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;
"Sympathectomy is a technique about which we have limited knowledge, applied to disorders about which we have little understanding." Associate Professor Robert Boas, Faculty of Pain Medicine of the Australasian College of Anaesthetists and the Royal College of Anaesthetists, The Journal of Pain, Vol 1, No 4 (Winter), 2000: pp 258-260
The amount of compensatory sweating depends on the patient, the damage that the white rami communicans incurs, and the amount of cell body reorganization in the spinal cord after surgery.
Other potential complications include inadequate resection of the ganglia, gustatory sweating, pneumothorax, cardiac dysfunction, post-operative pain, and finally Horner’s syndrome secondary to resection of the stellate ganglion.
www.ubcmj.com/pdf/ubcmj_2_1_2010_24-29.pdf
After severing the cervical sympathetic trunk, the cells of the cervical sympathetic ganglion undergo transneuronic degeneration
After severing the sympathetic trunk, the cells of its origin undergo complete disintegration within a year.
http://onlinelibrary.wiley.com/doi/10.1111/j.1439-0442.1967.tb00255.x/abstract
Other potential complications include inadequate resection of the ganglia, gustatory sweating, pneumothorax, cardiac dysfunction, post-operative pain, and finally Horner’s syndrome secondary to resection of the stellate ganglion.
www.ubcmj.com/pdf/ubcmj_2_1_2010_24-29.pdf
After severing the cervical sympathetic trunk, the cells of the cervical sympathetic ganglion undergo transneuronic degeneration
After severing the sympathetic trunk, the cells of its origin undergo complete disintegration within a year.
http://onlinelibrary.wiley.com/doi/10.1111/j.1439-0442.1967.tb00255.x/abstract
Tuesday, June 28, 2011
Monday, June 27, 2011
Sympathectomy altered electroactivity on the heart
The influences on the cardiac autonomic nerve system of the ETS of upper thoracic sympathetic nerve were seen to be of a lesser degree at rest. However, the response to sympathetic stimulation was suppressed after the surgery.
Eur J Cardiothorac Surg 1999;15:194-198
http://ejcts.ctsnetjournals.org/cgi/content/full/15/2/194
Sunday, June 26, 2011
reduced high-frequency power after sympathetic blockade
Alternatively, reduced high-frequency power after sympathetic blockade may also be explained by diminished “accentuated antagonism,” a phenomenon described more than three decades ago (4). Heart rate response to vagal nerve stimulation is accentuated when sympathetic tone is elevated, and vice versa. Thus, cardiac sympathetic withdrawal by high spinal or epidural blockade may have resulted in diminished beat-to-beat fluctuations of R-R intervals without alteration of actual vagal nerve activity. To draw a definitive conclusion regarding the mechanism, determinations of central vagal/sympathetic outflow would be mandatory by an animal experiment.
http://www.anesthesia-analgesia.org/content/100/4/1216.2.full
http://www.anesthesia-analgesia.org/content/100/4/1216.2.full
- 1.↵ Tanaka M, Goyagi T, Kimura T, Nishikawa T. The effects of cervical and lumbar epidural anesthesia on heart rate variability and spontaneous sequence baroreflex sensitivity. Anesth Analg 2004;99:924–9.
- 2.↵ Introna R, Yodlowski E, Pruett J, et al. Sympathovagal effects of spinal anesthesia assessed by heart rate variability analysis. Anesth Analg 1995;80:315–21.
- 3.↵ Malliani A, Pagani M, Lombardi F, et al. Cardiovascular regulation explored in the frequency domain. Circulation 1991;84:482–92.
- 4.↵ Levy MN. Sympathetic-parasympathetic interactions in the heart. Circ Res1971;29:437–45.
Saturday, June 4, 2011
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/
http://www.springerlink.com/content/w7n21366239753l5/
Thursday, June 2, 2011
sympathectomy leads to qualitative alterations in localized bone modeling and remodeling
Bone modeling and remodeling are highly regulated processes in the mammalian skeleton. The exact mechanism by which bone can be modeled at a local site with little or no effect at adjacent anatomic sites is unknown. Disruption of the control of modeling within the temporal bone may lead to various bone disease such as otosclerosis, osteogenesis imperfecta, Paget's disease of bone, fibrous dysplasia, or the erosion of bone associated with chronic otitis media. One possible mechanism for such delicate control may be related to the ubiquitous and rich sympathetic innervation of all periosteal surfaces. Previous studies have indicated that regional sympathectomy leads to qualitative alterations in localized bone modeling and remodeling. In this study, unilateral cervical sympathectomy resulted in significant increases in osteoclast surface and osteoclast number within the ipsilateral bulla of experimental animals. The mechanisms by which sympathectomy leads to increased local bone loss is unknown. Potential mechanisms include disinhibition of resorption, secondary to the elimination of periosteal sympathetics, as well as indirect vascular effects.
http://www.ncbi.nlm.nih.gov/pubmed/8723974
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