Tobias_US_Neuro 17/02/2010 13:17 Page 62
Autonomic Imbalance
Autonomic Nervous System Monitoring of Patients with Excess Parasympathetic
Responses to Sympathetic Challenges—Clinical Observations
Hal Tobias, MD,
1
Alan Vinitsky, MD,
2
Robert J Bulgarelli, DO,
3
Samanwoy Ghosh-Dastidar, PhD
4
and Joe Colombo, PhD
4
1. Neurologist, Private Practice, Stuart, Florida; 2. Primary Care Physician, Private Practice, Gaithersburg, Maryland;
3. Director, Integrative Cardiology, Cardiology Division, Riddle Memorial Hospital; 4. ANSAR Medical Technologies, Inc.
Abstract
A common assumption regarding the autonomic nervous system is that one branch either opposes the other or does not respond during
physiological challenges. Recently, this assumption has been challenged based on clinical observations of unprovoked parasympathetic (P) excess
(PE) during sympathetic (S) stimulation, an abnormal response. Over a three-year period, serial autonomic profiling of 1,340 patients was performed
using the P and S method, which yields independent measures of P and S activity obtained from time–frequency analyses of respiratory activity and
heart rate variability (ANX 3.0, ANSAR Medical Technologies, Inc., Philadelphia, PA). Within this cohort, patients with PE reported symptoms of sleep
difficulties, poor peripheral circulation, general malaise, depression, frequent headache or migraines, gastrointestinal upset, and dizziness when
standing. However, they demonstrated normal heart rate and blood pressure and no other apparent causes for their symptoms. The results of this
study highlight the clinical effects of PE and indicate that, depending on patient history, carvedilol may be effective for patients with cardiovascular
disease (CVD) and low-dose anticholinergics for patients without CVD. In cases where end-organ effects are not yet presented, patients may be
weaned from therapy once PE is resolved.
Keywords
Autonomic nervous system (ANS), parasympathetic, parasympathetic excess/challenge, sympathetic, sympathetic excess/challenge, postural
change, valsalva, beta-adrenergic antagonist, beta-blocker, cardiovascular disease, hypertensive, autonomic imbalance
Disclosure: Samanwoy Ghosh-Dastidar, PhD, is an employee of ANSAR. Joe Colombo, PhD, is an employee and co-owner of ANSAR. The other authors have no conflicts of interest
to declare.
Received: December 3, 2009 Accepted: January 21, 2010
Correspondence: Joe Colombo, PhD, 240 S Eighth Street, Philadelphia, PA 19107. E:
joe@ans-hrv.com
Non-invasive autonomic nervous system (ANS) assessment is often The failure of measures based solely on HRV
2–4
can be attributed to a
based on physiological challenges, such as the Valsalva maneuver and fundamental mathematical conundrum. Basic algebra dictates that a
head-up postural change for the sympathetic nervous system (SNS) and system (e.g. ANS) with two independent components requires two
deep breathing for the parasympathetic nervous system (PSNS). A independent measures to be fully characterized. HRV alone is one
common assumption about the ANS is that the predominant response is such independent measure with multiple dependent measures. A
from stimulation of one ANS branch, and the opposing branch decreases solution to this conundrum was introduced in the 1996 Circulation
its response or does not respond to the challenge. Partially responsible Special Report, standardizing measures based solely on HRV.
1
The
for this assumption is an incomplete understanding of the ANS. solution was validated by the Massachusetts Institute of Technology
(MIT) and Harvard.
5–8
It has recently been implemented for clinical use.
9,10
In the past, measures of autonomic function have been based solely The solution involves the introduction of a second measure of autonomic
on heart rate variability (HRV), which yields mixed assessment of function—respiratory activity (RA). Analyzing RA concurrently with
parasympathetic (P) and sympathetic (S) activity.
1
Therefore, these HRV offers two independent measures of the ANS and thus satisfies
measures cannot provide complete information about the health of the the fundamental algebraic requirement establishing independent,
ANS. Separate tests for S activity and P activity based on these simultaneous measures of P and S activity. Analysis of RA concurrent
measures also yield incomplete information because neither test with HRV is named the ‘P and S method’ in this article.
accounts for the independent actions of the two ANS branches. The
dynamic nature of the ANS and the continuous PSNS and SNS Clinical observations of unprovoked P excess (PE) with P and S measures
interactions dictate the requirement for simultaneous, independent are associated with abnormal clinical and pathophysiological responses.
measures of P and S activity. Only with such measures can the patient’s Chronic conditions such as diabetes,
11–15
thyroid disease,
16
kidney disease,
17
autonomic activities, including responses to disease and common cardiovascular disease (CVD),
11,12
demyelinating and inflammatory
medications, be understood. neurological diseases,
18
certain dementias,
19
depression, and altered
62 © TOUCH BRIEFINGS 2009
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