Angioscan Electronics AngioScan-01, User Manual, Page: 39 / 119

AngioScan Medical Tests 35
© 2014 AngioScan-Electronics LLC
In this example, stress
index and heart rate
variability histogram
are typical for a
healthy person. The
heart rate variability is
due to the effect of the
breathing on the heart
rhythm, which adjusts,
beat-to-beat, to
maintain arterial blood
pressure.
In this example, stress
index is very high and
heart rate variability is
highly limited. Such
test results are
characteristic of
patients with
overactive sympathetic
nervous system, or
with impaired nitric
oxide production, or
with artificial
pacemaker.
Stress index closely correlates with heart rate variability determined by an electrocardiographic Holter
monitor [Wong et al.
2012], during the day as well as in short periods of time (7 hours, 15 minutes)
[Luetal. 2009].
Reduction in heart rate variability is significantly associated with poor prognosis in patients with chronic
heart failure, type 2 diabetes and alcohol heart damage [vanRavenswaaij-Arts et al.
1993]. Heart rate
variability is used to stratify the risk of sudden death in patients with severe cardiac arrhythmias [Task
Force oft he ESC and the NAS of Pacing and Electrophysiology, 1996].
In experimental studies, it has been shown that the stress index was significantly associated with the
level of troponin in patients with acute coronary syndrome [Middleton et al.
2011]. In addition, reducing
the variability of the shape and amplitude of the pulse wave in time is associated with an increased
mortality in patients with acute coronary circulation and acute coronary syndrome [Middleton et al.
2011].
The index values of stress, such as heart rate variability, may have some age variations, without a
significant effect on the overall results of the study.
In patients with pacemakers, especially with the pacemakers that are continuously regulating the
cardiac rhythm, heart rate variability is absent.
In this case, the stress index figures are artificially
inflated.