Some Considerations on the IPFM Model for the Heart Rate
Variability Analysis
O Meste
, G Blain
, S Bermon
University of Nice-Sophia Antipolis, Lab. I3S, France
University of Nice-Sophia Antipolis, Medical school, Lab. of
Physiology, France
Abstract
The arch or inverted arch signals are characterizingpatterns of
the Respiratory Sinus Arrhytmia. The abilityof any model in
generating these patterns can be a goodcriteria for their
selection. We show that using the tidalvolume signal as the input
of the model, an alternative tothe IPFM can be proposed. The
relevance of our model isshown with synthesized and real
signals.
1. Introduction
It is commonly admitted that the IPFM model is apossible model
for the generation of the R waves timeoccurrences . The use of the
outputs s for the frequencyanalysis of the heart rate variability
has been studied indetail in several papers. The latest [1], [2]
gives somerecommendation in using these outputs in order to
reduceor cancel the distortion of the spectrum. The problem ofthe
choice for the model input is not usually addressedand is
simplified using a single or a sum of cosines butnot a real
physiological signal, the respiration for instance.Since the
Respiratory Sinus Arrhytmia (RSA) is one ofthe most important
component of the heart rate variabilityit is straightforward that
effort should be made in takingthe respiration as an input of the
model. In the last CinCwe have proposed [3] a model for the
generation of the Rwaves:
! "
#$#
(1)%'&
(
*),+ -/.021
where 3 is an external modulation. It willbe shown in the
following paper that similarly to the IPFMmodel a time occurrences
generator, called PFM model, canbe deduced from the expression (1).
The condition for thecorrect use of the heart period signal defined
as (4 5 6
7
98
will be also given. The aim of this communicationis to compare
these two models regarding their ability tomimic the RSA when a
real or a synthetic respiration signalis used as the input of the
model.
It has been shown that the repetitive pattern of theRSA can
exhibit different shapes [4] depending on thesubjects and
experimental conditions. These shapes couldbe compared to arch or
inverted arch and will be designatedconsequently. Since this shape
analysis is a step forwardcompared to classical frequency analysis
we will checkwhether the PFM or the IPFM can exhibit these
patternsunder some artificial experimental conditions. We willclose
this communication presenting a real case. Thiscase compares the
outputs obtained from the two models,using the recorded respiration
volume as the input, to themeasured heart period signal from the
real ECG signal.
2. Models definitions and properties
Starting from the R-waves generator defined by (1) andassuming
that the maximum of ) correspond to thetime occurrence of interest
$ , it is clear that the s arethe solution of the equation:
:
;
=>:>@ . The proposed solution of this equationis:
