DIY Heart ECG wearable recorder (Holter monitor)

[Kaptein QK]

Experiencing strange sensations and feelings in my chest I did the only logical thing... Make a ECG recorder! 

I bought a front end from http://www.100randomtasks.com/ecg-front-end
and connected it to an Arduino Nano. (Don't worry, no Arduino IDE's where harmed in this project...)

The data is stored in a 16MB flash chip.

The PC part where written in C#, my first program in that newfangled thing called OOP.

See pictures and ZIP file for source code. If there is interest I can provide more details.

I was able to catch a few of those glitches, see picture. (Third line in the middle)

Now tell me...   How much time do I have?   

[mmagin]

While this kind of configuration seems to work fine for the simple heart-rate monitors used when people are working out, I seem to recall that most ECG setups (even simple ones) use some kind of driven guard electrode attached elsewhere on the torso.

[Kaptein QK]

While this kind of configuration seems to work fine for the simple heart-rate monitors used when people are working out, I seem to recall that most ECG setups (even simple ones) use some kind of driven guard electrode attached elsewhere on the torso.

The ECG front end has resistors from each lead to Vref to keep the common input voltage in range for the input amplifier.

[Kaptein QK]

Now tell me...   How much time do I have?

Looking at the ECG waveform I'd say 15 months, at most!

Hey, that is not to bad, I get to see another summer! 

[saturation]

That strange 'blip' above the red line is a premature ventricular contraction. 

http://en.wikipedia.org/wiki/Premature_ventricular_contraction

[mmagin]

While this kind of configuration seems to work fine for the simple heart-rate monitors used when people are working out, I seem to recall that most ECG setups (even simple ones) use some kind of driven guard electrode attached elsewhere on the torso.

The ECG front end has resistors from each lead to Vref to keep the common input voltage in range for the input amplifier.

That might be enough, I'm not experienced enough to be sure -- I was thinking the movement of the leads and amplifier relative to the patient could cause enough interference in the signal to be a problem, maybe.  I've only done this once long ago in a college class with an instrumentation amplifier and a commercial A/D board.  I think we had a third electrode on the torso which was driven by the amplifier output or something.  Possibly this was more essential when the amplifier wasn't mounted right on the subject

[Chryseus]

I see nothing wrong besides a PAC followed by a PVC on the second line which is nothing to be concerned about, first and third line is due to noise from movement or the leads making poor connection.

[Psi]

You should put a bright LED matrix on the box, so at night you actually see your realtime ECG waveform through your tshirt

hehe, electrolumenesent array t-shirt that shows realtime ECG
Now that's a good idea for a kickstarter.

Actually i think a flex PCB with bright SMT leds would be better. Best to make it not part of the tshirt at all.
Just have a internal pocket behind the chest where the flex board sits.

[Psi]

Id like to see your doctors face when you show up with your own home built ECG readout of the issue.

[Kaptein QK]

That strange 'blip' above the red line is a premature ventricular contraction. 

http://en.wikipedia.org/wiki/Premature_ventricular_contraction

Thanks!

[Kaptein QK]

I see nothing wrong besides a PAC followed by a PVC on the second line which is nothing to be concerned about, first and third line is due to noise from movement or the leads making poor connection.

Thanks!  The noise is due to movement.
The incident which made me make this device was much longer (minutes), but I did not have other symptoms. It only happened a few times during a hour.
So I guess I will see several summers come and go!

[Kaptein QK]

You should put a bright LED matrix on the box, so at night you actually see your realtime ECG waveform through your tshirt

hehe, electrolumenesent array t-shirt that shows realtime ECG
Now that's a good idea for a kickstarter.

Actually i think a flex PCB with bright SMT leds would be better. Best to make it not part of the tshirt at all.
Just have a internal pocket behind the chest where the flex board sits.

Haha, good idea! Imagine a date: "Your BPM is rising. Are you getting horny?"   

[Kaptein QK]

Id like to see your doctors face when you show up with your own home built ECG readout of the issue.

Unfortunately I do not have recording of the issue which made me make this device. Since there where no other symptoms I will let the doctor wait.   

[Psi]

You have the screen capture of it.