ACCURACY- Heart Rate Monitors.

[Roger Rittenhouse-vmaxept <roger@vmaxept.com>]

Well I will make this sort of short.. hahah NOT
I have  not been posting much to RC.. BUT after reading a few posts
about this issue.. here it goes.

The use of the HRM on horses has been proven for better then 10 years.
When we first started the V-MAX  - given to us from Tom Ivers- the
accuracy was a major issue BECAUSE many said they were NOT accurate.

I took a system to NEW BOLTON. Put the setup on a horse on a treadmill
along with the standard EKG HR HUMAN machine from HP- like as in $10k
We also put on the current EHRM of the day the old EQB.

The HP showed true HR R to R reading - scope EKG etc. etc.
The EQB did a 20 sec average update
The POLAR based human hrm was about 5 to 8 sec update average.

Horse brought up to trot and fast trot and slow canter.
HP- updates within one sec
EQB very slow HR was close to the HP but about 2 to 5 beats off
POLAR based V-MAX took about 10 seconds to catch up to the HP but once
the HR stabilized -- Reading was +/- ONE (1) beat...

The current flock of HRM systems used on horses use electronics modules
from a number of Human HRM mfgrs.
The MFG. lists the accuracy at +/- 1 bpm.
ALL the current models from used by us  feature a 2 second update.
These readings are projected over a minute.. the more samples you take
the better the reading.. 


The test MUST be taken with the electrodes held fast to the horse.
ERROR comes from MOTION ARTIFACT.. NOISE due to the electrodes sliding
on the surface of the horse skin/hair.
Connection must be WET with a CONDUCTIVE material-- not KY Jelly.

As with the standard method- stethoscope-- one MUST learn how to use the
tool. Many pulse takers do not count correctly nor know what to do with
the half beat. We all know that errors in 15 sec and 30 second can occur
due to mis-counts.
 You are mis-lead IF you think a reading taken by a manual pulse method
for 15 sec is more accurate then reading taking with and electronic
device for 15 30 or 60 sec. 
I never send a horse in unless I have a steady reading for 15 or 30 sec.

A 15 sec count can miss the pulse spikes.

The use of the hand  held device has been proven in many races in the
SE.. I have heard of NO complaints. The pulse takers must learn HOW to
take the pulse - where to place it  and to NOT move it on the horse. The
use of ekg gel is highly recommended to get a good electrical
connection.

A while back a claim was made -the use of these devices were NOT
accurate or reliable. I published a long letter - such as this..
PROVE IT.. 

As one who has more experience with Equine HRM devices then anyone 11
years- except Tom Ivers- I know that they are accurate.
I use one every time my horses go out.
I have never missed a pulse check.. 

I HAVE seen riders go in at 60 taken real quick with a HRM, then bump up
to 64 or 68 and claim the device was in error.. not so -horse was in
trouble - spiking.. 

Case in point- PanAM -- the rider I crewed for trusted the handheld hr
reading - we held the on the line at 60 went in at 54 to 56.

You all do know that you CANNOT wear an analog watch - tic-toc- electric
watch with the HRM rec-- it picks up the pulse from the motor  thus you
read the famous 60 bpm.. i always hear about.

TO make another point-- the Electronic HRMs pick up EKG electrical
signals..not sounds. 
These devices -- the transmitter is triggered by the QRS wave.. Look at
an EKG picture- the down set is the Q  the up swing is the R the down
post fire is the S.... the small waves at the end are the T waves.

The transmitter is set to NOT trigger until the R wave goes about half
way up or almost to the top. The circuit is 'clamped' off to not fire
again on the T wave. Which can be quite high on some subjects.
The transmitter sends and RF- radio freq. - signal to the rec. watch.
The watch counts and stores these pulses. The first reading displayed
may take 5 to 8 second, after that the update is 2 seconds.

IF the transmitter connections are moved - induced electronic noise- the
transmitter may false fire. There are circuits in the transmitter to
filter some of this noise -- but if the transmitter fails to see the R
wave pulse the pulse is dropped.
The rec. circuits sense this and will drop ALL the readings taken during
that sample window.. in this case 2 sec... then start counting again.
The display will show the previous reading for about 4 or 5 samples then
go to 00.
This condition is referred to as 'stuck readings' a MAJOR fault of the
POLAR based systems.. which is why we dropped that line.

The 2 sec window will give the false impression that the 'stuck
readings' due to loose connections - dry connections - improperly placed
electrodes  etc etc.-- since , there will more possibilities during a 2
second sample window that you will get enough good readings.-- less
chances to have artifact in that reading sample.

Another point-- you CANNOT calibrate these units as some have said.. it
is what it is..  you can prove the rec. works - put it along side your
mickey or timex watch and see it reads 60 +/- 1
that concept is pure bunk

You may have seen someone claiming a certain mfg. monitor is FDA
certified accurate for horse or human use  BUNK BUNK LIES FALSE
advertising
CALL the mfg. and ask.. the FDA nor the mfg. of HUMAN hrm don't want to
be associated with each other..
Crap like that really tick me off. Makes the business look bad. Can you
say LAWYER.

So why all this dirge.. well after 11 years I will NOT accept the false
statements that the use human HRM used in equine applications are NOT
accurate.
BUNK unfounded  not proven.. 
ALL studies I have seen from assorted universities claim just the
opposite. They use these devices for major  studies  read like in
Ph.D...

AS with any tool - you must know how to use it... CORRECTLY

Guess I am back in full force.
Had other more FUN issues I was going to talk about
like
PamAm
Doing the TURTLE at GERA
Ride With the STARS
OMNI

Stay tuned
Guess this will start another war-- but get your facts straight and have
the proof.. 

Roger Rittenhouse AERC 8263  SE  
V-MAX
Equine Performance Technology

www.vmaxept.com


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