[HN Gopher] Engineers develop wearable heart attack detection te...
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Engineers develop wearable heart attack detection technology
Author : PaulHoule
Score : 65 points
Date : 2025-05-07 17:32 UTC (4 days ago)
(HTM) web link (medicalxpress.com)
(TXT) w3m dump (medicalxpress.com)
| krunck wrote:
| How do you get a decent ECG with a wearable that has a single
| point of contact with the skin. If you need to touch a contact on
| the device to get a two lead equivalent ECG then how can this be
| real time monitoring?
| ashwinsundar wrote:
| Real-time monitoring and continuous monitoring are different
| goals. The use case for something like this is probably a
| wearer who is experiencing heart palpitations, and has the time
| and clarity of thought to actually find the correct app on
| their device and start recording.
|
| Continuous monitoring is extremely challenging still because
| ECG data needs to be sampled at a relatively high frequency
| (~200 Hz) to accurately identify the QRS complex in the
| waveform. That uses a lot of power, and the batteries we have
| still aren't good enough to support those types of demands. 200
| * 60 * 60 = 720,000 samples per hour to collect and process.
|
| It's possible that algorithmic approaches may be able to reduce
| the sampling frequency required. Power-constraints were the
| main issue when I studied this topic 10 years ago during my
| master's degree. I had looked into non-frequency domain
| techniques (such as empirical mode analysis/Hilbert-Huang
| transform) as a possible way to reduce sampling frequency and
| thus power consumption.
|
| https://github.com/AshwinSundar/Empirical-Mode-Decomposition...
| sneak wrote:
| i would imagine you could take an ekg for 1-2 seconds every
| 30 seconds and run it through a much more simple model to
| determine if it should take a longer sample, no?
|
| rather than reducing the frequency of the sampling,
| dynamically adjust the duty cycle of when sampling is
| happening?
|
| this is probably a dumb suggestion, it seems pretty obvious.
| for example the apple watch doesn't do o2 monitoring
| continuously, just for some fraction of the time.
|
| do you need to sample every second to detect heart attacks?
| don't they continue to show up on an ekg for more than 30
| seconds?
| elric wrote:
| > apple watch doesn't do o2 monitoring continuously, just
| for some fraction of the time
|
| Making it effectively useless? Unless the fraction of the
| time is multiple times per minute? E.g. in sleep apnea it's
| not uncommon for some desaturation to occur, triggering an
| arousal and deeper breaths, restoring saturation, only for
| the cycle to repeat 2 minutes later.
|
| My Garmin has a similarly useless feature. I have no idea
| what the supposed benefit is. Maybe they hope that if they
| sample multiple nights they can detect some desaturation
| anyway and can get the user in for polysomnography? Might
| be worth it.
| jml78 wrote:
| I have mild sleep apnea and my Apple Watch is the reason
| I figured it out. If you wear it every night, you will
| catch it. I have on average 1-2 events an hour. Even with
| that few, the Apple Watch would catch the O2 drop enough
| times over a month that it worried me to see my O2 drop
| under 90%
| firesteelrain wrote:
| Fitbit supports detection of Afib and has FDA approval. It's
| not entirely out of the realm of possibility that one day it
| could also receive approval to detect heart attacks. It
| probably already has the data that might lead a savvy user to
| infer it just by looking at elevated resting heart rate, SpO2
| differences, and irregular heart rhythm alerts.
| lazyasciiart wrote:
| My Fitbit record showing heart rate spikes to 125 was one
| of the things that I noticed that suggested I was having a
| heart attack in 2020 (I was).
| stavros wrote:
| Hm, why is 125 a heart attack? Isn't that a fairly normal
| heart rate for exertion? Or were you just at rest?
| firesteelrain wrote:
| GP could have been having a non STEMI heart attack.
| lazyasciiart wrote:
| I was, actually, but I don't know how that's connected?
| This was something like a ten minute spike in the middle
| of the night, a couple of times.
| firesteelrain wrote:
| The sympathetic nervous system activates, increasing
| heart rate and the body is trying to compensate for the
| compromised heart muscle. Then, there is the possible
| adrenaline surge because you are actually in pain. If the
| NSTEMI causes left ventricular dysfunction, the heart
| compensates with a faster rate to maintain blood flow.
|
| I went through this with a relative just two weeks ago
| and learned this from the cardiologists
| lazyasciiart wrote:
| I was lying down at rest.
| vlovich123 wrote:
| There are audio recorders like TileRec by Attodigit that can
| record for 30 hours on a single charge and voice is recorded
| at 16khz and compressed live to mp3 and is super tiny at
| 0.5z. I'm thoroughly unconvinced that power or complexity of
| handling a 200hz signal is the bottleneck. 200hz is nothing
| probably even to a low end microcontroller these days.
| hwillis wrote:
| This is out of my specific expertise, but the AFE1291 does 8k
| 24 bit samples per second and uses 495 mW when sampling.
| That's enough to run full rate for 10 straight days on an
| apple watch battery (1.189 Wh was the first google result).
|
| Integrated frontends have had big impacts on efficiency and
| improving batteries have had basically the same increase in
| specific energy. I would be shocked if power was a limiting
| factor.
|
| https://www.ti.com/lit/ds/symlink/ads1291.pdf?ts=17469713549.
| ..
| avs733 wrote:
| There's a strong history of useful signals from single lead
| ecgs.
|
| Detection of ecg anomalies(especially episodic ones with
| intermittent recording) was the subject of the physionet
| cardiac computing challenge almost 10years ago[0].
|
| It's amazing how far machine learning has come. I know teach a
| version of this challenge as a one day in class activity in my
| department's physiology class. They actually get to train
| multiple models on a gpu cluster (and compare that to trying to
| train models on their laptops).
|
| One thing we reinforce in the lesson is human vs. computer
| "interpretation". They/clinicians can look at ecgs and make
| some sense of them. An LTSM is worse than random chance/a
| medical student. However moving to the frequency domain makes
| the LTSM more accurate than cardiologists, but neither they nor
| clinicians can "see" afib ina spectrograph. It's a great way to
| talk about algorithmic versus human reasoning and illustrate
| that to students.
|
| That then gets reinforced with other case studies of the ying
| and yang of human and machine decision making throughout our
| curriculum- like alpha fold working great until you ask it
| about a structure in the absence of oxygen, because that's not
| in its training data.
|
| [0] https://physionet.org/content/challenge-2017/1.0.0/
| closewith wrote:
| > There's a strong history of useful signals from single lead
| ecgs.
|
| But to be clear, a single lead ECG requires two electrodes at
| a minimum and commonly a third as ground. So a single lead
| ECG will have minimum two cables attached to electrodes on
| the patient. The placement depends on which lead (eg lead I,
| lead II, etc) but there's always two minimum.
| elric wrote:
| Article seems very light on details. Is this trying to detect ECG
| markers of heart attacks (like ST segment issues)? Is it somehow
| detecting troponin in the blood stream? How? And how are they
| going to prevent false positives if this is indeed a wrist-based
| device as I imagine it will be?
| user_7832 wrote:
| It seems to be using ECG, the (correct) springer link is
| https://link.springer.com/chapter/10.1007/978-3-031-82377-0_...
| elric wrote:
| Can't read the full article. Abstract mentions 92% accuracy.
| That could be abysmal depending on how it's calculated?
| Correctly identifying 92% of heart attacks and missing 8%
| might be pretty good. But reporting false positives 8% of the
| time would be awful.
| bobmcnamara wrote:
| Even 'return false' would best 92% accuracy.
| closewith wrote:
| Yes, global afib prevalence is about 1-2%, so return
| false would be 98-99% accurate, which is why accuracy is
| not a metric used to assess medical diagnostics.
|
| However, the sensitivity of return false is 0%, which
| renders it useless (and why sensitivity and specificity
| are used in this context).
| absolutelastone wrote:
| I suspect it's probably worse than that in reality. From a
| quick search on state of the art ECG results (the full
| system of leads attached all over your torso) it looks like
| around 90 percent specificity (True negative rate) and
| under 50 percent sensitivity (true positive rate). So it's
| only pretty good at ruling out heart attacks, but still
| misses them sometimes. But is pretty bad when it comes to
| false alarms. I think they use it along with multiple other
| tests and consideration of symptoms in triage at the
| hospital.
| ETH_start wrote:
| This kind of technology has been technologically viable for
| decades. The fact that we're only now seeing prototypes, not mass
| adoption, is an indictment of the legal framework around medical
| devices.
|
| The FDA classifies these devices as high-risk because they might
| give a false result but completely ignores the guaranteed harm of
| not having them at all. It's a system that punishes action and
| rewards delay.
| dennis_jeeves2 wrote:
| >is an indictment of the legal framework around medical
| devices.
|
| Well medical devices aside, the legal framework around
| anything, including business, manufacture etc. is more impeding
| while failing to address things like environmental
| destruction/pollution which causes real harm. ( notice, that I
| did not say climate change, a separate subject).
|
| It all makes sense when one sees it either though the lens of
| either corruption of more likely human stupidity - where a
| bunch of rules give people the comfort of being protected.
| avalys wrote:
| There's no "might" here, in a device advertised as "92%
| accuracy". This device _will_ give false results, almost
| certainly an overwhelmingly number of false results relative to
| the actual heart attacks it detects. And those false results
| have real, guaranteed harm and cost as well.
|
| Both false positives and false negatives are harmful. False
| positives will send people to the hospital for no reason and
| divert resources from people with real emergencies - not to
| mention leaving them with a large ER bill to pay. False
| negatives will result in people with actual heart attacks
| dismissing their symptoms and dying.
| vlovich123 wrote:
| The counter is that people can build their own informed
| intuition about whether these things are helpful,
| particularly in coordination with their doctor and experience
| of using it. And a product is easier to improve and will
| improve more quickly if the company can easily bring updates
| and find investment that improve quality to product they have
| revenue for.
|
| I think the FDA safety margin for things like this should be
| more "this has no actual obvious harm to use, it has a
| plausible mechanism of action to help + isn't fraudulently
| measuring what it claims to measure and its science backed.
|
| Something like this hits all the targets already.
| absolutelastone wrote:
| I agree the legal restrictions (and liability) should be
| looser. But other countries are pretty bad about this too in my
| experience. It's more of a medical establishment monopoly thing
| it seems.
|
| Also you can already buy home ECG devices for a couple hundred
| bucks. Not sure if there is some history of being banned in the
| past or whatever, but otherwise I'd guess the main problem is
| just a lack of much interest in the market.
| hwillis wrote:
| What is burdensome about the regulations? They are here:
| https://www.fda.gov/medical-devices/guidance-documents-medic...
|
| They allow a summary report. They don't require a clinical
| human trial. They barely care if you follow the FCC and safety
| requirements for electronics in general. This does not look
| burdensome.
| neiesc wrote:
| Awesome
| croes wrote:
| Is the ECG for a heart attack the same for women and men?
|
| The symptoms aren't.
| hwillis wrote:
| The most common heart attack symptoms are the same for men and
| women. The less common, less diagnostic symptoms are more
| common in women. Over time the medical opinion has swung back
| and forth (eg thinking women had less pain, until it was
| recognized that many men have heart attacks without pain) but
| the current consensus is that the important symptoms are pretty
| much the same between men and women. Women may be more likely
| to experience nausea during a heart attack, but you can't use
| nausea to diagnose a heart attack and men get nauseated a
| similar amount. These symptoms also don't take into account
| body types, which have a big impact on the type of attack and
| symptoms.
|
| Men and women have slightly different ECGs and a doctor can
| usually tell your gender from an ECG. The appearance of a heart
| attack will be more similar than a normal heartbeat. Gender
| differences have a much smaller impact on an ECG than things
| like body mass and blood pressure. Overworked hearts will look
| more like overworked hearts.
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