages 2 and 3 of sleep and the high-frequency pulse interval decreased during sleep; the mid-frequency systolic blood pressure and DBP increased in stage 4 sleep and the high-frequency DBP decreased during sleep. CONCLUSIONS: These findings indicate that non-dipper hypertensive subjects are characterized by increased LFPI and mid-frequency blood pressure during sleep compared with dipper subjects. This alteration in the autonomic nervous function may explain the non-dipper phenomenon in essential hypertension.

Power spectral analysis of heart-rate variability reflects the level of cardiac autonomic activity in rabbits

Power spectral analysis of heart rate (HR[ variability was tested in conscious rabbits to assess the reliability of this method for assessing cardiac autonomic function in normal rabbits under resting conditions. Evaluation of power spectrum was performed in 5 rabbits under normal resting conditions and after sympathetic, parasympathetic and combined sympathetic plus parasympathetic blockade. Rabbits were randomly assigned to undergo sympathetic (propranolol[ or parasympathetic (methscopolamine[ blockade at the initial step followed by combined blockade. The power spectrum of heart-rate variability in rabbits was presented as one broad spectral component at frequencies mainly between 0 and 0.5 Hz. This component was considerably modulated by both sympathetic and parasympathetic influences with substantial overlap of sympathetic- and parasympathetic-related components of the spectrogram. Nevertheless, it was clearly shown that power of heart-rate variability at frequencies from 0.4373 Hz to 0.5625 Hz was determined only by parasympathetic influences, and sympathetic modulation of HR was presented mainly at frequencies from 0.0625 Hz to 0.1875 Hz. Spectral subcomponent analysis of the power spectrum of HR variability may be useful to follow changes in cardiac autonomic function in rabbits.

Power spectral analysis of heart rate in hypertensive patients with and without left ventricular mass reduction

Power spectral analysis of heart rate in hypertensive patients with and without left ventricular mass reduction

Coronary and total peripheral resistance changes during sleep in a porcine model.

Changes in autonomic tone in the vasculature during sleep may have important implications for silent ischemia and sudden cardiac death. Few models exist in which both cardiac output and coronary blood flow are continuously measured during natural sleep and autonomic mechanisms are assessed. Catheters were chronically implanted in the aorta to measure mean arterial pressure (MAP), and flow probes were placed on the ascending aorta and the circumflex coronary artery of 18 pigs. Electrodes determined sleep stage as either non-rapid eye movement (NREM) or rapid eye movement (REM) sleep. The MAP was 73 +/- 3 mmHg in the quiet awake state, did not change in NREM, and decreased to 64 +/- 2 mmHg in REM sleep (P < 0.05). In NREM sleep, heart rate did not change from awake state values of 136 +/- 8 beats/min but increased by 5 beats/min in REM sleep (P < 0.05). Coronary vascular resistance decreased from awake state values of 2.7 +/- 0.2 to 2.2 +/- 0.2 mmHg.ml-1.min in REM (P < 0.05); total peripheral resistance decreased from awake values of 0.061 +/- 0.004 mmHg.ml-1.min to 0.050 +/- 0.003 in REM sleep (P < 0.05). Those changes appear to have been mediated primarily by reduction of alpha-adrenergic activity. Spectral analysis of heart rate suggests that power in the high-frequency range (a presumed indicator of parasympathetic tone) was lower in REM sleep than NREM sleep.

Power Spectral Analysis of Heart Rate in Elderly Hypertensive Subjects With or Without Silent Coronary Disease

Much evidence indicates an involvement of the sympathetic nervous system in the genesis of silent myocardial ischemia. The authors assessed autonomic system activity by power spectrum analysis of heart rate variability in 21 elderly hypertensive men with and without angiographically confirmed coronary artery disease and compared the results with those from an age-matched control group. In the analysis an autoregressive algorithm was used to determine the power spectrum from an electrocardiographic recording of 512 consecutive RR intervals. The autonomic nervous system induces two distinct sinusoids: a low-frequency signal attributable to sympathetic activity and a high-frequency vagal response. In the hypertensive patients with coronary disease the authors also evaluated sympathetic activation after double-blind, placebo-controlled administration of metoprolol (100 mg/day), followed by amlodipine (10 mg/day), quinapril (20 mg/day), and amlodipine (5 mg/day) plus quinapril (10 mg/day).

Ｓｌｅｅｐ Ｃｙｃｌｅの定量評価について

In order to analyze the sleep cycle in human natural sleep, physiological parameters were recorded from healthy adult subjects. Utilizing the spectral analysis of heart rate, autonomic state during sleep was investigated. Specific changes of LF and HF component of the spectra were observed in each sleep stage.