David-
Your friend should ask his/her doctor about ordering a cardiac event  
recorder.  Basically what happens is that the patient wears a device  
which is constantly capturing and saving the last few minutes of an  
EKG tracing.  He/she pushes a button whenever the abnormal heartbeat  
or whatever occurs.    After pushing the button the patient is  
instructed to call a monitoring service and downloads over the phone  
the last 15 or so minutes of heart beats prior to the button push.   
Typically, the patient wears the device for 2-4 weeks which is usually  
enough to get the needed information.  It is usually a very helpful  
test.

For true diagnostic purposes you really need to capture an EKG signal  
and save that.  An R-R interval recording device may confirm the  
presence of an arrhythmia but still leave the exact diagnosis in  
question.  The absence of any abnormal rhythm during or preceding the  
symptoms would lead one away from a cardiac diagnosis.

Dave

On Nov 5, 2009, at 3:13 PM, David Duffy (AVD) wrote:

> Apptech wrote:
>>> Has anyone here built a heart beat logger? I'm wanting to log each  
>>> beat,
>>> not the average rate.
>>>
>>> It would be worn by the user while sleeping. Wireless would be  
>>> ideal,
>>> but tethered is not out of the question.
>>>
>>
>> For interest - what is the reason?
>>
>
> Hi Russell,
> Someone I know has an ongoing issue (last few years) of an occasional
> feeling of racing heart, accompanied by feeling "odd / shaky" at that
> moment. Almost always while sleeping (it wakes them up), but it has
> occurred while awake a few times.
>
> They have tried wearing a 24 hour heart monitor (on loan from  
> hospital),
> but Murphy's Law has always meant that the symptom has never occurred
> when the monitor was present.
>
> In a given month, the effect may happen 0 - 8 times, seemingly with no
> pattern. Various doctors and specialists are yet to figure out what is
> going on.
>
> Since the episodes are fairly brief and hard to capture, there is
> uncertainty on whether the heart is doing weird stuff, or it just  
> feels
> that way.
>
> The logger idea was to try to record heart beat data over extended
> periods for review if an episode had occurred. Hopefully this data may
> help doctors get further down the path to a solution.
> David...
>
> -- 
> ___________________________________________
> David Duffy        Audio Visual Devices P/L
> Unit 8, 10 Hook St, Capalaba 4157 Australia
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