Print this Post

DIY ECG Detected an Irregular Heartbeat


I have simplified and improved my ECG machine design! Check out the new post:


Am I going to die? It’s unlikely. Upon analyzing ~20 minutes of heartbeat data (some of which is depicted in the previous entry) I found a peculiarity. Technically this could be some kind of noise (a ‘pop’ in the microphone signal due to the shuffling of wires or a momentary disconnect from the electrodes or perhaps even a static shock to my body from something), but because this peculiarity happened only once in 20 minutes I’m not ruling out the possibility that this is the first irregular heartbeat I captured with my DIY ECG. Note that single-beat irregularities are common, and that this does not alarm me so much as fascinates me. Below is the section of the data which contains this irregular beat.

In the spirit of improvement I wonder how much more interesting this project would be if I were to combine the already-designed ECG machine with a sensor to detect the physical effect of the heart’s beating on my vasculature. in other words, can I combine my electrical traces with physical traces? (Blood pressure or blood flow) I found an interesting site that shows how someone built a DIY blood flow meter using a piezo film pulse sensor. Pretty clever I must say… but I think I draw my limit at what I’ve done. Although blood flow would be interesting to analyze (does the murmur depicted above produce an alteration in normal blood flow?), it’s not worth the time, hassle or expense of building.

About the author

Scott W Harden

Scott Harden has had a lifelong passion for computer programming and electrical engineering, and recently has become interested in its relationship with biomolecular sciences. He has run a personal website since he was 15, which has changed names from HardenTechnologies.com, to KnightHacker.com, to ScottIsHot.com, to its current SWHarden.com. Scott has been in college for 10 years, with 3 more years to go. He has an AA in Biology (Valencia College), BS in Cell Biology (Union University), MS in Molecular Biology and Microbiology (University of Central Florida), and is currently in a combined DMD (doctor of dental medicine) / PhD (neuroscience) program through the collaboration of the College of Dentistry and College of Medicine (Interdisciplinary Program in Biomedical Science, IDP) at the University of Florida in Gainesville, Florida. In his spare time Scott builds small electrical devices (with an emphasis on radio frequency) and enjoys writing cross-platform open-source software.

Permanent link to this article: http://www.SWHarden.com/blog/2009-01-20-653-diy-ecg-detected-an-irregular-heartbeat/


  1. Kyle

    Hey here is an idea for you, get a control. Ask your wife if you can analyze her heart beat. This will give you a control of sorts. At least you will be able to determine if there is a inconsistency in the machine. Also remove distractions, a sudden movement or event could increase blood flow and the rate your heart is beating. Or if you want to be really cool hook up some rats and monitor their heart rate right before you remove them of their heads.

  2. Scott

    lol, good ideas. Rats and mice are hard because I’d have to make tiny electrodes, and I imagine that it would require much more signal amplification. I’ll definitely use my wife as a control though. I wonder if she’d be up for letting me tape some ewie gewie electrodes to her chest.

  3. Lucas Barbosa

    hy. Nice work uve done. About this irregular heartbeat, it looks like to me to be a supraventricular extrasistole. U can notice a wave similar to the “p wave” just before the irregular hearbeat. Also it seens to be a compensatory pause after this extrasistole. But i am not shure. Can u measure the interval between this abnormal heartbeat and the next heartbeat, and then compare it with the other RRIs? Also, it is very interesting to notice an increased potential inversion rigth before the QRS complex, and that the first of the two coupled waves, wich should be the normal wave, is actually much more abnormal then the extrasistole wave. Anyway, have u checeked for that with your phisiology professor? If so, post here what he told u about this wave.

  4. Michael Phillips

    You’ve probably had loads of input on this by now. The irregular beat you’ve recorded is, as you intitially described, noise. Also described as artifact, of which there are many causes depending on the appearence, this particular one is less electrically based and more a “knock” on the electrode. If it were to be considered an ectopic, because it is wider and of a different morphology to the sinus rhythm displayed, it would be a ventricular ectopic. A regular ventricular ectopic should have a compensatory pause after (although rarely an interpolated ventricular ectopic can be seen which does not have a pause), this cleary doesn’t and the following sinus beat lands in the refractory period of the “ectopic” which would not normally conduct and if it did could lead to a dangerous ventricular arrhhythmia. Very good project by the way!

Leave a Reply

Your email address will not be published.

You may use these HTML tags and attributes: <a href="" title=""> <abbr title=""> <acronym title=""> <b> <blockquote cite=""> <cite> <code> <del datetime=""> <em> <i> <q cite=""> <strike> <strong>