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The sympathetic nervous system overdrive occurring in heart failure has been reported for more than half a century. Refinements in the methodological approaches to assess human sympathetic neural function have allowed during recent years to better define various aspects related to the neuroadrenergic alteration. These include (i) the different participation of the individual regional sympathetic cardiovascular districts at the process, (ii) the role of the central nervous system in determining the neuroadrenergic overdrive, (iii) the involvement of baroreflex, cardiopulmonary reflex, and chemoreflex mechanisms in the phenomenon, which is also closely linked to inflammation and the immune reaction, (iv) the relationships with the severity of the disease, its ischaemic or idiopathic nature and the preserved or reduced left ventricular ejection fraction, and (v) the adverse functional and structural impact of the sympathetic activation on cardiovascular organs, such as the brain, the heart, and the kidneys. Information have been also gained on the active role exerted by the sympathetic activation on the disease outcome and its potential relevance as a target of the therapeutic interventions based on non-pharmacological, pharmacological, and invasive approaches, including the renal denervation, the splanchnic sympathetic nerve ablation, and the carotid baroreflex stimulation. The still undefined aspects of the neurogenic alterations and the unmet goals of the therapeutic approach having the sympathetic activation as a target of the intervention will be finally mentioned.

Purpose of the study. Investigate changes of cardiac hemodynamic parameters caused by ocular cardiac reflex triggering in healthy men’s in youthful age. Material and methods. 120 healthy male volunteers in youthful age were examined. The mean age was (19,2 ± 0,93 years). For ocularcardiac reflex (OCR) triggering we used a patented model «Device for dosed compression effects on the eyeballs» and «The method of ocular cardiac reflex triggering». On the basis of the obtained parameters of systolic (SBP) and diastolic (DBP) blood pressure, by arithmetic operations, pulse pressure (PP) and average flow pressure (AFP) and integrative parameters of cardiohemodynamics (CHD) – systolic blood volume (SBV), minute blood flow volume (MBFV), volumetric blood flow rate (V), total peripheral resistance (TPR) were determined. Results. Three main types of cardiovascular system response on OCR triggering were identified. The first type – hypertensive (n = 30 (25%) of the total number of examined subjects) was characterized by a significant (p < 0,05) increase in heart rate, SBP, DBP, PP, AFP and other integrative parameters of CHD. The second, hypotonic type of the response (62 subjects; 51,7%) was characterized by a significant (p < 0,05) decrease in SBP, DBP, PP, AFP. Patients with third, dystonic type, of response (n = 28 (23,3%) of the total number examined subjects) showed significant bilateral changes of blood pressure parameters in a nonlinear dependence of compression power on the eyeballs. Determination CHD parameters directly after and 3 and 5 minutes after decompression of the air in the compression device we enabled to determine the subtype of the mobility of the nervous centers as a feature that complements the basic type. The subtype of normal mobility was revealed in 63,3% (n = 19) of subjects with the main hypertensive type of response, 69,3% (n = 43) of subjects with the main hypotonic and 60,7 % (n = 17) with the main dystonic type of response of the cardiovascular system. The inert subtype in the mobility of the cardiovascular system were identified in 36,7% (n = 11) individuals with hypertension is the main type of response, at 30,7% (n = 19) of individuals with primary hypotonic type of response and 39,3 % (n = 11) – distancing. The obtained typological changes in blood pressure parameters caused by OCR triggering allowed to reveal predisposition to hypertension, hypotension, dystonia and to predict the development of hypertension in patients with hypertensive type of response usin appropriate primary prevention changes in life style. The highest risk of hypertension development may be in persons with hypertensive inert type of reaction of the system of regulation of blood pressure on OCR triggering. Further studies are being conducted to confirm this assumption.

Is another person's direct gaze an inherently positive or negative stimulus? The present study employed the startle reflex methodology to investigate individuals' automatic reactions to another person's direct and averted gaze. In the study, participants' eyeblink startle and cardiac reflexes elicited by a high-intensity acoustic noise stimulus were measured in the context of viewing a live model's direct and downward gaze. Both the eyeblink electromyographic and electrocardiographic data revealed that the startle reflex was modulated by gaze direction. Direct gaze attenuated the eyeblink startle and cardiac reflexes to the acoustic probes compared to those elicited in the context of a downward gaze. These results indicate that the defense reflex is weaker when presented in the context of direct versus downward gaze, and thus suggest that another individual's direct gaze, compared to averted gaze, automatically elicits more positive affective responses in the viewer.

With the aim of studying the features of the vegetative components of cardiac activity in the period of functional stress of the body, that are interesting for study of adaptive changes in the human circulatory system, there has been studied the heart chronotropic response to the paired somato-vegetative cardiac reflex caused by a modified breakdown Aschner-Danini in first year military servicemen and students of the Syktyvkar State University in conditions of relative rest and after physical loading, samples Martin-Kushelevsky. With use of the method of electrocardiography in the second standard lead, there were recorded RR-intervals before and after functional tests. It has been found that in the servicemen with the heart heterogeneous chronotropic function which bodies adapted to new environments, vagal samples in the body state of relative rest caused a bigger heterogeneous chronotropic response of the heart than in the students adapted to external conditions. After the subjects underwent exercise loading, the heart response to induced coupled cardiac reflex was unidirectional and more pronounced than at rest. The results indicated increased influence of the vagus on the heart work in conditions of the body mobilization. Associated vagal test combined with the exercise loading is the method of choice in evaluation of the autonomic system regulating the circulation homeostasis in conditions of high requirements to the body.

Sleep bruxism is classified as a repetitive jaw-muscle activity characterized by clenching or grinding and/or bracing or thrusting of the mandible during sleep. It has been proposed that sleep disordered breathing is causative regarding sleep bruxism, in a protective roll, assisting in stabilization of the airway during these abnormal breathing events. This paper will attempt to present evidence of two distinct forms of sleep bruxism: primary and secondary. It has been shown that sleep bruxism stimulates the trigeminal cardiac reflex affecting heart rate, respiration, blood pressure and cranial pressure. This paper compares the similarities and differences between primary sleep bruxism (occurring independently), secondary sleep bruxism occurring with sleep disordered breathing and secondary sleep bruxism resulting from administration of selective serotonin reuptake inhibitor type medications. It also examines how they all affect the trigeminal cardiac reflex similarly and meet the most recent classification of trigeminal cardiac stimulation.

The defensive cardiac reflex (DCR) is a reaction of the cardiovascular system with a specific profile of short- and long-latency reactivities (mainly of arterial blood pressure (BP) and heart rate (HR)). The DCR reflects activation of the defensive motivational system and defensive coping programs in humans. The aim of the present work was to evaluate the contribution of the brain oscillatory systems to the mechanisms of individual variability of the DCR. The oscillatory dynamics of multichannel (64-channel) electroencephalogram (EEG) were assessed using evoked synchronization/desynchronization in different frequency ranges and hemodynamics were assessed using simultaneously recorded beat-by-beat measures of cardiovascular reactivity (Finapres® technology). This is the first report showing significant linkage between θ2 (6–8 Hz) EEG activity with short-latency DCR reactivity and between α2 (10–12 Hz) activity and long-latency reactivity. Hyperreactivity of the long-latency BP component was shown to be associated with the absence of a concomitant phase α2 synchronization evoked. It is suggested that high-frequency θ EEG oscillations are involved in the central magnitude scaling mechanisms and that α2 oscillations have a role in top-down inhibitory control of short- and long-latency stress reactivity of BP in the DCR.

OBJECTIVE The aim of the present study was to comprehensively compare noninvasive and invasive blood pressure (BP) measured by the Philips Intellivue MP50 monitor in surgeries that may induce gall cardiac reflex under general anesthesia. PARTICIPANTS AND METHODS Seventy-eight patients undergoing cholecyst or bile duct operations under general anesthesia were enrolled in our study. Both invasive (intraradial, femoral, or dorsalis pedis artery) and noninvasive (oscillometric) BP were monitored by the Philips Intellivue MP50 monitor simultaneously. Data were analyzed using Bland-Altman plots. RESULTS In a supine position during operations, between intraradial and oscillometric measurements, the bias and precision (mmHg) were 9.34±12.98 and 12.47±10.00 for systolic blood pressure (SBP) and 3.26±8.22 and 6.53±5.97 for diastolic blood pressure (DBP), between intrafemoral and oscillometric measurements, the bias and precision (mmHg) were 14.40±14.38 and 16.93±11.28 for SBP and 4.35±9.72 and 7.52±7.54 for DBP, between intradorsalis pedis and oscillometric measurements, the bias and precision (mmHg) were 15.69±14.37 and 16.91±12.91 for SBP and 0.99±7.69 and 5.67±5.27 for DBP. CONCLUSION The oscillometric BP showed poor agreement with intra-arterial BP in cholecyst or bile duct surgeries that may induce gall cardiac reflex under general anesthesia. Therefore, according to the present data, application of oscillometric BP measured by the Philips Intellivue MP50 monitor in these surgery patients under general anesthesia cannot be recommended generally.

Summary This case study examines the onset of traumatic OCR – Oculo-cardiac Reflex – in the remote southern highlands of PNG. The spontaneous occurrence of OCR post-trauma in the clinical setting leads to sudden onset bradycardia, nausea and hypotension, resulting in cardiovascular compromise and deteriorating clinical conditions. Initial recognition of the characteristics of OCR will prepare the clinician to deal with the sequence of events that arise post the reflex initiation.

Introduction: Dentocardiac reflex, a variant of trigeminocardiac reflex elicited specifically during tooth extraction procedures in den-tal/maxillofacial surgery and is believed to cause syncope with an afferent link mediated by posterior superior alveolar nerve. Another variant of trigeminocardiac reflex which is also of interest to the oral and maxillofacial surgeon is oculocardiac reflex which can be triggered by direct or indirect manipulation of eye globe or muscles around it.The hypothesis: Excessive or injudicious pressure or manipulations around the maxillary first molars during extraction procedure are as-sociated with maximum incidence of bradycardia and hypotension than around incisor/ canine/ third molars. This is because; the pressure on eye globe and ophthalmic rectus muscle is maximum during extraction of first molar than incisor/canine and third molars. This observation led us to postulate an alternative pathway for dentocardiac reflex mediated syncope which may possibly justify the maxillary first molar region as a prone factor for the trigger. Evaluation of the hypothesis: Present hypothesis may not confer the specific factor responsible for switch in autonomic response in syncope origin during the tooth extraction procedure, but may provide a clue to where we should be looking.

Resume Objectif. – Evaluer l’efficacite de l’ECG spectral par rapport au monitorage conventionnel de la frequence cardiaque dans la detection des reactions vagales induites par les stimuli neurochirurgicaux. Methodes. – Vingt patients (âge : 65 ± 13 ans; Asa : II–III) candidats a une chirurgie de l’angle pontocerebelleux ou de pose d’un neurostimulateur sacre ont ete inclus. L’anesthesie intraveineuse a objectif de concentration (propofol : 2–4 μg ml –1 , remifentanil : 4 ng ml –1 ) a ete realisee sous controle de l’index bispectral de l’electro-encephalogramme (Bis). L’ECG spectral a ete obtenu grâce au logiciel (Labview™, National Instruments, Etats-Unis) d’un ordinateur connecte au moniteur cardiorespiratoire. L’intervalle R–R etait decompose (selon la transformee de Fourier rapide) en spectres de basses frequences (LF : 0,04–0,15 Hz) et de hautes frequences (HF : 0,15–0,4 Hz) correspondant, respectivement, aux activites sympathique et parasympathique. La pression arterielle par catheterisme radial, la SpO 2 , la fraction expiree de CO 2 et la temperature ont ete enregistrees de facon continue. La reaction vagale etait definie par une augmentation de HF et diminution de FC > 10 % de la valeur avant le stimulus chirurgical. La concordance entre FC et HF etait fondee sur un coefficient de kappa ( k ) : –1 = discordance totale a 1 = concordance totale. Le delai de detection de HF et FC etait compare par un test de Student avec p Resultats. – Douze reactions vagales (observees chez 8 patients) ont ete detectees dans un delai de : 5,5 ± 1,3 s (pour HF) et 12,4 ± 1,6 s (pour la FC) ; p κ = 0,9). Conclusion. – l’ECG spectral est une technique non invasive permettant la detection des reactions vagales de maniere plus precoce que le monitorage conventionnel de la FC.

Background Hemodynamic perturbations in spine surgeries are predominantly reported in cervical and thoracic level procedures. The literature related to negative cardiovascular changes (decrease of heart rate and blood pressure) in lumbar spine procedures is still scarce and only highlighted in few case reports/letters until now. Methods With the help of a systematic literature review with predefined criteria, we, therefore, examined and synthesized here the probable underlying common cause of these hemodynamic disturbances in lumbar spine surgeries. Data aggregation to a model was done by a case survey method and established by a cause-effect relationship. Results There are only 5 cases that met our strict predefined criteria and that were aggregated to an emergent model of an autonomous reflex arc. Conclusion This review and consecutive data aggregation provides, for the first time, a concept of spinal cardiac reflex in lumbar spine surgeries.

Summary Rhythmic body movements and their role as triggers of intermittent heartbeats were studied in pupae of Leptinotarsa decemlineata Say. Heartbeats and body movements were recorded simultaneously by means of an optical method (infra-red cardiography) combined with respirometry. IR-cardiography allows heartbeats and body movements to be distinguished on the basis of their different rates (40–80 min−1 and 4–8 min−1, respectively) and amplitude. In the mid-interecdysial period, abdominal movements in the pupae were always accompanied by heart activity beginning after the first 5–12 abdominal strokes. Simultaneous periods of abdominal movements and heartbeats lasted 2–5 min, while the intervening pause ranged from 40 to 72 min at 24°C. Experiments of forced heart activity showed that a slight external tactile stimulus (prodding once with a single hair), applied prior to an expected heartbeat bout, evoked abdominal movements followed soon afterwards by contractions of the dorsal vessel. Repeated prodding with a hair evoked body rotating movements (1–3 strokes) at any time with heartbeats starting at the first movement. We surmise that rhythmic body movements play an active role in the triggering of heart activity in pupae according to the principle of cardiac reflex response. This is a possible mechanism for synchronizing periods of heart activity with periods of rhythmic body movements. Haemolymph circulation in pupae is favoured when heartbeat bouts are accompanied by active body movements.

We investigated the aortic-cardiac reflex during low-intensity cycling in 10 healthy volunteers. Baroreflex function was assessed by the ratio of change in heart rate to mean arterial pressure (delta HR/delta MAP) during phenylephrine (PE) infusion. The ratio obtained during PE combined with low-level lower body negative pressure (LBNP) and calculated neck pressure (NP) was assessed as the gain of the aortic-cardiac reflex. Exercise (approximately 25% maximal O2 uptake or 25 +/- 2 W) significantly increased HR from 64 +/- 2 to 98 +/- 2 beats/min, MAP from 90 +/- 3 to 98 +/- 3 mmHg, cardiac output from 6.6 +/- 0.5 to 12.0 +/- 1.4 l/min, and O2 uptake from 3.8 +/- 0.2 to 10.4 +/- 0.6 ml.min-1.kg-1. However, delta MAP (+11.8 +/- 0.4 vs. + 11.3 +/- 0.8 mmHg), delta HR (-12.7 +/- 2 vs. -12.9 +/- 2 beats/min), and delta HR/delta MAP (1.10 +/- 0.19 vs. 1.15 +/- 0.15 beats.min-1.mmHg-1) were not statistically different between rest and exercise during PE. Although PE significantly increased central venous pressure in both supine rest (from 6.7 +/- 0.7 to 10.4 +/- 0.7 mmHg) and exercise (5.8 +/- 0.8 to 8.6 +/- 0.9 mmHg) conditions, when LBNP (-15 +/- 2 vs. -16 +/- 1 Torr for rest vs. exercise) was applied, both rest and exercise central venous pressures were returned to the preinfusion baseline values, respectively.(ABSTRACT TRUNCATED AT 250 WORDS)

This study aimed at replicating and extending previous results on the association between baroreceptor reflex sensitivity (BRS) and cognitive performance. Thirty men and 31 women performed an arithmetic task. After adjusting for numerical aptitude and effort, no predictors of performance were found in men. In women, the relationships between BRS and parameters related to correct responses were modulated by blood pressure (BP). BRS was inversely associated with these parameters for participants with BP>1 SD above the mean, whereas the associations were positive in participants with BP

The work-related strain of 50 female hospital cleaners and 48 female bank employees was recorded during a period of rationalization in the workplace, and the effect of daily relaxation to help the workers cope was tested. The subjects were arranged into age-matched pairs and randomly allocated into intervention and reference groups. The intervention period lasted six months. The relaxation method was brief and easily introduced as an alternative break in the workplace. Each training session lasted 15 min. A microcomputer-based system was used to record heart rate variability in response to quiet breathing, the Valsalva maneuver, deep breathing, and active orthostatic tests. Cardiac reflexes indicated that occupational strain (especially of a mental nature) caused the functioning of the autonomic nervous system to deteriorate. Regular deep relaxation normalized the function and improved the ability to cope.

Baroreceptor reflex sensitivity (BRS) is frequently evaluated using the spontaneous sequence method. Many of these studies use the inter-systolic interval (ISI) derived from a blood pressure monitor (e.g., Finapres) as interbeat interval measure instead of the traditionally recommended R-R series derived from the ECG. In this study, we examine possible differences between estimates of BRS from ISI and ECG R-R intervals. BRS was evaluated in 35 participants under three conditions: rest, mental arithmetic, and recovery periods. Although correlations between the two estimates are very high (all rs>.9), small but significant differences were found: the measures from ISI systematically yield higher BRS values and result in the detection of a greater number of reflex sequences. The higher BRS values from measures of ISI are due to the effects of pulse transit time fluctuations associated with the sequences of change in blood pressure.

To determine the role of cardiac reflexes in mediating exercise hyperpnea, we investigated ventilatory responses to treadmill exercise in seven calves with artificial hearts and seven controls. In both groups, the ventilatory responses were adequate for the metabolic demands of the exercise; this resulted in regulation of arterial PCO2 and pH despite the absence of cardiac output increase in the implanted group. In this group, there was a small but significant reduction of arterial PO2 by 4 +/- 3 Torr and a rise of blood lactate by 1.1 +/- 1 mmol/l. When cardiac output was experimentally increased in the implanted calves to a level commensurate with that spontaneously occurring in the control calves, ventilation was not affected. However, experimental reductions of cardiac output led to an immediate augmentation of exercise hyperpnea by 4.56 +/- 4.3 l/min and a further significant lactate increase of 1.2 +/- 1.22 mmol/l that was associated with a significant decrease in the exercise O2 consumption (0.32 +/- 0.13 l/min). These observations indicate that neither cardiac nor hemodynamic effects of increased cardiac output constitute an obligatory cause of exercise hyperpnea in the calf.

The concept of defense relates to the idea that organisms react physiologically to the presence of danger or threat in order to protect themselves from potential injury or death. This article reviews the literature on cardiac defense, a specific defense reaction that has a long tradition in psychophysiological research. The review begins with a brief analysis of the two traditional approaches to understand this autonomic response: the cognitive -- linked to Pavlov, Sokolov, and Graham's work on sensory reflexes -- and the motivational -- linked to Cannon and Selye's work on the concepts of activation and stress. Then, the classic model of cardiac defense and its basic assumptions concerning differentiation from other cardiac reflexes -- namely orienting and startle -- are presented. A critical analysis of these assumptions follows centered on evidence from a systematic research of the cardiac response to intense acoustic stimulation. Finally, an integrative model of cardiac defense is presented which emphasizes the dynamic nature of this defense reaction - characterized by a complex pattern of heart rate changes with accelerative and decelerative components, with sympathethic and parasympathetic influences, and with both attentional and motivational significance - providing a new framework in which the two opposite traditional approaches can be reconciled.

The present study tested the hypothesis that increased plasma brain natriuretic peptide (BNP) levels are related to cardiac autonomic dysfunction in type 2 diabetic patients. A total of 32 consecutive Japanese patients with type 2 diabetes were assigned to either a high-BNP (or=18 pg/ml) group (n=12; age 57+/-13 years, mean+/-S.D.) or a normal-BNP (18 pg/ml) group (n=20; 59+/-10 years). No patient had any overt structural heart disease. Cardiac autonomic function was assessed by measurements of baroreflex sensitivity (BRS), heart rate variability (HRV) and cardiac (123)I-metaiodobenzylguanidine (MIBG) scintigraphic findings. BRS was lower (p0.005) in the high-BNP group than in the normal-BNP group. However, the components of HRV, and the early and delayed myocardial uptake of (123)I-MIBG and percentage washout rate of (123)I-MIBG were not significantly different between the groups. The plasma level of BNP negatively correlated with BRS (r=0.35, p=0.049). These findings suggest that increased plasma BNP levels were related to cardiac reflex parasympathetic dysfunction in our Japanese type 2 diabetic patients.

This paper describes a computer program for the noninvasive evaluation in the time domain of the part of the baroreceptor reflex that relates blood pressure to interbeat interval from spontaneous hemodynamic patterns in which the reflex is operating. The program obtains the sensitivity of the baroreceptor reflex (slope of the regression line between the interbeat interval and systolic blood pressure in msec/mmHg) and an index of the baroreceptor power to regulate cardiac activity. These statistics are obtained differentially both when the systolic blood pressure is increasing and when it is decreasing. The results obtained by using this software during a mental load task were compared with those obtained through spectral analysis.

Previous experimental results have suggested the existence of a local cardiac reflex in the rat. In this study, the putative role of such a local reflex in cardiovascular regulation is quantitatively analyzed. A model for the local reflex is developed from anatomical experimental results and physiological data in the literature. Using this model, a systems-level analysis is conducted. Simulation results indicate that the neuromodulatory mechanism of the local reflex attenuates the nonlinearity of the relationship between cardiac vagal drive and arterial pressure. This behavior is characterized through coherence analysis. Furthermore, the modulation of phase-related characteristics of the cardiovascular system is suggested as a plausible mechanism for the nonlinear attenuation. Based on these results, it is plausible that the functional role of the local reflex is highly robust nonlinear compensation at the heart, which results in less complex dynamics in other parts of the reflex.

Experimental efforts in th authors' group have suggested the existence of local cardiac reflex in the rat. In this study, the putative role of such a local reflex in cardiovascular regulation is analyzed. A model for the local reflex based on the anatomical results and physiological and pharmacological data from other labs and literature is developed. Using this model, a systems level analysis is conducted. Simulation results indicate that the neuromodulatory mechanism of the local reflex attenuates the nonlinearity of the relationship between cardiac vagal drive and arterial pressure. Based on these results, it is plausible that the functional role of the local reflex is highly robust nonlinear compensation at the heart, which results in less complex dynamics in other parts of the reflex.

Coupling of locomotor and cardiac cycles has been suggested to facilitate effective arterial delivery and venous return during vigorous exercise. In an attempt to document locomotor-cardiac coupling, we ran five dogs on a motorized treadmill while monitoring heart activity with surface electrocardiogram electrodes and locomotor events with high-speed video and an accelerometer mounted on the dog’s back. Analysis of the cardiac and locomotor frequencies revealed that heart rate was usually slightly greater than stride frequency. Hence the timing of the cardiac cycles varied with respect to the phase of the locomotor cycles, and therefore consistent coupling of the locomotor and cardiac cycles was not observed in any of the dogs. However, the period of the cardiac cycle sometimes varied in a rhythmic way that caused brief periods of transient coupling of the locomotor and cardiac cycles in three of the five dogs. These brief periods of coupling (5–20 heartbeats) occurred at approximately the same phase relationship in each of the three dogs. We hypothesize that the variation in cardiac period and the resulting transient coupling are a function of locomotor and ventilatory influences on venous return and/or ventricular ejection. Because venous return and ejection fraction are likely to vary in an unpredictable manner when animals run in a complex environment, we suggest that reflex control of heart rate will be important during locomotion and strict integer coupling of the locomotor and cardiac cycles is unlikely to evolve.