the PPG signal and the VLF fluctuations of the PPG parameters enable the assessment of the change in sympathetic nervous system activity after sympathectomy

The photoplethysmographic (PPG) signal, which measures cardiac-induced changes in tissue blood volume by light transmission measurements, shows spontaneous fluctuations. In this study, PPG was simultaneously measured in the right and left index fingers of 16 patients undergoing thoracic sympathectomy, and, from each PPG pulse, the amplitude of the pulse (AM) and its maximum (BL) were determined. The parameter AM/BL is proportional to the cardiac-induced blood volume increase, which depends on the arterial wall compliance. AM/BL increased after the thoracic sympathectomy treatment (for male patients, from 2.60±1.49% to 4.81±1.21%), as sympathetic denervation decreases arterial tonus in skin. The very low-frequency (VLF) fluctuations of BL or AM showed high correlation (0.90±0.11 and 0.92±0.07, respectively) between the right and left hands before the thoracic sympathectomy, and a significant decrease in the right-left correlation coefficient (to 0.54±0.22 and 0.76±0.20, respectively) after the operation. The standard deviation of the BL or AM VLF fluctuations also reduced after the treatment, indicating sympathetic mediation of the VLF PPG fluctuations. The study also shows that the analysis of the PPG signal and the VLF fluctuations of the PPG parameters enable the assessment of the change in sympathetic nervous system activity after thoracic sympathectomy.
http://www.springerlink.com/content/w7n21366239753l5/

Depression of Endothelial Nitric Oxide Synthase but Increased Expression of Endothelin-1 Immunoreactivity in Rat Thoracic Aortic Endothelium Associated With Long-term, but Not Short-term Sympathectomy

Circulation Research. 1996;79:317-323

After unilateral sympathectomy the incidence of calcified arteries on the side of operation was significantly higher than that on the contralateral side

Medial arterial calcification is frequently seen in diabetic patients with severe diabetic neuropathy. Sixty patients (19 diabetic and 41 non-diabetic) were examined radiologically for typical Monckeberg's sclerosis of feet arteries 6-8 years after uni- or bilateral lumbar sympathectomy. Fifty-five out of 60 patients (92%) revealed medial calcification. This calcification was observed in both feet of 93% of patients, who had undergone bilateral operation. After unilateral sympathectomy the incidence of calcified arteries on the side of operation was significantly higher than that on the contralateral side (88% versus 18%, p less than 0.01). Although diabetic patients showed longer
stretches of calcification than non-diabetic subjects, the difference was not significant in terms of incidence and length. Of 20 patients who had no evidence of calcinosis pre-operatively, 11 developed medial calcification after unilateral operation exclusively on the side of sympathectomy. In seven patients calcinosis was detected in both feet after bilateral operation. In conclusion, sympathetic denervation is one of the causes of Monckeberg's sclerosis regardless of diabetes mellitus.
PMID: 6873514 [PubMed - indexed for MEDLINE]
Diabetologia. 1983 May;24(5):347-50.

in the media of FAs hypercholesterolemia induces changes similar to those observed in sympathectomized rabbits in non-pathological conditions

In a previous study, we showed that after sympathectomy, the femoral (FA) but not the basilar (BA) artery from non-pathological rabbits manifests migration of adventitial fibroblasts (FBs) into the media and loss of medial smooth muscle cells (SMCs). The aim of the present study was to verify whether similar behaviour of arteries occurred in the pathological context of atherosclerosis.
Our results show that in the media of FAs hypercholesterolemia induces changes similar to those observed in sympathectomized rabbits in non-pathological conditions, i.e., migration of adventitial FBs to the media and loss of medial SMCs. These latter changes, which can be ascribed to pathological events, were accentuated after sympathectomy in the hypercholesterolemic rabbits. The present study reveals that pathological events, including migration and phenotypic modulation of vascular FBs and loss of SMCs, may be under the influence of sympathetic nerves.
Acta Histochemica; Jul2008, Vol. 110 Issue 4, p302-313, 12p

sympathectomy results in an increased collagen content in the vascular wall, suggesting a stiffening of the vessel wall

From animal experiments, it is known that long-term sympathectomy results in an increased collagen content in the vascular wall, suggesting a stiffening of the vessel wall (9). Giannattasio et al.

MEDICINE & SCIENCE IN SPORTS & EXERCISE®
Copyright © 2005 by the American College of Sports Medicine
DOI: 10.1249/01.mss.0000174890.13395.e7

Collagen types I and III mRNA were decreased respectively by 53% and 22% after sympathectomy

In the present study, we tested the hypothesis of the indirect (via the sympathetic nervous system (SNS)) and direct (via AT1 receptors) contributions of Angiotensin II (Ang II) on the synthesis of collagen types I and III in the left ventricle (LV) in vivo. Sympathectomy and blockade of the Ang II receptor AT1 were performed alone or in combination in normotensive rats. The mRNA and protein synthesis of collagen types I and III were examined by Q-RT-PCR and immunoblotting in the LV.

Collagen types I and III mRNA were decreased respectively by 53% and 22% after sympathectomy and only collagen type I mRNA was increased by 52% after AT1 receptor blockade. mRNA was not changed for collagen type I but was decreased by 25% for collagen type III after double treatment. Only collagen protein type III was decreased after sympathectomy by 12%, but collagen proteins were increased respectively for types I and III by 145% and 52% after AT1 receptor blockade and by 45% and 60% after double treatment. Deducted interpretations from our experimental approach suggest that Ang II stimulates indirectly (via SNS) and inhibits directly (via AT1 receptors) the collagen type I at transcriptional and protein levels. For collagen type III, it stimulates indirectly the transcription and inhibited directly the protein level. Therefore, the Ang II regulates collagen synthesis differently through indirect and direct pathways.

http://www.autonomicneuroscience.com/article/S1566-0702(09)00416-0/abstract

we conclude that the sympathetic nervous system influences the metabolic activity of the aorta

The effect of chemical sympathectomy with 6-hydroxydopamine (6-OH-DA) on collagen formation in the aortic wall was investigated in rabbits and rats. Eight weeks after 6-OH-DA treatment of rabbits, there was a significant increase an collagen content in aortas and histologic changes in the elastic elements within the media. The possibility of a direct effect of 6-OH-DA on connective tissue formation was investigated in a subsequent experiment in rats. The rates of collagen synthesis and prolyl hydroxylase activity (PHA) were determined in aortas and in the fibrotic granuloma around subcutaneously implanted polyvinylalcohol sponges. Rates of collagen synthesis and PHA were significantly increased in the aortas of 6-OH-DA treated rats, but not in fibrotic granuloma, confirming the changes seen in the aorta of rabbits and suggesting that 6-OH-DA does not directly affect collagen synthesis. We conclude that the sympathetic nervous system influences the metabolic activity of the aorta. Our data indicate that when the aortic wall is deprived of adrenergic nervous stimulation, changes occur which resemble those seen in natural aging of the aorta. It is plausible to assume that such a metabolic derangement in the vessel wall will make these vessels more vulnerable to additional stresses.

Experimental and Molecular Pathology
Volume 28, Issue 3, June 1978, Pages 279-289

One of the functional consequences of cardiac sympathetic denervation is failure to increase contractility in response to stimuli that depend on endogenous norepinephrine release

One of the functional consequences of cardiac sympathetic denervation is failure to increase contractility in response to stimuli that depend on endogenous norepinephrine release.
www.ncbi.nlm.nih.gov/pubmed/19120145

a significant impairment of the heart rate to workload relationship was consistently observed following sympathectomy

Several reports also demonstrate significantly lower heart rate increases during exercise in subjects who have undergone bilateral ISS [9–12] compared to pre-surgical levels. In spite of this high occurrence, recent reviews on the usual collateral effects of thoracic sympathectomy still do not include these possible cardiac consequences [6].
The aim of the present prospective study was to confirm that a significant impairment of the heart rate to workload relationship was consistently observed following unilateral and/or bilateral surgery.
Eur J Cardiothorac Surg 2001;20:1095-1100
http://ejcts.ctsnetjourna...i/content/full/20/6/1095

slowing of the heart rate usually occurs on the second to fourth day after sympathectomy

The rate fell to a level between 40 and 6o per minute, the maximal slowing usually occurring on the second to fourth day after operation. Consistent slowing of the rate was not observed after a unilateral thoracic sympathectomy of either side. While there was some recovery from the maximum brady-
cardia with the passage of time in most patients, relatively slow resting cardiac rates and failure of tachycardia to develop with postural hypotension or exercise persisted in all patients.



Skoog's12 work has shown that there are marked differences in the number and precise location of the accessory ganglion cells in the cervical region in different patients and on the two sides in the same patient.

Even when a single midthoracic paravertebral ganglion is left in place in an otherwise total sympathectomy the thoracic dermatome supplied by the ganglion appears for several days or weeks to be sympathectomized also. Then, sweating begins to appear, and it increases gradually in amount until the skin of that dermatome may be dripping. This phenomenon more than any other meets the
objection of those who maintain that if residual pathways do exist, the evidence of their presence should be manifest immediately after operation.
Annals of Surgery, 1949 October
Volume 130 Number 4

mechanism of pulmonary edema following sympathectomy

Unilateral pulmonary edema is unusual in presentation and is mainly seen in the re-expansion phase after pneumothorax, systemic-to-pulmonary shunt, parenchymal lung disease, and unilateral sympathectomy. The mechanisms of unilateral pulmonary edema include an increase in capillary blood flow, reduced surfactant, rapid re-expansion of a collapsed lung, and disruption of venular post-capillary sphincter function after sympathectomy.^1–3

http://onlinelibrary.wiley.com/doi/10.1111/j.1527-5299.2005.03861.x/full

bilateral sympathectomy results in marked reduction in concentration of myocardial catecholamines - this affects contractility

Science 10 April 1959: Vol. 129. no. 3354, pp. 967 - 968 DOI: 10.1126/science.129.3354.967 Prev | Table of Contents | Next WOO CHOO LEE 1 and F. E. SHIDEMAN 11 Department of Pharmacology and Toxicology, University of Wisconsin, Madison In cats bilateral sympathectomy or administration of reserpine results in a marked reduction in concentration of myocardial catecholamines. The contractility of papillary muscles from such animals is significantly less than that of muscles from untreated animals. These findings demonstrate the importance of normal levels of myocardial catecholamines in the maintenance of normal cardiac contractility.

abnormal peripheral vascular responses to temperature after sympathectomy

Is Previous Thoracic Sympathectomy a Risk Factor for Exertional Heat Stroke?

Alan D.L. Sihoe, FRCSEd(CTh)^a,_*, Raymond W.T. Liu, MRCP^b, Alex K.L. Lee, MRCP^b, Chak-Wah Lam, FHKAM^b, Lik-Cheung Cheng, FRCS^a
http://ats.ctsnetjournals.org/cgi/content/full/84/3/1025

Post-sympathectomy the peripheral vascular failure or the reduced cardiac chronotropic response can impair the body’s capacity to compensate for shock

First, the abolition of sweating from the upper body as well as the axillae and both upper limbs may have significantly reduced the capacity of the patient to lose heat through sweating during exercise. Anhidrosis in the head and neck after sympathectomy affects a proportion of patients, but is often neglected in most reports of post-sympathectomy complications [3]. The loss of head and neck sweating in this patient may have further impaired overall heat loss. However we would also note that the degree of heat loss impairment after sympathectomy has never been quantified, and its effect on body temperature during exercise remains to be established.
Second, thoracic sympathectomy has been demonstrated to abolish or alter sympathetic vasoconstrictive responses in the skin, and this may contribute to abnormal peripheral vascular responses to temperature [4]
Paradoxically it has been suggested that in some cases there may be abnormal vasoconstriction rather than the expected vasodilatation after sympathectomy [5]. It is not impossible that such atypical peripheral vascular responses to rising body temperature may have contributed to impaired heat loss during exercise or to an inappropriate response to shock on the development of the heat stroke.

In the post-sympathectomy patient, the abnormal sympathetic skin response may lead to peripheral vascular failure or the reduced cardiac chronotropic response may impair the body’s capacity to compensate for shock. These may have contributed to the rapid development of shock and severe multiple organ dysfunction syndrome in this patient.

Third, it has been shown that thoracic sympathectomy can impair the autonomic nervous system’s increase of the heart rate in response to exercise [6]. Although absolute tachycardia is not eliminated, given the endocrine and paracrine stimuli during exercise, the maximum heart rate reached during exercise has been shown to be significantly reduced after sympathectomy. Thus for a given workload during exercise, there will be a relative bradycardia. This may possibly affect the circulatory system’s ability to convey heat from the body core to the extremities for heat loss.

Is Previous Thoracic Sympathectomy a Risk Factor for Exertional Heat Stroke?

Alan D.L. Sihoe, FRCSEd(CTh)^a,_*, Raymond W.T. Liu, MRCP^b, Alex K.L. Lee, MRCP^b, Chak-Wah Lam, FHKAM^b, Lik-Cheung Cheng, FRCS^a
http://ats.ctsnetjournals.org/cgi/content/full/84/3/1025

"Sympathectomy is a technique about which we have limited knowledge, applied to disorders about which we have little understanding."

http://www.pfizer.no/templates/Page____886.aspx

Cardiovascular collapse developing during thoracoscopic thoracic sympathectomy

Cardiovascular collapse developing during thoracoscopic thoracic sympathectomy in a patient with essential palmar hyperhidrosis: A case report.  
Park SJ, Jee DL.

Department of Anesthesiology and Pain Medicine, College of Medicine, Yeungnam University, Daegu, Korea. djee@medical.yeungnam.ac.kr

Thoracoscopic thoracic sympathectomy (TTS) is usually a safe and uncomplicated procedure for treating essential palmar hyperhidrosis. However, we report a case of cardiovascular collapse that developed in a healthy patient undergoing TTS. The surgeon performed the left sympathectomy without incident. However, scarcely had an incision been made in the skin of the right chest when the patient developed sinus bradycardia and sudden, severe hypotension. Pulseless ventricular tachycardia occurred immediately thereafter, which rapidly progressed to ventricular fibrillation and cardiovascular collapse. The patient required resuscitation with 200 J of direct current shock defibrillation along with an intravenous injection of epinephrine 1 mg. She recovered without sequelae. We believe the Bezold-Jarisch reflex was triggered by pooling of venous blood and surgical stimuli, and the patient developed cardiovascular collapse as a result.

Profound Bradycardia in patients having high SDRR:SD sub [partial diffenrential] RR ratios

However, CTS (Chemical Thoracic Sympathectomy) in patients having high SDRR:SD sub [partial diffenrential] RR ratios can result in profound bradycardia.
Anesthesiology. 89(3):666-670, September 1998.
Hirose, Munetaka MD; Imai, Hiroto MD; Ohmori, Misako MD; Matsumoto, Yasunori MD; Amaya, Fumimasa MD; Hosokawa, Toyoshi
MD; Tanaka, Yoshifumi MD

Causes of Syncope:

g) *Syncope via autonomic failure:
i) Neuropathy with autonomic involvement
ii) Antihypertensives, esp. beta-blockers
iii) Surgical sympathectomy
iv) CNS autonomic failure: eg.primary autonomic failure, MSA, spinal cord lesion

Causes of *Collapse and Acute Decreased Conscious State. (* = collapse, as in sudden loss of consciousness). 1. Respiratory (O ...
www.medicine.utas.edu.au/teaching/year6/cam615_616/info/additionaltutes/additionaltutes/med.pdf

Authorised Publication of the School of Medicine
© University of Tasmania ABN 30 764 374 782

baroreflex response as a compensatory function for hemodynamic changes is suppressed in patients who receive ETS

In this study, baroreflex control of HR was completely inhibited in 9 of 21 patients in the depressor test but in only 1 of 19 patients in the pressor test. All patients who showed complete inhibition had received bilateral T2-3 sympathectomy. Responses to decreased blood pressure are mediated by the sympathetic nervous system, whereas responses to increased blood pressure predominantly involve vagal compensation (13). Therefore, it seems that the effects of sympathetic denervation were most prominent in the depressor test after ETS.

The suppression of baroreflex function can be detrimental during anesthetic management. In particular, a poorly preserved baroreflex response to decreasing blood pressure may exaggerate hemodynamic perturbation after a sudden loss of circulating blood volume. In addition, it is possible that patients who have received ETS will show unexpected HR responses after the administration of a vasopressor or vasodilator. We conclude that baroreflex response as a compensatory function for hemodynamic changes is suppressed in patients who receive ETS.
Anesth Analg 2004;98:37-39
http://www.anesthesia-analgesia.org/cgi/content/full/98/1/37

potential complications of hemorrhage, arrythmia, hypotension, pneumothorax, pain, persistent air leak

Thorascopic manipulation of the lung and mediastinal structures may result in cardiac arrhythmias. Electrical current from the cautery may initiate atrial or ventricular tachycardia or fibrillation. Sinus tachycardia may occur secondary to CO2 retention when insufflation techniques are used. A mediastinal shift with compromise of venous return to the heart may initiate a reflex sinus tachycardia. Vagal stimulation and air or CO2 embolism with insufflation techniques may lead to bradycardia or asystole. Hypotension may result from mediastinal tamponade, air or CO2 embolization, or hemorrhage. Hypercarbia, which results from CO2 insufflation, can result in hypertension and tacjycardia. Hemorrhage from the intracostal vessels may occur at the site of trocar placement.
Exposure of the thoracic sympathetic chain requires retraction of the lung apex away from the posterior chest wall. Improper instrumentation and the frequent presence of apical blebs or adhesions may result in a parenchymal lung injury and postoperative pneumothorax or persistent air leak.

The operative procedure and the potential complications of hemorrhage, arrythmia, hypotension, pneumothorax, pain, persistent air leak, inability to complete the procedure thoracoscopically, and death are reviewed with the patient.

Haimovici's Vascular Surgery

Edition: 5, illustrated

Published by Blackwell Publishing, 2004

the heart obeys Starling's law after chemical sympathectomy

This can be seen most dramatically in the case of premature ventricular contraction. The premature ventricular contraction causes early emptying of the left ventricle (LV) into the aorta. Since the next ventricular contraction will come at its regular time, the filling time for the LV increases, causing an increased LV end-diastolic volume. Because of the Frank-Starling law, the next ventricular contraction will be more forceful, causing the ejection of the larger than normal volume of blood, and bringing the LV end-systolic volume back to baseline.

The more the myocardium is dilated, the weaker it can pump, as it then reverts to Laplace's law.
http://en.wikipedia.org/wiki/Frank-Starling_law_of_the_heart

Unilateral and bilateral sympathectomy produced similar reductions in the concentrations of NPY-ir and NA in the ventricular tissue

Differential effects of surgical sympathectomy on rat heart concentrations of neuropeptide Y-immunoreactivity and noradrenaline.

Maccarrone C, Jarrott B.

University of Melbourne, Department of Medicine, Austin Hospital, Heidelberg, Vic., Australia.
J Auton Nerv Syst. 1987 Dec;21(2-3):101-7
The aim of this study was to estimate the proportion of cardiac neuropeptide Y-immunoreactivity (NPY-ir) which is not present in sympathetic neurones innervating the rat heart. The procedure employed was to surgically sympathectomize the heart and then measure the remaining cardiac concentrations of NPY-ir and noradrenaline (NA). Unilateral (left) sympathectomy significantly reduced the levels of NPY-ir and NA in all regions of the heart (by 40-70%) except for the NPY-ir in the right atrium which was unaltered. The effect of bilateral sympathectomy was significantly greater than that of unilateral sympathectomy. Unilateral and bilateral sympathectomy produced similar reductions in the concentrations of NPY-ir and NA in the ventricular tissue. In contrast dissimilar changes were produced in the atrium. Although bilateral sympathectomy almost totally depleted the NA from the right atrium (by 98%), the NPY-ir levels were only reduced by 50%. These results indicate that approximately half the content of NPY in the right atrium is not present in sympathetic noradrenergic neurones. This pool may occur in the previously described intrinsic neurones of the right atrium.
PMID: 3450689 [PubMed - indexed for MEDLINE]

Partial cardiac sympathetic denervation after bilateral thoracic sympathectomy in humans

Partial cardiac sympathetic denervation after bilateral thoracic sympathectomy in humans
Heart Rhythm, Volume 2, Issue 6, Pages 602-609
J.Moak, B.Eldadah, C.Holmes, S.Pechnik, D.Goldstein

All four patients with bilateral sympathectomy had low septal myocardial 6-[¹⁸F]fluorodopamine-derived radioactivity (2,673 ± 92 nCi-kg/cc-mCi at an average of 89 minutes after injection) compared with normal volunteers (3,634 ± 311 nCi-kg/cc-mCi at 83 minutes, N = 22, P = .007) and higher radioactivity than in patients with pure autonomic failure (1,320 ± 300 nCi-kg/cc-mCi at 83 minutes, N = 7, P = .003). Patients with unilateral sympathectomy had normal 6-[¹⁸F]fluorodopamine-derived radioactivity (3,971 ± 337 nCi-kg/cc-mCi at 87 minutes).

Conclusions

Bilateral upper thoracic sympathectomy partly decreases cardiac sympathetic innervation density.

significantly more cholesterol and total lipids in the aorta after sympathectomy

While the vasomotor effect of the sympathetic nervous system (SNS) on the arterial wall is well recognized, its trophic function is not. It is the aim of these studies to demonstrate this all-important function as it relates to the vascular muscle.

Although the exact mechanism by which sympathetic nerve impulses influence the metabolism of the vessel wall is unknown, effects of sympathectomy can be demonstrated. Several lines of evidence indicate that chronic absence of sympathetic innervation in rabbits increases collagen synthesis and decreases activity of tricarboxylic acid cycle enzymes in the vascular wall. When chemically sympathectomized rabbits were fed a 1% cholesterol dietary supplement for 80 days, the aortas of these rabbits contained significantly more cholesterol and total lipids than those from fully innervated controls in spite of insignificant differences in plasma lipids.

In a subsequent series of experiments we analyzed the efficacy of the SNS in two strains of pigeons. White Carneau (WC) pigeons are known by their susceptibility to atherosclerosis of the aorta while Show Racer (SR) pigeons are not. Our results demonstrate that the abdominal aorta of WC pigeons has less sympathetic innervation and it declines faster with age than that of SR pigeons. The results of the described studies documenting the direct trophic influence of the SNS on the arterial wall are reinforced by the similarity to the vessel wall changes induced by partial sympathectomy and natural aging.

Trophic effect of the sympathetic nervous system on vascular smooth muscle

	Annals of Biomedical Engineering
	Springer Netherlands
ISSN	0090-6964 (Print) 1573-9686 (Online)
Issue	Volume 11, Number 6 / November, 1983

Causes of Orthostatic Hypotension

Peripheral

Amyloidosis

Diabetic, alcoholic, or nutritional neuropathy

Familial dysautonomia (Riley-Day syndrome)

Guillain-Barré syndrome

Paraneoplastic syndromes

Pure autonomic failure (formerly called idiopathic orthostatic hypotension)

Surgical sympathectomy

http://www.merckmanuals.com/professional/sec07/ch069/ch069d.html

sympathectomy suppressed the baroreflex control of heart rate during pressor and depressor tests in patients with palmar or axillary hyperhidrosis

We conclude that baroreflex responses are suppressed in patients who receive ETS.

Anesth Analg. 2004 Jan;98(1):37-9, table of contents.Click here to read

PMID: 14693579 [PubMed - indexed for MEDLINE]

interrupting sympathetic efferent fibers innervating the heart and baroreflex

The results suggest that cardiac sympathectomy induced by epidural anesthesia can suppress partially baroreceptor function by interrupting sympathetic efferent fibers innervating the heart during high levels of epidural anesthesia, but that lumbar sympathectomy during epidural anesthesia is unlikely to affect baroreceptor activity.
Baroreflex control of heart rate during cardiac sympathectomy by epidural anesthesia in lightly anesthetized humans.

Dohi S, Tsuchida H, Mayumi T
Anesth Analg 1983; 62:815-20.

Baroreflex sensitivity, measured as cardiac acceleration in response to nitroglycerin, was significantly lower (p < style="font-weight: bold;">The results suggest that baroreflex-mediated response to decreases in arterial pressure is dependent on the integrity of the sympathetic nervous system.

Baroreflex control of heart rate during high thoracic epidural anaesthesia. A randomised clinical trial on anaesthetised humans.
Goertz A, Heinrich H, Seeling W
Anaesthesia 1992; 47:984-7.

Bilateral sympathectomy produced fatal heart block in a few of their experiments

Mendlowitz. Schauer, and Gross⁴ pointed out that the heart rate became slower after removal of the sympathetic chain, but this bradycardia was only temporary. Bilateral sympathectomy produced fatal heart block in a few of their experiments.

American Heart Journal
Volume 22, Issue 4, October 1941, Pages 545-548

bradycardia and other cardiac complications are common side effects?

The most common side effects of sympathectomy are compensatory sweating, gustatory sweating and cardiac changes including decreasing heart rate, systolic-diastolic and mean arterial pressure. The mechanism of bradycardia and other cardiac complications that develop after thoracic sympathectomy are still unclear.

http://tipbilimleri.turkiyeklinikleri.com/abstract_54802.html

Sympathectomy: "suppression of the neuroendocrine stress response"

p.254

Neuraxial blocks typically produce variable decrease in blood pressure that might be accompanied by a decrease in heart rate and cardiac contractility. These effects are generally proportional to the degree (level) of the sympathectomy. Vasomotor tone is primarily determined by sympathetic fibres arising from T5 to L1, innervating arterial and venous smooth muscle. Blocking these nerves causes vasodilation of the venous capacitance vessels, pooling of blood, and decreased vvenous terurn to the heart; in some instances, arterial vasodilation may also decrease systemic vascular resistance. The effects of arterial vasodilation may be minimized by compensatory vasoconstriction above the level of the block. A high sympathetic block not only prevents compensatory vasoconstriction but also blocks the sympathetic cardiac accelerator fibres that arise at T1-T4.
Profound hypotension may result from vasodilation combined with bradycardia and decreased contractility. These effects are further exaggerated if venous return is further compromised by a head-up position or from the weight of a gravid uterus. Unopposed vagal tone in some persons may explain cardiac arrest with spinal anesthesia.
p.261

The sympathetic system normally maintains some tonic vasoconstriction on the vascular tree. Loss off this tone following induction of anesthesia or sympathectomy frequently contributes to perioperative hypotension.
p.375

AV conduction abnormalities are usually manifested by abnormal ventricular depolarization (bundle-branch block) prolongation of the P-R interval (first degree AV block) failure of some atrial impulses to depolarize the ventricles (second degree AV block) or AV dissociation (third degree AV block or complete heart block).
p.428

Clinical anesthesiology By G. Edward Morgan, Maged S. Mikhail, Michael J. Murray
McGraw-Hill, Edition: 3 - 2002

Surgical sympathectomy listed as neurologic disorder

Other neurologic disorders
- Idiopathic orthostatic hypotension
- Multiple sclerosis
- Parkinsonism
- Posterior fossa tumor
- Shy-Drager syndrome
- Spinal cord injury with paraplegia
- Surgical sympathectomy
- Syringomyelia
- Syringobulbia
- Tabes dorsales (syphillis)
- Wernicke's encephalopathy
Dizziness: Classification and Pathophysiology
The Journal of Manual and Manipulative Therapy, Vol. 12, No 4 (2004)

inhibition of sympathetic activity and a possible impairment of endothelial function

Alterations in skin microcirculation induced by brachial plexus block can be evaluated by wavelet transform of the laser Doppler flowmetry signal. Brachial plexus block reduces the oscillatory components within the 0.0095- to 0.021- and 0.021- to 0.052-Hz intervals of the perfusion signal. These alterations are related to inhibition of sympathetic activity and a possible impairment of endothelial function.

Anesthesiology:

September 2006 - Volume 105 - Issue 3 - pp 478-484

Clinical Investigations

Endothelial dysfunction, or the loss of proper endothelial function, is a hallmark for vascular diseases, and often leads to atherosclerosis.
http://en.wikipedia.org/wiki/Endothelium

increased sensitivity to adrenaline is produced by sympathectomy alone

"The increased sensitivity to adrenaline is produced by sympathectomy alone. I think sensory denervation makes no difference."

Vascular Reactivity Following Sympathectomy

Chapter Author: R. T. Grant

Ciba Foundation Symposium - Peripheral Circulation in Man

Book Series: Novartis Foundation Symposia

Published Online: 27 May 2008

Editor(s): G. E. W. Wolstenholme, Jessie S. Freeman

Print ISBN: 9780470714706 Online ISBN: 9780470715185

haemodynamic instability during surgery

Rapid and excessive carbon dioxide insufflation into the closed chest cavity may create a tension pneumopthorax, displace the mediastinum, and compress the lungs and great vessels with consequent haemodynamic instability. During carbon dioxide insufflation using endobronchial intubation, Hartrey and colleagues reported a decrease in systolic arterial pressure of > 20 mm Hg in 21% of patients. Similarly, we have reported sudden hypotension and bradycardia after injudicious carbon dioxide insufflation.

In common with other surgical procedures, routine monitoring during thorascopic sympathectomy should include ECG, pulse oximetry and capnography. However, during thorascopic surgery, SpO2 and end-tidal carbon dioxide have the additional function of monitoring the surgical technique.
BJA 1997;79: 113-119

supersensitivity to sympathomimetic amines in the chronically denervated heart

http://www.ncbi.nlm.nih.gov/pubmed/2988820?dopt=Abstract

bilateral ETS causes the suppression of cardiovascular response to exercise

HR and BP at rest and cardiovascular response to exercise were similar in patients with palmar hyperhidrosis before ETS and in the normal control population. Therefore, we consider that patients with palmar hyperhidrosis have no overactivity of the sympathetic nerve. However, because bilateral ETS causes the suppression of cardiovascular response to exercise, patients that has been treated with ETS need to be observed during high-level exercise.

http://iars.org/abstracts/browsefile/browse.asp?command=N&absnum=45&dir=S190

lead to hyperfunction of the serotoninergic system and pathology

We studied the balance of activity of sympathetic, parasympathetic, and serotoninergic divisions of the autonomic nervous system in the regulation of the heart function in rabbits. High activities of the sympathetic and parasympathetic system are associated with antagonistic interactions between them. Moderation of activity of these systems could be accompanied by activation of the serotoninergic system. Physiological sympathectomy and parasympathectomy lead to hyperfunction of the serotoninergic system and pathology.

Bulletin of Experimental Biology and Medicine, Vol. 140, No. 5, 2005 PHYSIOLOGY

significant decrease of MAP, cardiac arrythmia, cardiac arrest and hypoxemia - complications of ETS surgery

Together, these findings suggest that peripheral sympathetic denervation may modulate immune function via activation of the hypothalamic-pituitary-adrenal (HPA) axis.

Ann N Y Acad Sci. 2000;917:923-34.

Risk of bradycardia after endoscopic electrocautery of the upper thoracic sympathetic ganglia

We evaluated risk of bradycardia after endoscopic electrocautery of the upper thoracic sympathetic ganglia (ETS). Enrolled in this study were 24 patients. Bradycardia, defined as heart rate below 50 beats per min continuing for more than 5 min, was found in 12 patients (50%). All patients were divided into two groups; bradycardia group and non-bradycardia group. Age, sex, region of electrocautery, fentanyl dosage, and operation time were not different between the two groups. Power spectral analysis of heart rate variability revealed that sympathetic activity decreased after ETS. Multivariate analysis indicates that postoperative-minimal heart rate depends upon preoperative heart rate at rest.
http://www.ncbi.nlm.nih.gov/pubmed/10885235

prolongation of the isometric (tension) period (TP) of the left ventricle occurred in the majority (72 per cent) of all cases after sympathectomy

The prolongation of the isometric (tension) period (TP) of the left ventricle which occurred in the majority (72 per cent) of all cases after unilateral or bilateral transthoracic sympathectomy (without or with unilateral or bilateral transthoracic splanchnicotomy) indicates a diminution of inotropic cardiac action. It can be assumed to correspond to the cholinergic (vagal) preponderance which results from a partial or complete sympathetic denervation of the heart. Reduction of the pulse pressure oc-
curred in 56 per cent of the cases, probably due to the same mechanism.

www.chestjournal.org/content/38/4/423.full.pdf
by W RAAB - 1960

blocks the cardiac sympathetic fibers and consequently decreases heart rate, cardiac output and contractility

The CEA (Cervical Epidural Anaesthesia) blocks the cardiac sympathetic fibers and consequently decreases heart rate, cardiac output and contractility. The mean blood pressure is unchanged or decreased, depending on peripheral systemic vascular resistance changes. The baroreflex activity is also partly impaired. Sympathetic blockade also decreases myocardial ischaemia. The cardiovascular changes induced by CEA are also partly due to the systemic effect of the local anaesthetic. The respiratory effects are minimal and depend on the extent of the blockade and the concentration of the local anaesthetic. A moderate restrictive syndrome occurs. Since the phrenic nerves originate from C3 to C5, ventilation may be impaired by CEA. Extension of the block may also impair intercostal muscle function, with a risk of respiratory failure when a CEA is used in patients with compromised respiratory function. The potential specific complications, mainly cardiovascular and respiratory, are the exacerbation of the effects of CEA. Side effects such as bradycardia, hypotension and acute ventilatory failure in relation to respiratory muscle paralysis, may be observed. Close monitoring of haemodynamics, respiratory rate and level blockade is required.
Ann Fr Anesth Reanim. 1993;12(5):483-92.
PMID: 8311355 [PubMed - indexed for MEDLINE

Long-Term Denervation of Vascular Smooth Muscle Causes Not Only Functional but Structural Change

Rosemary D. Bevan, Hiromichi Tsuru

Department of Pharmacology, School of Medicine, University of California, Los Angeles, Calif.

Address of Corresponding Author

Blood Vessels 1979;16:109-112 (DOI: 10.1159/000158197)

sympathectomy leads to peripheral vasodilation, reduced preload, and subsequently decreased cardiac output

Despite a duration of only 2 week, repeated IVRS (intravenous regional sympathetic block) efferent blocks are an attractive alternative to the higher-risk techniques of thoracic sympathetic block and thoracic surgical or thoracoscopic sympathectomy. (p. 848)

Table 42-1
Classification of percutaneous neural destructive procedures:
Anatomy
1. Peripheral neurotomy (such as destruction of intercostal, ilioinguinal nerves)
2. Rhizotomy (spinal dorsal root rhizotomy, trigeminal rhizotomy)
3. Destruction of sensory pathways in the spinal cord (midline punctuate myelotomy, cordotomy)
4. destruction of brain sensory centers (hypophysectomy)
5. Sympathectomy
(p.992)

Cousins and Bridenbaugh's Neural Blockade in Clinical Anesthesia and Pain Medicine by Michael J Cousins, Phillip O Bridenbaugh, Daniel B Carr, and Terese T Horlocker

Wolters Kluwer Health
Edition: 4 - 2008

Acquired cardiovascular disease following Sympathectomy

Effects of endoscopic thoracic sympathectomy for primary hyperhidrosis on cardiac autonomic nervous activity

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

Influence of thoracic sympathectomy on cardiac induced oscillations in tissue blood volume

The parameter AM/BL is proportional to the cardiac-induced blood volume increase, which depends on the arterial wall compliance. AM/BL increased after the thoracic sympathectomy treatment (for male patients, from 2.60 ± 1.49% to 4.81 ± 1.21%), as sympathetic denervation decreases arterial tonus in skin. The very low-frequency (VLF) fluctuations of BL or AM showed high correlation (0.90 ± 0.11 and 0.92 ± 0.07, respectively) between the right and left hands before the thoracic sympathectomy, and a significant decrease in the right-left correlation coefficient (to 0.54 ± 0.22 and 0.76 ± 0.20, respectively) after the operation. The standard deviation of the BL or AM VLF fluctuations also reduced after the treatment, indicating sympathetic mediation of the VLF PPG fluctuations. The study also shows that the analysis of the PPG signal and the VLF fluctuations of the PPG parameters enable the assessment of the change in sympathetic nervous system activity after thoracic sympathectomy.
http://cat.inist.fr/?aModele=afficheN&cpsidt=14106877

sympathectomy will blunt the normal tachycardic response to hypovolemia

Spinal or epidural analgesia may cause a sympathectomy that will blunt the normal tachycardic response to hypovolemia.
OBSTETRIC ANAESTHESIA OUR WAY
Royal Women's Hospital Melbourne
Author: Dr Philip Popham

significant adverse effects on cardiopulmonary physiology

Because of technologic advances and improved postoperative recovery, endoscopic surgery has become the technique of choice for many thoracic surgical procedures^{6 and 25}; however, endoscopic visualization of intrathoracic structures requires retraction or collapse of the ipsilateral lung, which can have significant adverse effects on cardiopulmonary physiology. These cardiopulmonary changes can be further affected by the pathophysiologic changes associated with the disease process requiring the surgical procedure.

Because acute changes in cardiopulmonary function can compromise patient safety severely, a clear understanding of the dynamic interaction between the anesthetic–surgical technique and patient physiology is essential. This article discusses the effect of thoracoscopic surgery and the impact of various anesthetic interventions on cardiovascular and pulmonary physiology. In addition, some recommendations for “damage control” are made.

Anesthesiology Clinics of North America
Volume 19, Issue 1, 1 March 2001, Pages 141-152

Pacemaker after T2 Sympathectomy

A 23-year-old woman with craniofacial hyperhidrosis underwent bilateral thoracoscopic T2-sympathectomy. Marked sinus bradycardia with a mean heart rate of 49 beats/min by Holter ECG monitoring occurred after the procedure and persisted for > 2 years. Normal sinus node function was found by an invasive electrophysiological study and unopposed vagotonia after sympathectomy was diagnosed. A permanent pacemaker was implanted. Although reduced heart rate is a common phenomenon after bilateral dorsal sympathectomy, intractable bradycardia with permanent pacing is rare. This patient demonstrates one of the potential cardiac complications of bilateral sympathectomy.

Pacing and Clinical Electrophysiology

Volume 24 Issue 4 Page 524-525, April 2001

sympathectomy decreased cardiac sympathetic nerve density and norepinephrine level

Cardiac sympathetic innervation was visualized by means of a glyoxylic catecholaminergic histofluorescence method. Transient outward current (I-to) of ventricular myocytes was recorded with the whole-cell configuration of the patch clamp technique. We observed that sympathectomy (i) decreased cardiac sympathetic nerve density and norepinephrine level, (ii) reduced the protein expression of Kv4.2, Kv1.4, and Kv channel-interacting protein 2 (KChIP2), (iii) decreased current densities and delayed activation of I-to channels, (iv) reduced the phosphorylation of extracellular signal-regulated kinase 1 and 2 (ERK1/2) and cAMP response element-binding protein (CREB), and (v) increased the severity of ventricular fibrillation induced by rapid pacing.
Heart Disease Weekly. Atlanta: Dec 28, 2008. pg. 54

Patients may develop bradycardia after surgical procedure

Upper-Thoracic Sympathectomy;
Patients may develop bradycardia after surgical procedure
Heart Disease Weekly. Atlanta: Feb 23, 2003. pg. 71

Cardiac hypertrophy accelerated by left cervical sympathectomy

Cardiac hypertrophy in spontaneously hypertensive rats was accelerated by denervation of the left cervical sympathetic ganglia. Supersensitivity due to denervation may also exist in cardiac muscles.

	Biomedical and Life Sciences
SpringerLink Date	Tuesday, August 02, 2005

Coronary blood flow reduced by 50% after sympathectomy

However, at each level of exercise, mean coronary flow in sympathectomized ventricles was reduced by about 50% compared to control values. The slopes of coronary flow on pressure-rate product and tension-time index were also reduced. No difference in left ventricular oxygen extraction between control and sympathectomized hearts were observed. Thus, chronic ventricular sympathectomy altered the relationships between coronary flow and oxygen consumption, on the one hand, and ventricular oxygen-dependent performance and whole-body exercise level, on the other hand.
Med Sci Sports Exerc. 1988 Apr;20(2):126-35.
http://www.ncbi.nlm.nih.gov/pubmed/3367747

PET Imaging of Oxidative Metabolism Abnormalities in Sympathetically Denervated Myocardium

The average percentage of the left ventricle denervated in the group I animals was 13.1% ±7.3%.
Significant reductions in oxidative metabolism were observed in the sympathectomized tissue both at 2 and 8 wk after surgery (22% and 15% reductions, respectively).

Gary D. Hutchins, Timothy Chen, Kathy A. Carlson, Richard L. Fain, Wendy Winkle, Triad Vavrek, Bruce H. Mock
and Douglas P. Zipes
J NucÃ-Med 1999; 40:846-853

In a person who had a sympathectomy, the sympathetic component of the baroreceptor mechanism is absent

The baroreceptor reflex is only a short-term regulator of blood pressure because the receptors adapt by raising the threshold and lowering discharge rate.
8. Describe the reflex compensations when someone suddenly stands up from a supine position. What would happen in a patient who just had a sympathectomy?

A patient with a sympathectomy would experience what's referred to as orthostatic hypotension (which might lead to syncope). Orthostatic hypotension is a decrease in arterial pressure when going from supine to a standing position. A person with a normal baroreceptor mechanism will try to restore MAP. In a person who had a sympathectomy, the sympathetic component of the baroreceptor mechanism is absent.

Heart Physiology II

M.A.S.T.E.R. Learning Program, UC Davis School of Medicine
Date Revised: Jan 16, 2002
Revised by: Gordon Li and Carolyn Nguyen

Cardiovascular collapse caused by carbon dioxide insufflation during sympathectomy

Carbon dioxide insufflation into the pleural space during one-lung anaesthesia for thoracoscopic surgery is used in some centres to improve surgical access, even though this practice has been associated with well-described cardiovascular compromise. The present report is of a 35-year-old woman undergoing thoracoscopic left dorsal sympathectomy for hyperhidrosis. During one-lung anaesthesia the insufflation of carbon dioxide into the non-ventilated hemithorax for approximately 60 seconds, using a pressure-limited gas inflow, was accompanied by profound bradycardia and hypotension that resolved promptly with the release of the gas.
Australian Society of Anaesthetists 2002

The severity and manifestations of autonomic hyperreflexia are affected by the level of the sympathectomy

With mid-thoracic lesions below the level of cardiac accelerator fibers, hypertension is accompanied by reflex bradycardia transmitted via cardiac accelerator fibers and the vagus. In patients whose sympathectomy is above the level of the thoracic cardiac accelerator fibers, tachycardia may occur because cardiac accelerator fibers become part of the efferent sympathetic activity rather than part of the central inhibitory input from the brain stem and hypothalamus. Arrythmias and occasional heart block may accompany changes in heart rate.
Clinical manifestations of autonomic hyperreflexia include vasodilation, decresed sympathetic activity, and increased vagal activity above the level of the lesion such as nasal congestion, flushing, headache, dyspnea, nausea, and visceral muscle contraction. Vasoconstriction and increased sympathetic activity below the level of the lesion cause vasoconstrictive pallor, sweating, piloerection, and somatic muscle fasciculation. Patients also develop hypertension with headache, blurred vision, myocardial infarction, andretinal, subarachnoid and cerebral hemorrhages that may lead to syncope, convulsion and death.
Handbook of Neuroanesthesia
page 343
By Philippa Newfield, James E. Cottrell

increase in heart rate in response to HUT (head-up tilt) was significantly reduced after surgery

The increase in heart rate in response to HUT (head-up tilt) was significantly reduced after surgery in the ETS group (from 34 ± 18 to 14 ± 11 beats·min⁻¹). Orthostatic hypertension disappeared completely after ETS , whereas the prevalence of orthostatic hypotension increased significantly after ETS (from 3 of 11 to 9 of 11 patients).
http://www.springerlink.com/content/dk8tq89wnhq4naqy/

retarded adaptation of hemodynamics to a sudden start of exercise following sympathectomy

The exercise capacity and the increase of coronary and systemic hemodynamics under treadmill exercise were studied in 5 dogs, chemically sympathectomized with 6-hydroxy-dopamine.

Completeness of adrenergic denervation was verified by stimulation of the right stellate ganglion, by intravenous administration of tyramine, and by demonstration of supersensitivity to exogenous norepinephrine.

These dogs demonstrated a retarded adaptation of hemodynamics to a sudden start of exercise. A fall in mean arterial pressure below 45 mmHg within 10 to 15 sec lead to collapse.
steady state attainment of hemodynamic parameters was considerably delayed.

E. Bassenge¹, J. Holtz¹, W. v. Restorff¹ and K. Oversohl¹

Received: 18 April 1973

Changes in Electrophysiology following sympathectomy

Sympathectomised dogs presented significant increases in: basic sinus period, sino-atrial conduction time (SACT), AH and HV intervals of the His bundle electrogram, atrial functional (AFRP) and effective (AERP) refractory periods, atrio-ventricular node functional (AVNFRP) and effective (AVNERP) refractory periods, ventricular functional (VFRP) and effective (EVRP) refractory periods and atrial (AMAP) and ventricular (VMAP) monophasic action potential durations. Corrected sinus recovery time (CSRT) was not affected by chemical sympathectomy. Neither was the atrial ERP/MAP duration ratio. This new form of sympathectomy affects all the levels of the cardiac conduction system. Such results are in accordance with those obtained with surgical sympathectomy or the use of beta-blocking agents.

DIANE GODIN, CLAUDE GUIMOND, RÉGINALD A NADEAU and A ROBERT LEBLANC

Cardiovascular Research 1982 16(9):524-529;
© 1982 by European Society of Cardiology

Marked Mean Arterial Pressure instability following sympathectomy

all regional hemodynamic changes after sympathectomy and suggest that the sympathetic nervous system may play an important role in reducing short-term hemodynamic variability.
Proceedings of the 7th International Symposium on SHR and Related Studies Held in Lyon (France), Ecole Normale Supérieure, October 28-30, 1991
Genetic Hypertension, by Jean Sassard

Individual cardiovascular response to different levels of sympathetic blockade varies widely, depending on the sympathetic tone

High TEA added to general anaesthesia significantly decreased the cardiac acceleration in response to decreasing blood pressure, suggesting that baroreflex-mediated heart rate response to a decrease in arterial blood pressure depends on the integrity of the sympathetic nervous system.
Anaesthesia and Intensive Care. Edgecliff: Dec 2000. Vol. 28, Iss. 6, p. 620-35 (16 pp.) Australian Society of Anaesthetists

Morphofunctional changes in the myocardium following sympathectomy

Morphofunctional changes in the myocardium following sympathectomy and their role in the development of sudden death from ventricular fibrillation.

Vestn Akad Med Nauk SSSR. 1984;(2):80-5.

Bilateral surgical sympathectomy provides a valuable tool for future investigations of the cellular basis of supersensitivity in the myocardium

Volume 234, Issue 1, pp. 280-287, 07/01/1985
Copyright © 1985 by American Society for Pharmacology and Experimental Therapeutics

After sympathectomy, BP is maintained at nearly normal levels mainly through activation of the renin angiotensin system

Heart and Circulatory Physiology, Vol 259, Issue 5 1337-H1342, Copyright © 1990 by American Physiological Society

The haemodynamic effect of thoracoscopic cardiac sympathectomy

The haemodynamic response to cardiac sympathetic denervation corresponded to the efferent effect of beta-receptor blockade.

Volume 164 Issue S1, Pages 37 - 38, Published Online: 2 Dec 2003

http://www3.interscience.wiley.com/journal/106568649/abstract

Cardiac arrest - a major complication of bilateral sympathectomy

Thoracic sympathectomy has usually minimal consequences if unilateral, especially on the right side. For bilateral procedures, a mean reduction of the heart rate of 12% was reported. Around 50% of patients have bradycardia in the following minutes of a bilateral surgery and mean and diastolic blood pressures significantly reduced.
Since the sympathectomy will block the chronotropic response, a significant increase of the ejection volume is observed when the patient moves in the erect position from dorsal decubitus.
Interact Cardiovasc Thorac Surg. 2008 Nov 27. [Epub

Effect of Endoscopic Transthoracic Sympathicotomy on Heart Rate Variability

Endoscopic transthoracic sympathicotomy is a recently developed technique to reduce pain and ischemia in patients with severe angina pectoris.
ETS caused a shift of sympathovagal balance toward parasympathetic tone.
The American Journal of Cardiology
Volume 79, Issue 11, 1 June 1997, Pages 1447-1452

Cardiac Arrest during Endoscopic Thoracic Sympathicotomy with One Lung Ventilation

Korean J Anesthesiol. 2007 Apr;52(4):479-483.
Published online 2007 April 30. doi: 10.4097/kjae.2007.52.4.479.

Cardiac Arrest during Endoscopic Thoracic Sympathicotomy with One Lung Ventilation under General Anesthesia - Two case reports -

collateral effects of thoracic sympathectomy not disclosed to patients

Several reports also demonstrate significantly lower heart rate increases during exercise in subjects who have undergone bilateral ISS [9–12] compared to pre-surgical levels. In spite of this high occurrence, recent reviews on the usual collateral effects of thoracic sympathectomy still do not include these possible cardiac consequences [6].

Eur J Cardiothorac Surg 2001;20:1095-1100

significant adverse effects on cardiopulmonary physiology

Because of technologic advances and improved postoperative recovery, endoscopic surgery has become the technique of choice for many thoracic surgical procedures^{6 and 25}; however, endoscopic visualization of intrathoracic structures requires retraction or collapse of the ipsilateral lung, which can have significant adverse effects on cardiopulmonary physiology. These cardiopulmonary changes can be further affected by the pathophysiologic changes associated with the disease process requiring the surgical procedure.

Because acute changes in cardiopulmonary function can compromise patient safety severely, a clear understanding of the dynamic interaction between the anesthetic–surgical technique and patient physiology is essential. This article discusses the effect of thoracoscopic surgery and the impact of various anesthetic interventions on cardiovascular and pulmonary physiology. In addition, some recommendations for “damage control” are made.

Anesthesiology Clinics of North America
Volume 19, Issue 1, 1 March 2001, Pages 141-152

low heart rate variability is associated with an increased risk for sudden cardiac death

The amount of short- and long-term variability in heart rate reflects the vagal and sympathetic function of the autonomic nervous system, respectively. Therefore heart rate variability can be used as a monitoring tool in clinical conditions with altered autonomic nervous system function. In postinfarction and diabetic patients, low heart rate variability is associated with an increased risk for sudden cardiac death. A sympathovagal imbalance is also detectable with heart rate variability analysis in coronary artery disease and essential hypertension.
http://www.annals.org/content/118/6/436.abstract

Marked MAP instability following sympathectomy

In conclusion, the results of the present study suggest a major role for the sympathetic nervous system in the regulation of regional circulations, the loss of which in sympathectomized rats results in a marked instability of MAP (mean arterial pressure). The vasodilator component of MAP lability after sympathectomy does not appear to depend on an episodic release of NO synthesized by the L-arginine pathway.

Genetic Hypertension: Proceedings of the 7th International Symposium on SHR and Related Studies Held in Lyon (France), Ecole Normale Supérieure, October 28-30, 1991

By Jean Sassard

BP is maintained at nearly normal levels mainly through activation of the renin angiotensin system

After sympathectomy, BP is maintained at nearly normal levels mainly through activation of the renin angiotensin system.

Heart and Circulatory Physiology, Vol 259, Issue 5 1337-H1342, Copyright © 1990 by American Physiological Society

Electrophysiology - effect on the heart

Sympathectomised dogs presented significant increases in: basic sinus period, sino-atrial conduction time (SACT), AH and HV intervals of the His bundle electrogram, atrial functional (AFRP) and effective(AERP) refractory periods, atrio-ventricular node functional (AVNFRP) and effective (AVNERP) refractory periods, ventricular functional (VFRP) and effective (EVRP) refractory periods and atrial (AMAP) and ventricular (VMAP) monophasic action potential durations. Corrected sinus recovery time (CSRT) was not affected by chemical sympathectomy. Neither was the atrial ERP/MAP duration ratio. This new form of sympathectomy affects all the levels of the cardiac conduction system. Such results are in accordance with those obtained with surgical sympathectomy or the use of beta-blocking agents.

Cardiovascular Research 1982 16(9):524-529; doi:10.1093/cvr/16.9.524

cervical sympathectomy resulted in a rapid degeneration in some of the cells in the sinuatrial and atrioventricular nodes

This study describes the ultrastructural changes in the sinuatrial and atrioventricular nodes of the heart of the monkey (Macaca fascicularis) after right cervical sympathectomy. Obvious changes in the nodal cells were seen one day after operation.Numerous glycogen particles grouped together to form electron-dense patches containing vacuoles in the cytoplasm. At three days after operation, intracellular organelles exhibited fragmentation and dissolution. By five and seven days after operation, the affected cells were vacuolated and some were swollen and appeared to have degenerated. Simultaneously, there was massive infiltration of macrophages were present nodal tissues. Axon profiles and terminals showing various degrees of degeneration were present in the vicinity of the nodal cells throughout the period of study.

J Anat. 1984 October; 139(Pt 3): 449–461.

augmented cholinergic preponderance in cardiac dynamics

In the majority of 16 non-cardiac and in two angina pectoris patients, unilateral
or bilateral endoscopic transthoracic sympathectomy (method of Kux) was followed
by signs of augmented cholinergic preponderance in cardiac dynamics (especially
prolongation of the Isometric period of the left ventricle).

The findings obtained in 16 non-cardiac patients concerning the length
of the isometric or tension period (TP), heart rate and pulse pressure
are represented in Table 1.
In response to transthoracic sympathectomy, all three parameters
varied from person to person in wide ranges in both directions. However,
when the tests were repeated in the same patients at different time inter-
vals after the operation (with or without a second contralateral syrn-
pathectomy inbetween), their qualitative pattern of response (either
upward or downward) remained the same in nearly all instances, as
far as the TP and pulse pressure were concerned. The responses of the
heart rate, on the other hand, were less striking percentage-wise and
varied in quite an irregular fashion in identical individuals.
No significant relationship existed between the magnitude of the pre-
operative average values and the type (positive or negative) or degree
of the postoperative deviations in either one of the three recorded pa-
rameters.

DOI 10.1378/chest.38.4.423
1960;38;423-428
Dis Chest
W. RAAB, E. KUX and H. MARCHET
Effect of Transthoracic Endoscopic Sympathectomy
on the Cardiac Neurovegetative Equilibrium
and on Angina Pectoris

Sympathectomy also results in reduced heart rate variability

"Cardiovascular autonomic neuropathy (CAN) is the most prominent focus because of the life-threatening consequences and the availability of direct tests of cardiovascular autonomic function.. .CAN results from damage due to the autonomic nerve fibers that innervate the heart and blood vessels and results in abnormalities in heart rate control and vascular dynamics. Reduced heart variation is the earliest indicator of CAN."

"CAN is the most studied and clinically important form of DAN. Meta-analyses of published data demonstrate that reduced cardiovascular autonomic function as measured by heart rate variability (HRV) is strongly associated with an increased risk of silent myocardial ischemia and mortality. The determination of the presence of CAN is usually based on a battery of autonomic function tests..."

TECHNICAL REVIEW: Standard of Care - Diabetic Autonomic Neuropathy

Aaron I. Vinik, MD, PHD; Braxton D. Mitchell, PHD
Raelene E. Maser, PHD; Roy Freeman, MD

Reduced Heart Rate Variability associated with incresed mortality

These results support an association between CAN (cardiovascular autonomic neuropathy) and increased risk of mortality. The stronger association observed in studies defining CAN by the presence of two or more abnormalities may be due to more severe autonomic dysfunction in these subjects or a higher frequency of other comorbid complications that contributed to their higher mortality risk. Future studies should evaluate whether early identification of subjects with CAN can lead to a reduction in mortality.

1. Raelene E. Maser, PHD1,
2. Braxton D. Mitchell, PHD2,
3. Aaron I. Vinik, MD, PHD3 and
4. Roy Freeman, MD4

Role of sympathoadrenergic mechanisms in arrhythmogenesis

The NA content in the heart was not measured but it is likely to be small at least at the 10-day period. It is known that three days after chemical sympathectomy NA content is only 7% of normal value [6]. Second, the development of adrenoceptor supersensitivity in the transplanted heart was demonstrated clearly with enhanced heart rate responses to NA or propranolol (at Day 10) [1]. As dennervation sensitization increases the arrhythmia susceptibility [6], it is thus possible that, in the presence of receptor supersensitivity, adrenergic activation occurs by either increase in circulating catecholamines and possibly local release of residual NA, which might still have been sufficient to contribute to arrhythmia development.
Role of sympathoadrenergic mechanisms in arrhythmogenesis
Xiao-Jun Du* and Anthony M. Dart
Baker Medical Research Institute, Melbourne, Victoria, Australia
Cardiovascular Research 1999 43(4):832-834;

Significant reductions in maximal heart rate (HR) and oxygen and carbon dioxide uptakes were observed

Ten patients had positive bronchial challenge test results that remained positive 3 months after surgery, and 2 patients whose challenge test results were negative before surgery became positive after sympathectomy. Significant reductions in maximal heart rate (HR) and oxygen and carbon dioxide uptakes were observed during the maximal exercise test.
CHEST October 2005 vol. 128 no. 4 2702-2705

elevated susceptibility to ventricular fibrillation after sympathectomy

We conclude that chemical sympathectomy downregulates the expression of selective Kv channel subunits and decreases myocardial Ito channel activities, contributing to the elevated susceptibility to ventricular fibrillation.
Canadian Journal of Physiology & Pharmacology; Oct2008, Vol. 86 Issue 10,

response varies depending on the degree of sympathetic tone before the block

Individual cardiovascular response to different levels of sympathetic blockade varies widely, depending on the degree of sympathetic tone before the block.
High TEA added to general anaesthesia significantly decreased the cardiac acceleration in response to decreasing blood pressure, suggesting that baroreflex-mediated heart rate response to a decrease in arterial blood pressure depends on the integrity of the sympathetic nervous system.
Anaesthesia and Intensive Care. Edgecliff: Dec 2000. Vol. 28, Iss. 6, p. 620-35 (16 pp.) Australian Society of Anaesthetists

Bilateral cervical sympathectomies should be avoided because of the destruction of cardioaccelerator tone

http://www.hiesiger.com/physicians/physicianrfl.html

baroreflex response for maintaining cardiovascular stability is suppressed in the patients who received the ETS

Our results indicated that T2-3 sympathectomy suppressed baroreflex control of heart rate
in both pressor and depressor tests in the patients with palmar hyperhidrosis. We should
note that baroreflex response for maintaining cardiovascular stability is suppressed in the
patients who received the ETS.

Anesthesiology 2001; 95:A160

facial anhidrosis and disturbed cardiovascular responses to temperature

"Although thoracic sympathectomy is commonly used to reduce upper limb sweating, it may also lead to facial anhidrosis and disturbed cardiovascular responses to temperature. The resultant effect on overall body heat loss has not been documented. We present a case of a young patient with previous thoracic sympathectomy who suffered severe heat stroke after heavy exercise.
http://ats.ctsnetjournals.org/cgi/content/full/84/3/1025

abnormal peripheral vascular responses to temperature

Thoracic sympathectomy has been demonstrated to abolish or alter sympathetic vasoconstrictive responses in the skin, and this may contribute to abnormal peripheral vascular responses to temperature [4]. Paradoxically it has been suggested that in some cases there may be abnormal vasoconstriction rather than the expected vasodilatation after sympathectomy [5].

It is not impossible that such atypical peripheral vascular responses to rising body temperature may have contributed to impaired heat loss during exercise or to an inappropriate response to shock on the development of the heat stroke.
http://ats.ctsnetjournals.org/cgi/content/full/84/3/1025

more complex autonomic dysfunction than generalised sympathetic overactivity

Cardiac autonomic function in patients (n = 63) with primary focal hyperhidrosis and healthy controls (n = 28) was investigated by short-term frequency domain power spectral analysis of heart rate variability. The power of the very-low-frequency band (0.01-0.05 Hz) was significantly lower in patients with axillary hyperhidrosis than in controls. No differences between groups could be observed at investigation of the low-frequency band (0.05-0.15 Hz), which was a surprising finding because this band represents also sympathetic cardiac innervation. At the high-frequency band (0.15-0.5 Hz), which represents parasympathetic cardiac innervation, an interaction of type and position influencing spectral power was detected. Our highly interesting findings indicate that primary focal hyperhidrosis is based on a much more complex autonomic dysfunction than generalised sympathetic overactivity and seems to involve the parasympathetic nervous system as well.
Eur Neurol 2000;44:112-116 (DOI: 10.1159/000008207)

increased sensitivity to adrenaline is produced by sympathectomy alone

"The increased sensitivity to adrenaline is produced by sympathectomy alone. I think sensory denervation makes no difference."

Vascular Reactivity Following Sympathectomy

Chapter Author: R. T. Grant

Ciba Foundation Symposium - Peripheral Circulation in Man
Book Series: Novartis Foundation Symposia

Published Online: 27 May 2008

Editor(s): G. E. W. Wolstenholme, Jessie S. Freeman

Print ISBN: 9780470714706 Online ISBN: 9780470715185

sympathectomy leads to peripheral vasodilation, reduced preload, and subsequently decreased cardiac output

Despite a duration of only 2 week, repeated IVRS (intravenous regional sympathetic block) efferent blocks are an attractive alternative to the higher-risk techniques of thoracic sympathetic block and thoracic surgical or thoracoscopic sympathectomy. (p. 848)

Table 42-1
Classification of percutaneous neural destructive procedures:
Anatomy
1. Peripheral neurotomy (such as destruction of intercostal, ilioinguinal nerves)
2. Rhizotomy (spinal dorsal root rhizotomy, trigeminal rhizotomy)
3. Destruction of sensory pathways in the spinal cord (midline punctuate myelotomy, cordotomy)
4. destruction of brain sensory centers (hypophysectomy)
5. Sympathectomy
(p.992)
After thoracoscopic sympathectomy for hyperhidrosis, very severe discomfort and hyperhidrosis in the neighboring non-sympathectomized regions occurred with alarming frequency and intensity.
(p.879)

Cardiovascular effects of epidural blockade
"Central" Sympathetic block (T1-T4) - Blockade of
Cardiac sympathetic outflow from vasomotor center
Cardiac sympathetic reflexes at segmental level
Vasoconstrictor fibers to head, neck, and arms

Effect:
HR ↓ CO ↓
Vasodilation in upper limbs
"Inappropriate bradycardia"; "sudden bradycardia"; vagal arrest (p. 247)

↓↓Venous return may result in sudden parasympathetic tone ("faint response")
↓ ↓ HR → cardiac arrest

"Inappropriate" bradycardia (i.e. "normal" HR in face of ↓MAP with sensory level T3-T4)
Peripheral vasodilation should evoke an ↑ HR. But ↓ venous return → ↑vagal tone, so HR remains at preblock rate but is "inappropriately" slow.

↓HR with visceral traction in presence of blockade to T1.
Total sympathetic block
Unopposed vagus
Changes in vagal tone → profound changes in HR; may → transient asystole (p. 248)
Cousins and Bridenbaugh's Neural Blockade in Clinical Anesthesia and Pain Medicine by Michael J Cousins, Phillip O Bridenbaugh, Daniel B Carr, and Terese T Horlocker
Wolters Kluwer Health
Edition: 4 - 2008