ETS affects the ANS and emotional integration: Cerebral sympathetic nerve activity has a major regulatory role in the cerebral circulation in REM sleep

It’s not unusual to hear people describe themselves as emotionally 'colder'

It’s not unusual to hear people who have undergone sympathectomies describe themselves as feeling emotionally “colder” than before. Among psychologists and neurologists alike there is concern, but no evidence, that the procedure limits alertness and arousal as well as fear, and might affect memory, empathy and mental performance. Professor Ronald Rapee, the director of the Centre of Emotional Health at Sydney’s Macquarie University, says he’s counselled several people who complain of feeling “robot-like” in the long-term wake of the operation. “They’re happy they no longer blush, but they miss the highs and lows they used to feel.”
(John van Tiggelen, Good Weekend Magazine, The Age and the Sydney Morning Herald, 10th March 2012)

https://archive.today/uURge

Saturday, 5 July 2014

Cerebral sympathetic nerve activity has a major regulatory role in the cerebral circulation in REM sleep

Cassaglia PA, Griffiths RI, Walker AM.

Source

Ritchie Centre for Baby Health Research, Monash Institute of Medical Research, Monash University, Melbourne, Australia.

Abstract

Sympathetic nerve activity (SNA) in neurons projecting to skeletal muscle blood vessels increases during rapid-eye-movement (REM) sleep, substantially exceeding SNA of non-REM (NREM) sleep and quiet wakefulness (QW). Similar SNA increases to cerebral blood vessels may regulate the cerebral circulation in REM sleep, but this is unknown. We hypothesized that cerebral SNA increases during phasic REM sleep, constricting cerebral vessels as a protective mechanism against cerebral hyperperfusion during the large arterial pressure surges that characterize this sleep state. We tested this hypothesis using a newly developed model to continuously record SNA in the superior cervical ganglion (SCG) before, during, and after arterial pressure surges occurring during REM in spontaneously sleeping lambs. Arterial pressure (AP), intracranial pressure (ICP), cerebral blood flow (CBF), cerebral vascular resistance [CVR = (AP - ICP)/CBF], and SNA from the SCG were recorded in lambs (n = 5) undergoing spontaneous sleep-wake cycles. In REM sleep, CBF was greatest (REM > QW = NREM, P < 0.05) and CVR was least (REM < QW = NREM, P < 0.05). SNA in the SCG did not change from QW to NREM sleep but increased during tonic REM sleep, with a further increase during phasic REM sleep (phasic REM > tonic REM > QW = NREM, P < 0.05). Coherent averaging revealed that SNA increases preceded AP surges in phasic REM sleep by 12 s (P < 0.05). We report the first recordings of cerebral SNA during natural sleep-wake cycles. SNA increases markedly during tonic REM sleep, and further in phasic REM sleep. As SNA increases precede AP surges, they may serve to protect the brain against potentially damaging intravascular pressure changes or hyperperfusion in REM sleep.

Comment in

Have a safe night: intimate protection against cerebral hyperperfusion during REM sleep. [J Appl Physiol. 2009]

No comments:

autonomic vulnerability or visceral dysfunction may precipitate or aggravate mental symptoms

Hemodynamic changes in vertebral and carotid arteries were observed after sympathicotomy

T3 sympathicotomy segment was the most frequent transection done (95.83%), as only ablation (25%) or in association with T4 (62.50%) or with T2 (8.33%). It was observed increase in RI and PI of the common carotid artery (p <>CONCLUSIONS: Hemodynamic changes in vertebral and carotid arteries were observed after sympathicotomy for PH. SPV was the most often altered parameter, mostly in the right side arteries, meaning significant asymmetric changes in carotid and vertebral vessels. Therefore, the research findings deserve further investigations to observe if they have clinical inferences.
http://www.ncbi.nlm.nih.gov/pubmed/16186983

A neurotransmitter involved in emotional arousal enhances learning

Do you remember the song that was playing during your first kiss? Both positive and negative emotions influence learning and memory but researchers have not determined the mechanism. Now Hu et al. report that the neurotransmitter norepinephrine regulates glutamate receptor trafficking in a recent article in Cell.

Axon terminals containing norepinephrine synapse in the hippocampus and amygdala, which are important in emotional memory. In the hippocampus, norepinephrine reduces the threshold for long-term potentiation (LTP), which is thought to be a substrate of memory. Norepinephrine acts at beta-adrenergic receptors, where it activates cAMP-dependent protein kinase (PKA) and calcium/calmodulin-dependent protein kinase II (CaMKII). These kinases phosphorylate serines 845 and 831, respectively, in the AMPA glutamate receptor type 1 (GluR1). The authors proposed that norepinephrine regulates learning by phosphorylating AMPA receptors. Hu, H. et al. Emotion enhances learning via norepinephrine regulation of AMPA-receptor trafficking.

Cell 131, 160–173 (2007). | Article | PubMed | Emotional intelligence Neuroscience Gateway (October 2007) | doi:10.1038/aba1787

'Emotional' sweating regulated by neocortex and limbic cortex

Careful observations showed that the forearm sweating responded diversely to various mental stimuli, unlike the palmar sweating whose response was always an increase. Mental arithmetic, mental testing and physical exercise caused an immediate increase in the palmar sweating but often elicited a transient decrease in the forearm sweating, whereas pain, noise, and emotional stimuli consistently provoked an increase of sweating on the forearm as well as on the palm. These observations suggest that the activities of higher centers, presumably involving neocortex and limbic cortex, exert various influences on the central mechanisms of palmar and generalized sweating. Jpn J Physiol. 1975;25(4):525-36. http://www.ncbi.nlm.nih.gov/pubmed/1206808

acute response to denervation and abrupt release of sympathetic tone following sympathectomy

Sympathectomy - a medical fraud: sympathectomy created imbalance of autonomic activity and functional changes of the intrathoracic organs: "acute response to denervation and abrupt release of sympathetic tone following sympathectomy
Intraoperative predictability of successful outcome depends on monitoring of the ae response to surgical denervation and abrupt release of sympathetic tone.

Information on the long-term physiological sequelae is emerging rapidly."

DIAGNOSIS AND TREATMENT OF HYPERHIDROSIS, CONCISE REVIEW CLINICIANS
Mayo Clin Proc. • May 2005;80(5):657-666

remarkable changes in the nerves that remain

Chemical denervation and selected ganglionectomy studies have shown that loss of sympathetic or sensory innervation induces remarkable changes in the nerves that remain.

The loss of sympathtetic neurones and nerve fibres is also accompanied by striking increases in sensory innervation. This has been attributed to increased availability to NGF (as there are no sympathetic nerves with which to compete for uptake) which promotes the growth of sensory nerves (Kessler et al. 1983)

In the lung, sympathectomy induced a marked increase in CGRP-immunoreactive nerve density around the airways, and blood vessels.
The Autonomic Nervous System. Part I. Normal Functions by O. Appenzeller (Hardcover - Dec 1, 1999)
Category: Neurology & Clinical Neurophysiology

Publication Date: 1999-12-16 Publisher: Elsevier - Health Sciences Div

second thoracic sympathetic ganglion was most commonly located (50%) in the second intercostal space

anatomic variations of the T2 nerve root

6 (9.1%) sides showed a single large ganglion formed by the stellate and the second thoracic sympathetic ganglia. The second thoracic sympathetic ganglion was most commonly located (50%) in the second intercostal space. Conclusion: The anatomic variations of the intrathoracic nerve of Kuntz and the second thoracic sympathetic ganglion were characterized in human cadavers. Journal of thoracic and cardiovascular surgery Y. 2002, vol. 123, No. 3, pages 498-501 [bibl. : 14 ref. http://www.refdoc.fr/Detailnotice?idarticle=9466218

decreased conditioning-related activity in insula and amygdala

decreased conditioning-related activity in insula and amygdala in patients with autonomic denervation

The degree to which perceptual awareness of threat stimuli and bodily states of arousal modulates neural activity associated with fear conditioning is unknown. We used functional magnetic neuroimaging (fMRI) to study healthy subjects and patients with peripheral autonomic denervation to examine how the expression of conditioning-related activity is modulated by stimulus awareness and autonomic arousal. In controls, enhanced amygdala activity was evident during conditioning to both "seen" (unmasked) and "unseen" (backward masked) stimuli, whereas insula activity was modulated by perceptual awareness of a threat stimulus. Absent peripheral autonomic arousal, in patients with autonomic denervation, was associated with decreased conditioning-related activity in insula and amygdala. The findings indicate that the expression of conditioning-related neural activity is modulated by both awareness and representations of bodily states of autonomic arousal.
http://www.ncbi.nlm.nih.gov/pubmed/11856537

sympathectomy may retard aversive conditioning

"Researchers have examined the role of autonomic feedback in emotional experience using the heartbeat paradigm. Katkin at al. (1982) found that some normal subjects can accurately detect their heartbeats, and it was those individuals who had a stronger emotional response to negative slides as determined by self-report (Hantas et al., 1982). Further support for the importance of autonomic feedback comes from observations. Experiments in animals demonstrate that sympathectomy may retard aversive conditioning (DiGusto and King, 1972), most likely because sympathectomy reduces fear.

In order for a feedback to occur, there must be a means for the viscera and autonomic nervous system to become activated.
Clinical neuropsychology
By Kenneth M. Heilman, Edward Valenstein
Oxford University Press

CARDIOVASCULAR CHANGES POST SYMPATHECTOMY

Behavioral changes after sympathectomy

Six experiments are reported on the effects of 2,4,5-trihydroxyphenylethyl-amine (6-hydroxydopamine) on two-way escape and avoidance learning. Rats were tested on either escape or avoidance learning at 80 days of age after chemical sympathectomy at birth or 40 or 80 days of age. Neonatal and chronic sympathectomy (at 40 days), but not acute sympathectomy (at 80 days), resulted in depressed escape learning. Avoidance learning was affected by neonatal sympathectomy and partially by acute sympathectomy. The results have implications for the role of the autonomic nervous system in escape-avoidance learning.
J Comp Physiol Psychol 1976; 90:303-16.

decrease in CBF induced by sympathectomy cannot be attributed to hypersensitivity

Thus the decrease in CBF induced by chronic sympathectomy cannot be attributed to the development of hypersensitivity to catecholamines. This decrease remained stable whatever the value of resting flow and was maintained under anesthesia. It is concluded that, as in the peripheral circulation, chronic sympathectomy affects the equilibrium of the vascular smooth muscle fibers, but that circulating amines play no compensatory role in the cerebral circulation because of the blood-brain barrier.

http://www.sciencedirect.com/science/article/pii/0006899385902434

The sympathetic nervous system is responsible for the physiological responses to emotional states

The common epithet of “fight or flight” is being enlarged to be “fight, flight, or fright” or even “fight, flight, fright, or freeze.” Cannon’s original contribution was a catchy phrase to express some of what the nervous system does in response to a threat, but it is incomplete. The sympathetic system is responsible for the physiological responses to emotional states. The name “sympathetic” can be said to mean that (sym- = “together”; -pathos = “pain,” “suffering,” or “emotion”). http://cnx.org/content/m46582/latest/?collection=col11496/latest

Psychoneurological applications of endoscopic sympathetic blocks

In addition to more widely and longer known indications of ETS, various neurological disorders and psychologically stressful situations in their worst expressions might be alleviated by the reversible ESB procedure. The patients with social phobia, especially those who have also blushing and/or stage fright type of heart racing, benefit from the ESB. The disturbances of the sympathetic nervous system, e. g. in Parkinson's disease and multiple system atrophy might be alleviated with sympathetic block, especially the extrapyramidal symptoms in these diseases. In migraine, sympathetic surgery has been noted to give some help. The unilateral left-sided block has been effective in long QT-syndrome type arrhythmias. In schizophrenia, the phobic, paranoic or confusional reactions have been tentatively treated by the sympathetic block.
Clin Auton Res. 2003 Dec;13 Suppl 1:I20-1; discussion I21.

Impaired autonomic function results in impaired cerebral regulation

The absence of an increase in the power of 0.1 Hz blood pressure and cerebral blood flow velocity oscillations confirmed autonomic neuropathy in the diabetic patients. Gain analysis did not show altered cerebral regulation. The decrease in phase shift in the patients indicates a more passive transmission of neck suction-induced blood pressure fluctuations onto the cerebrovascular circulation, i.e. altered cerebral regulation, in the patients, and is therefore suited to identifying subtle impairment of cerebral regulation in these patients.
http://www.springerlink.com/content/14m7g478j7ux11hv/

sympathectomy resulted in complete disappearance of adrenergic and decrease of cholinergic fibers

sympathectomy resulted in complete disappearance of histochemically detected adrenergic and a considerable decrease of cholinergic nerve fibers in the pial arterial walls. The vasodilatation was much less obvious in sympathectomized than in control animals. This was associated with (and probably caused by) a considerable rise in histochemically detected serotonin activity of the pial arteries walls. After recovery of blood supply to the brain the constriction of the pial arterial active segments restricting the excessive cerebral blood flow, was significantly reduced due, probably, to the sympathetic deprivation. Therefore, the sympathetic control plays an important part in pial arterial responses regulating the adequate blood supply of the cerebral cortex.
http://www.ncbi.nlm.nih.gov/pubmed/7173422

Use of stellate ganglion block for the treatment of psychiatric and behavioral disorders

The present invention is directed to a method for the treatment of a patient suffering from psychiatric and behavioral disorders, including post partum depression, post traumatic stress disorder, compulsive smoking, attention deficit hyperactivity disorder, gambling addiction, comprising the step of administering a stellate ganglion block to the patient to alleviate the symptoms. The stellate ganglion block may be followed by a sympathectomy to provide permanent relief.

United States Patent 20070135871

Kind Code: A1

http://www.freepatentsonline.com/y2007/0135871.html

impairment of the CBF autoregulation after unilateral cervical sympathectomy

Although these findings argued against a neurogenic mechanism, James at al. (1969) reported impairment of autoregulation after unilateral cervical sympathectomy in the babbon. Gotoh et al. (1971/1972) observed impairment of autoregulation in patients with the Shy-Drager syndrome.
It was concluded that the autonomic nervous system plays an important role in the mechanism of autoregulation of CBF and that his mechanism is independent of the chemical control of the cerebral vessels. This was confirmed by direct observation of the pial vessels in cats, where separate sites of action in the vascular tree for autoregulation and chemical control were demonstrated; the autoregulatory reaction was located in pial arteries with a diameter larger than 50 μ, and the reaction to carbon dioxide in pial arteries of smaller diameter (Gotoh et al. 1975).
They concluded that the arteries operating in autoregulation were the larger ones with the dense innervation, while the smaller arteries with sparse innervation were involved in chemical control.
Coronna and Plum (1973) demonstrated the absence of CBF autoregulation in a patient with a Shy-Drager syndrome who had a postganglionic denervation.

Gotoh et al (1979) subsequently showed that autoregulation in patients with this syndrome was impaired irrespective of the localization of the damage to the cervical sympathetic nervous system (preganglionic, central, postganglionic) as judged by the eye instillation test.
Handbook of Clinical Neurology,

Vascular Diseases, Part I by P. J. Vinken, G. W. Bruyn, H. L. Klawans, and J. F. Toole

, Volume 53, Part 1

Elsevier Health Sciences, 1988

hyperhidrosis is not related with social phobia or personality disorder

The total reward dependence and persistence scores were significantly higher in hyperhidrosis patients. The fear of uncertainty in the harm avoidance scale was found to be significantly greater in hyperhidrosis patients. Regarding character dimensions, the total score in each of the subscales self-directedness, cooperativeness and self-transcendence was found to be higher in hyperhidrosis patients.

Conclusion: The higher scores of all subscales of character dimensions in hyperhidrosis patients suggest that hyperhidrosis is not related with social phobia or personality disorder.

http://www.online.karger.com/ProdukteDB/produkte.asp?Aktion=ShowFulltext&ArtikelNr=99589&Ausgabe=232867&ProduktNr=224164

peripheral autonomic denervation affects fear and arousal

States of peripheral autonomic arousal are represented within brain regions that overlap those implicated in emotion Critchley et al. 2000a, Critchley et al. 2000b, Critchley et al. 2001a, Critchley et al. 2001b and Critchley et al. 2001c. Moreover, activity within areas involved in central autonomic control is modulated by feedback of peripheral autonomic responses (Critchley et al., 2001a). These autonomic arousal states bias emotional behavior and influence processes such as memory (e.g., Damasio et al. 1990,Cahill et al. 1994 and Cahill and McGaugh 1998). For example, amygdala is associated with memory enhancement for emotional material, a process thought to be mediated through the influence of states of arousal on amygdalo-hippocampal functional connectivity Cahill et al. 1994, Cahill and McGaugh 1998 and Cahill et al. 1999. Peripheral autonomic arousal may also influence conditioning, as suggested by pharmacological and motivational manipulations in animals Young et al. 1995 and Maren et al. 1994.
http://www.sciencedirect.com/science/article/pii/S0896627302005883

sympathectomy interrupts neural messages to many different organs, glands and muscles

Melatonin production abolished after sympathectomy

Cervical sympathetic nerves may affect blood adrenocorticotropic hormone (ACTH), cortisol (CS), melatonin or serotonin levels. We examined whether stellate ganglion block (SGB), which inhibits this nerve conduction, affects these substances.

During surgery, melatonin circadian rhythm and serotonin levels did not change, but melatonin increased only at night and serotonin decreased after surgery. These findings suggested that some stress stimuli are conducted via cervical sympathetic nerves to the hypothalamus, which is reduced by SGB, and to the pineal gland at night, which causes increased melatonin and decreased serotonin levels.

Authors: Iwama, Hiroshi; Son, Syoraku; Watanabe, Kazuhiro

Source: The Pain Clinic, Volume 13, Number 3, 2001 , pp. 233-244(12)

Publisher: Maney Publishing

Melatonin production abolished after sympathectomy

The amount of 6-sulphatoxymelatonin, the chief metabolite of melatonin, in the urine was measured in nine patients, who were subjected to
bilateral sympathectomy at the second thoracic ganglionic level for treatment of hyperhidrosis of the palms. All patients showed before surgery had a normal 6-sulphatoxymelatonin excretion with a peak in the excretion during the night time. After the sympathectomy, the high night time excretion
was clearly abolished in five patients but remained high in four patients. This indicates that the segmental locations of the preganglionic sympathetic perikarya in the spinal cord, stimulating the melatonin secretion in the pineal gland in humans, vary between individuals.
© 2006 Elsevier Ireland Ltd. All rights reserved.
Molecular and Cellular Endocrinology 252 (2006) 40–45

Melatonin
Melatonin is an important immunomodulator and is the principal means by which tissues are synchronized to the daily cycle of light exposure and physical actity. Cortisol, on the other hand, is critical for maintaining energy homeostasis and modulating immune function. Melatonin and cortisol tend to run opposite to each other.
Deviations from the normal patterns for these hormones can have significant implications for overall health and future risk of cancer. In fact, research shows that low melatonin and high cortisol are independently associated with some of the same health conditions.
Consequently, the balance between these two hormones is important to overall good healt. The melatonin-cortisol index (MCI)s an innovative way of examining the balance between these two vital hormones. The MCI may be used to assess cancer risk and immune function, and may also aid in the assessment of depression, heart disease, osteoporosis and weight management issues.
Melatonin | Rocky Mountain Analytical Lab
http://www.rmalab.com/index.php?id=61

Relationship between sympathovagal tone and personality traits

Results of two-factor ANOVAs revealed substantial differences in personality characteristics depending on the level of sympathetic and parasympathetic tone respectively. Correlational analysis showed remarkable relationships between sympathetic tone and some prominent personality traits. By introducing one of these personality traits (anxiety) as a covariate into two-factor ANCOVAs the originally obtained results were markedly altered.

E. Schweiger, W. Wittling, S. Genzel and A. Block, Department of Physiological and Clinical Psychology, Catholic University of Eichstaett, D-85071, Eichstaett, Germany

Received 27 August 1997. Available online 15 September 1998.

Three months later, fatiguability in the muscles was increased on the sympathecomized sides

We have previously reported functional and histological studies in five beagle dogs with unilateral lumbar sympathectomy. Three months later, fatiguability in the gracilis muscles was increased on the denervated sides, and this was associated with an increase in the relative distribution of FT fibres. Biochemical studies now show that these changes were associated with an increase in cytosolic protein without change in DNA content; this is consistent with an increase in cell size. There was a reduction in the proportion of slow myosin light chain isoforms from 50 7 to 34 6%. Noradrenaline levels were increased on the denervated sides but this may reflect greater vascularity. Calcium content did not correlate with fibre type but there was a positive relation with both noradrenaline content (r = 0.73; P less than 0.05) and DNA content (r = 0.84; P less than 0.05). It is concluded that sympathectomy induces several biochemical changes in skeletal muscle which constitute a change and increase in fast myosin light chain synthesis and a corresponding fibre type transformation.
http://www.ncbi.nlm.nih.gov/pubmed/3359751

Altered response in cutaneous sympathetic outflow to mental and thermal stimuli

NA plasma levels are significantly decreased after sympathectomy for HH

area innervated by the sympathetic T2 and T3 ganglia extends to zones influenced by T1

"doing the same operation through a smaller incision is not necessarily less invasive"

The term ‘‘minimally invasive surgery’’ was initially applied to coelioscopic procedures such as laparoscopic cholecystectomy and hernia repair, thoracoscopic sympathectomy, and arthroscopy, but has since been abandoned, because doing the same operation through a smaller incision is not necessarily less invasive. The term ‘‘minimally invasive parathyroidectomy’’ does not fully convey the nature of the techniques, and, as previously debated in the wider ﬁeld of minimal-access surgery, carries connotations of increased safety that are not necessarily supported by the existing data [12].

Surg Clin N Am 84 (2004) 717–734 F. Fausto Palazzo, MS, FRCS(Gen), Leigh W. Delbridge, MD, FACS* Department of Surgery, Royal North Shore Hospital, Sydney 2065, NSW, Australia

Patients complain of emotional blunting following sympathectomy for hyperhidrosis and blushing

Hohmann, G.W. : The effect of dysfunction of the autonomic nervous system on experienced feelings and emotions

Paper read at Conference on Emotions and Feelings at New School for Social Research, New York, Oct 1962.

Sherrington, C.S.: Experiments on the value of vascular and visceral factors for the genesis of emotion

Proc. Roy.Soc., 1900, 66, 390-403

Wenger, M.A.: Emotion as visceral action: an extension of Lange's theory. In Reymert, M.L., Feelings and emotions: the Moosehart ymposium, New York: McGraw-Hill, 1950. Pp.3-10.

Wynne, L.C., and Solomon, R.L.: Traumatic avoidance learning: acquisition and extinction in dogs deprived of normal peripheral autonomic function.

Genet. psychol. Monogr., 1955, 52, 241-84

Landis, C., and Hunt, W. A. Adrenalin and emotion.

Psychol. Rev., 1932, 39, 467-85.

Schachter, S., and Wheeler, L.: Epinephrine, chlorpromazine, and amusement.

J. of abnorm. soc. Psychol., 1962, 65, 121-28.

Relevant literature

Sherrington, C.S.: Experiments on the value of vascular and visceral factors for the genesis of emotion Proc. Roy.Soc., 1900, 66, 390-403

Wenger, M.A.: Emotion as visceral action: an extension of Lange's theory. In Reymert, M.L., Feelings and emotions: the Moosehart ymposium, New York: McGraw-Hill, 1950. Pp.3-10.

Wynne, L.C., and Solomon, R.L.: Traumatic avoidance learning: acquisition and extinction in dogs deprived of normal peripheral autonomic function. Genet. psychol. Monogr., 1955, 52, 241-84

Landis, C., and Hunt, W. A. Adrenalin and emotion. Psychol. Rev., 1932, 39, 467-85.

Schachter, S., and Wheeler, L.: Epinephrine, chlorpromazine, and amusement. J. of abnorm. soc. Psychol., 1962, 65, 121-28.

Landis, C., and Hunt, W.A.: Adrenalin and emotion. Psychol. Rev., 1932, 39, 467-85.

Sympathectomy results in disturbances in the sympathetic regulation of the peripheral blood flow

Finger skin blood flow was measured in 80 healthy subjects, using laser Doppler imaging during basal vasodilatation at a local temperature of 40 degrees C. The response to cooling of the contralateral hand at 15 degrees C was studied. A vasoconstriction index was calculated in all subjects and a nomogram was constructed, taking age into consideration. Compared with these normal subjects, four patients operated on with transthoracic endoscopic sympathectomy due to hand hyperhidrosis showed clearly attenuated responses. The results indicate that the test can be used to assess disturbances in the sympathetic regulation of the peripheral blood flow.

http://www.ncbi.nlm.nih.gov/pubmed/9568348

decreased conditioning-related activity in insula and amygdala after autonomic denervation

http://www.ncbi.nlm.nih.gov/pubmed/11856537

RESPONSE TO SYMPATHETIC BLOCKADE DEPENDS ON THE DEGREE OF SYMPATHETIC TONE BEFORE THE BLOCK

Denervation of preganglionic cardiac accelerator fibres leaving the cord at T1-T5 results in minimal vasodilatory consequences. Changes however in heart rate, left ventricular function and myocardial oxygen demand may occur due to high thoracic epidural blockade and are discussed below. The major determinant of heart rate is the balance between sympathetic and parasympathetic systems with the latter predominating. A high thoracic epidural anaesthesia (TEA) covering the cardiac segments (T1-T4) produces small but significant reductions in heart rate4-8. During cardiac sympathetic denervation, parasympathetic cardiovascular responses, including those involved in baroreflexes, may dominate. Individual cardiovascular response to different levels of sympathetic blockade varies widely, depending on the degree of sympathetic tone before the block.

Anaesth Intensive Care 2000; 28: 620-635 B. T. VEERING*, M. J. COUSINS† Department of Anesthesiology, Leiden University Medical Center, Leiden, The Netherlands and Department of Anaesthesia and Pain Management, University of Sydney, Royal North Shore Hospital, Sydney, New South Wales

Acquired cardiovascular disease following Sympathectomy

We found statistically significant differences (P < .05) in both time and frequency domains. Parameters that evaluate global cardiac autonomic activity (total power, SD of normal R-R intervals, SD of average normal R-R intervals) and vagal activity (rhythm corresponding to percentage of normal R-R intervals with cycle greater than 50 ms relative to previous interval, square root of mean squared differences of successive normal R-R intervals, high-frequency power, high-frequency power in normalized units) were statistically significantly increased after sympathectomy. Low-frequency power in normalized units, reflecting sympathetic activity, was statistically significantly decreased after sympathectomy. Low-/high-frequency power ratio also showed a significant decrease, indicating relative decrease in sympathetic activity and increase in vagal activity. The Journal of Thoracic and

Cardiovascular Surgery Volume 137, Issue 3, March 2009, Pages 664-669