Altered sympathetic and parasympathetic activity in lung transplantation patients at rest and following autonomic perturbation.
OBJECTIVE
To investigate the nature and extent of the alteration in autonomic function following heterotopic lung transplantation.


METHODS
Measures of cardiac parasympathetic nervous system activity (PNSA) and systemic sympathetic nervous system activity (SNSA) were compared in lung transplant patients and age-matched healthy subjects, both at rest and following autonomic perturbation.


METHODS
Lung transplantation service of a university teaching hospital.


METHODS
Twenty-two lung transplant patients (mean [+/- SEM] age, 50.5 +/- 2.4 years) and 13 healthy subjects (mean age, 48.2 +/- 3.7 years).


RESULTS
Lung transplant patients had decreased baseline time and frequency domain measures of heart rate variability compared to healthy subjects (root mean square of successive differences in R-R intervals, 11.2 +/- 1.1 vs 30.3 +/- 4.5 ms, respectively [p < 0.005]; LnHP, 2.4 +/- 0.2 vs 4.8 +/- 0.4 ms(2), respectively [p < 0.005]). In addition, lung transplant patients demonstrated an attenuated reduction in LnHP/LnTP following head-up tilt in comparison to healthy subjects (p < 0.05). The baseline recumbent plasma norepinephrine level was increased in lung transplant patients compared to healthy subjects (3.25 +/- 0.43 vs 2.00 +/- 0.27 nmol/L, respectively; p < 0.05), and levels increased in both groups with upright head-up tilt. There were no differences between the two groups in heart rate or mean systolic BP responses to both the Valsalva maneuver and cold pressor testing.


CONCLUSIONS
Lung transplant patients have both reduced PNSA and increased SNSA at rest. Furthermore, these patients appear to have a preserved capacity to respond to autonomic perturbation by increasing SNSA. The mechanisms underlying these observations and their prognostic implications remain to be determined.
Berakis
Amy
A
Clinical Pharmacology Unit, Department of Epidemiology and Preventive Medicine, Monash University Medical School, Alfred Hospital, Prahran, Victoria 3181, Australia.
Williams
Trevor J
TJ
Naughton
Mathew T
MT
Martin
Jennifer H
JH
Muhlmann
Michael
M
Krum
Henry
H
D000328:Adult; D000704:Analysis of Variance; D001510:Bed Rest; D001795:Blood Pressure Determination; D016022:Case-Control Studies; D002395:Catecholamines / Q000097:blood; D015331:Cohort Studies; D003080:Cold Temperature; D005260:Female; D006339:Heart Rate / Q000502:physiology; D006801:Humans; D008168:Lung / Q000294:innervation*; D016040:Lung Transplantation; D008297:Male; D008875:Middle Aged; D010275:Parasympathetic Nervous System / Q000502:physiology*; D011311:Pressoreceptors / Q000502:physiology; D011336:Probability; D012016:Reference Values; D012680:Sensitivity and Specificity; D013564:Sympathetic Nervous System / Q000502:physiology*; D014636:Valsalva Maneuver
D002395:Catecholamines