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"A
Retrospective Evaluation of Acupuncture Outcomes as a
Function of Heart Rate Variability"
Abstract of Poster Presentation for Society of
Acupuncture Research Meeting October, 2004.
Kristen T. Sparrow, M.D.
(Society for Acupuncture Research Abstract 2004 Symposium)
It has been postulated that acupuncture affects the
cardiovascular system through the autonomic nervous
system. Using power spectral analysis, the ratio of low
frequency to high frequency components of heart rate
variability can be calculated. This ratio reflects
relative input from sympathetic and parasympathetic
aspects of the autonomic nervous system. Heart rate
variability monitoring is a simple, non-invasive method
which can be used in a clinical setting. In this study I
evaluated Heart rate Variability and some other
physiological data retrospectively to see if any patterns
developed that could shed light on the autonomic processes
occurring during acupuncture treatment.
Patients were randomly selected for monitoring. Patients
were diagnosed and treated in accordance with Traditional
Chinese Medicine. They were referred or self-referred with
an established allopathic medical diagnosis. Physiological
monitors (J and J engineering Biofeedback Monitor) were
placed. After a 10 minute equilibration period, monitoring
was begun, needles were placed. Needles were removed after
25 minutes. There were 17 patients who qualified for
inclusion in the data collection analysis. Data was
collected including, heart rate, the inter-beat interval,
Very low frequency, Low frequency, and High the frequency
heart rate variability spectra, total power, peripheral
temperature, and skin resistance. According to Malik, the
ratio of Low Frequency spectrum to the High frequency
spectrum can be used as an estimate of sympathovagal
balance. This ratio was calculated in all patients and
charted, a moving average was applied to simplify
comparison. All data analysis was done retrospectively,
i.e. the data collection and values in no way influenced
treatment.
When the LFR/HFR ratio was evaluated, there appeared to be
a correlation between success in treatment, as judged by
the patient and a decrease in their LFR/HFR ratio during
treatment (intra-treatment) 62% of the time. In general,
patients who were NOT HELPED by the acupuncture treatment
series, or where it was equivocal (4 out of 17 patients),
showed little decrease in LFR/HFR. On the contrary there
was an overall increase in their LFR/HFR ratio
intra-treatment 19% of the time. No inter-treatment trends
were identified in either group. In addition, there were
two phenomena that occurred with some regularity. The
first was on many occasions the LFR/HFR ratio increased
after needle placement and in the following 7-8 minutes,
and then decreased back to baseline or below it. It also
occurred, not infrequently, that the LFR/HFR ratio would
start to increase abruptly after approximately 20 minutes
of treatment.
Though this was not a rigorous scientific study and
qualifies more as a pilot exploration, it does raise some
interesting questions concerning the autonomic nervous
system response, stress and disease, and possibilities for
further studies, which will be discussed.
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