ECG Application for Diagnosis - Page 1
Forum section: electronics / projects

author: seekingforprogress
author_rank: Newbie
timestamp: December 19, 2016, 08:58:46 am
content: Can I built a quality ecg circuit to diagnose some heart disease using ad8232. Also,it must be suitable for wearable projects

author: Buriedcode
author_rank: Super Contributor
timestamp: December 19, 2016, 05:08:33 pm
content: Have you googled?I don't think I would trust any DIY effort to 'diagnose heart disease' - thats why medical equipment is so expensive, it has to under go rigorous testing to ensure it is accurate to a degree, and reliable enough to make life/death decisions. Also, medical equipment doesn't *diagnose* disease trained medical staff do, and often from the results of several tests rather than just one.But just for interest there is these:http://www.gammacardiosoft.it/openecg/getting_started.htm#build_yourselfhttps://hackaday.io/project/10565-openecghttp://www.swharden.com/wp/2016-08-08-diy-ecg-with-1-op-amp/As with all things 'medical', the electronics is the easy (and often cheap) part. Its the things like reliable electrodes and the hassle of hooking yourself up for measurements thats the annoying part.

author: filssavi
author_rank: Frequent Contributor
timestamp: December 19, 2016, 06:24:36 pm
content: Quote from: Buriedcode on December 19, 2016, 05:08:33 pmThe electrodes aren't the problem either, you can get the semi-decent stuff so, I highly dout you'll find some non-fake branded ones, but you should be able to find the no name ones for pretty cheap on ebayAs the Buriedcode said the real problem is the Degree in medicine and the sepecializzation in cardiology thay you must have to be able to reliably interpret the waveforms you get, even to get close you'll have to have education in the medical field (chose between medicine, nurse or paramedic if available in your country).shure you might pick up the easy stuff like VF but I'd like to point out that it's also quite easy to spot that condition by what is colloquialy called "the patient is litteraly dying before you and he should be defibrillated ASAP or he probably won't make it"And beside that even if you could spot some kind of heart malfunction with your unsafe DIY ECG what are you going to do about that DIY prescribe yourself (or anyone else you want to diagnose) potentialy deadly medicines? of course not (or at least I hope so), you'll have to go to a cardiologist after all and get a professional ECG done so why botherthat leaves me thinking that either:1) you want to build yourself an ECG machine to learn about electronics and try to read some ECG just for fun, if this is the case I would advise you to clarify your intentions2) you want to try and diagnose something on yourself, and if so go ahead and do so risking your life but I don't think you ll'find many peoples that want to help you with that3) (and I really, really hope it's not this one) you are some kind of DIY/wannabe doctor and you want to try and diagnose other peoples with your makeshift apparatus, if so you might want to contact a lawyer and talk to him about the legality of what you are trying to do

author: chris_leyson
author_rank: Super Contributor
timestamp: December 19, 2016, 08:38:15 pm
content: In principle I don't see why not. An AD8232 would give you a basic three electrode system with the third, leg eletrode, being driven by a voltage out of phase with the common mode voltage from the other two electrodes. Dealing with common mode interference, especially asymmetric common mode where the common mode voltages on the other two electrodes are not the same, is always going to be a problem and some systems add an extra leg electrode to overcome this.You also have to be aware of "patient" leakage currents, so for ECG you would have to meet or exceed the requirements of IEC 60601-1 for BF applied parts. Also, as you said it must be suitable for wearable projects then it should not be too difficult to meet the leakage current requirements.

author: seekingforprogress
author_rank: Newbie
timestamp: December 23, 2016, 10:29:49 am
content: that leaves me thinking that either:1) you want to build yourself an ECG machine to learn about electronics and try to read some ECG just for fun, if this is the case I would advise you to clarify your intentions2) you want to try and diagnose something on yourself, and if so go ahead and do so risking your life but I don't think you ll'find many peoples that want to help you with that3) (and I really, really hope it's not this one) you are some kind of DIY/wannabe doctor and you want to try and diagnose other peoples with your makeshift apparatus, if so you might want to contact a lawyer and talk to him about the legality of what you are trying to doI am just a student

author: seekingforprogress
author_rank: Newbie
timestamp: December 23, 2016, 10:32:50 am
content: I think i couldn't use ad8232, because I need to design instrumentation amplifier and the other by myself

author: VK5RC
author_rank: Unknown
timestamp: December 23, 2016, 11:05:59 am
content: There are some purpose built ECG (EKG in USA) amps with great CMMR and 50-60Hz filtering. For ECG interpretation you need 9 channels (3 limb leads, one limb "earth" and the 6 across the chest leads). Learning just how to interpret ECGs properly is probably a one month full-time exercise, but you need to have quite a background in cardiac electrophysiology and pathology for it to really gel.The book "The ECG made Easy" has been a classic for 3 decades or so but it is only the start.

author: chris_leyson
author_rank: Super Contributor
timestamp: December 23, 2016, 11:08:48 am
content: Hi, I think the AD8232 has the instrumentation amplifier built in, Sparkfun sell an AD8232 evaluaion boardhttps://www.sparkfun.com/products/12650and there is good guidehttps://learn.sparkfun.com/tutorials/ad8232-heart-rate-monitor-hookup-guide. A simple three electrode ECG will get you started and then you could look at adding more electrodes. As VK5RC noted some systems have up to 9 channels.

author: seekingforprogress
author_rank: Newbie
timestamp: December 23, 2016, 11:37:15 am
content: I think, I am going to use this electrode placement and start to design with INA826 for instrumentation amp after that opa333 for re amplification

author: VK5RC
author_rank: Unknown
timestamp: December 24, 2016, 06:38:16 am
content: That intro on Sparkfun is quite nice, esp the dynamic heart picture and ECG trace. Values of time and voltage are reasonably critical - most ECGs are 'printed out' to a common scale both in time (X axis) and voltage (Y axis) - see picture below

author: Karel
author_rank: Super Contributor
timestamp: December 24, 2016, 07:36:24 am
content: Quote from: chris_leyson on December 19, 2016, 08:38:15 pmThat was in the past, now a professional medical ECG device must comply with the additional norm 60601-2-25 which says that itmust comply with CF applied parts (cardiac floating) which has even lower patient leakage current(less than 10uA @ normal condition and less than 50uA @ single fault condition).But for battery operated portable devices without any connectors (apart from the ECG leads) that shouldn't be a problem.

author: Karel
author_rank: Super Contributor
timestamp: December 24, 2016, 07:39:18 am
content: The simplest way to build an ECG device is to use this guy:http://www.ti.com/product/ADS1298

author: m98
author_rank: Frequent Contributor
timestamp: December 24, 2016, 03:38:41 pm
content: Quote from: Karel on December 24, 2016, 07:36:24 amEven with a mains power plug/USB-connector for charging and data exchange, you just have to use a decent digital isolator and an EN60601 certified DC/DC converter and adequate creepage distance and maybe even isolation slots to the floating patient front-end circuit.Someone wrote that getting the right electrodes is an issue, it isn't. Wonder where your doctor gets them from?For example:https://www.amazon.com/Red-Dot-Multi-Purpose-Monitoring-Electrode/dp/B002C2M90I/ref=sr_1_1?ie=UTF8&qid=1482593056&sr=8-1&keywords=ecg+electrodes

author: chris_leyson
author_rank: Super Contributor
timestamp: December 24, 2016, 04:39:25 pm
content: QuoteThanks, hadn't realised it had changed.