The Science Behind the Pulse Wave Profiler

The PWP measures the variations in heart rate of a patient in a resting state. Under resting conditions, the ECG of healthy individuals exhibits periodic variation in the interbeat intervals.

  • Many clinicians view the heart as a periodic oscillator whose rate varies according to the demands of the organism. However, there is growing evidence that under physiologic conditions, the heart is not a periodic oscillator. (1-5)
  • Variability in heart rate reflects the vagal and sympathetic function of the autonomic nervous system, and has been used as a monitoring tool in clinical conditions characterized by altered autonomic nervous system function (6) Spectral analysis of beat-to-beat variability is a simple, noninvasive technique to evaluate autonomic dysfunction. (7)
  • Heart rate variability analysis has been used in the assessment of diabetic neuropathy and to predict the risk of arrhythmic events following myocardial infarction. (9) The technique has also been used to investigate autonomic changes associated with neurotoxicity (10), physical exercise (10) anorexia nervosa, (10) brain infarction (11), angina (12), and panic disorder (13).
  • Normative data on heart rate variability have been collected (14,15,16). This technology appears to hold promise for assessing overall fitness. Gallagher et al (17) compared age-matched groups with different lifestyles. These were smokers, sedentary persons, and aerobically fit individuals. They found that smoking and a sedentary lifestyle reduces vagal tone, whereas enhanced aerobic fitness increases vagal tone. Dixon et al (18) reported that endurance training modifies heart rate control through neurocardiac mechanisms. In occupational health, the effects of various stresses of the work environment of heart patients and asymptomatic workers may be evaluated using heart rate variability analysis (19).

Heart Rate Variability and Vertebral Subluxation

Zhang and Dean (20) reported the results of a study involving 520 subjects in a single-visit group, and 111 subjects in a four-week group. The purpose of the study was to investigate the effect of chiropractic care in a multi-clinic setting on the balance of the sympathetic and parasympathetic nervous system using HRV analysis. The study demonstrated consistent changes in HRV. The authors reported, “The decreased heart rate and increased total power from the HRV analysis indicated a healthy autonomic nervous system balance after correction of vertebral subluxation.”

What information is Gathered During the PWP Scan?

The Instantaneous Heart Rate (IHR) – This view shows the actual heart rate over the entire data collection period. As you can see from this graph, the average heart rate over this period is around 67, but the actual values range from less than 55 to over 85 – this variability is exactly what we are measuring with this protocol. The blue line at the bottom indicates the SCR (Skin Conductance Response) values. In this scan, the SCR remains under the black line (threshold), indicating that there was no unexpected “spike” in nervous system arousal.

Frequency Domain Analysis – This view is very useful for client education and for interpreting the results of the HRV analysis. It shows parasympathetic vs. sympathetic response in the autonomic nervous system. In a balanced system both branches of the ANS are in the normal range, as shown by the location of the green square in the center box. The section in which the square appears indicates whether the system is balanced or whether one response is dominant for a particular client.

Table and Narrative Views – The Table and Narrative views provide statistical analysis from the scan. The narrative also describes the protocol in detail, and provides several literature references.

References

  1. 1. Kent C: “Models of vertebral subluxation: a review.” Journal of Vertebral Subluxation Research 1996;1(1):11.
  2. 2. Boone WR, Dobson GJ: “A proposed vertebral subluxation model reflecting traditional concepts and recent advances in health and science.” Journal of Vertebral Subluxation Research 1996;1(1):19.
  3. 3. Epstein D: “Network Spinal Analysis: a system of health care delivery within the subluxation-based chiropractic model.” Journal of Vertebral Subluxation Research 1996;1(1):51.
  4. 4. Kale MU, Keeter T: “A mechanical analysis of the side posture and knee-chest specific adjustment techniques.” Journal of Vertebral Subluxation Research 1996;1(3):35.
  5. 5. Morter Jr T: “The theoretical basis and rationale for the clinical application of bio-energetic synchronization.” Journal of Vertebral Subluxation Research 1996;2(1):23.
  6. 6. Schwartzbauer J, Kolber J, Swartzbauer M, et al: “Athletic performance and physiological measures in baseball players following upper cervical chiropractic care: a pilot study.” Journal of Vertebral Subluxation Research 1996;1(4):33.
  7. 7. Kessinger R: “Changes in pulmonary function associated with upper cervical specific chiropractic care.” Journal of Vertebral Subluxation Research 1996;1(3):43.
  8. 8. Graham RL, Pistolese RA: “An impairment rating analysis of asthmatic children under chiropractic care.” Journal of Vertebral Subluxation Research 1996;1(4):41.
  9. 9. Kessinger R, Boneva D: “Changes in visual acuity in patients receiving upper cervical specific chiropractic care.” Journal of Vertebral Subluxation Research 1996;2(1):43.
  10. 10. Blanks RH, Schuster TL, Dobson M: “A retrospective assessment of Network care using a survey of self-rated health, wellness, and quality of life.” Journal of Vertebral Subluxation Research 1996;1(4):15.
  11. 11. Kent C: “Surface electromyography in the assessment of changes in paraspinal muscle activity associated with vertebral subluxation: a review.” Journal of Vertebral Subluxation Research 1996;1(3):97.
  12. 12. Gentempo P, Kent C, Hightower B, Minicozzi SJ: “Normative data for paraspinal surface electromyographic scanning using a 25-500 Hz bandpass.” Journal of Vertebral Subluxation Research 1996;1(1):43.
  13. 13. Shaikewitz M: “A demographic and physical characterization of cervical spine curvature and degeneration.” Journal of Vertebral Subluxation Research 1996;1(2):41.
  14. 14. Kent C, Rondberg T, Dobson M: “A survey response regarding the appropriateness of professional practice guidelines to subluxation- based chiropractic.” Journal of Vertebral Subluxation Research 1996;1(2):13.
  15. 15. McCoy HG, McCoy M: “A multiple parameter assessment of whiplash injury patients undergoing subluxation-based chiropractic care: a retrospective study.” Journal of Vertebral Subluxation Research 1996;1(3):51.
  16. 16. Cover and page 3. Journal of Vertebral Subluxation Research 1996;2(1).
  17. 17. Evans JM: “Differential compliance measured by the function recording and analysis system in the assessment of vertebral subluxation.” Journal of Vertebral Subluxation Research 1996;2(1):15.
  18. 18. Pistolese RA: “Risk assessment of neurological and/or vertebrobasilar complications in the pediatric chiropractic patient.” Journal of Vertebral Subluxation Research 1996;2(2):77.
  19. 19. Vanquaethem PL, Gould JL: “The use of a numerical point system in the assessment of clinical progress in patients under subluxation- based chiropractic care: a case study.” Journal of Vertebral Subluxation Research 1996;2(2):97.