A similarity between the CAP theorem and our heart

[lgeorget]

The funny thing about all that "decentralization" and the fact that the heart doesn't need the central nervous system to work is that the pulmonary system does need it. So on the one hand, it's great, your heart can function on its own, on the other hand, you cannot breathe without a working brain.

Time to finish that refactoring, evolution! One component is over-engineered with respect to the rest of the system.

[bheadmaster]

Evolution: Well, our milleniums-long testing indicates that adding decentralization to pulmonary system is not the highest prority right now, as the blood already provides an oxygen cache - in case of pulmonary failure, we have a couple-minutes window to restart it before any permanent damage occurs. You can add it to the backlog, and we'll get to it when we have time.

[DVassallo]

Indeed, although I believe the main value of the automaticity of the heart isn't about being able to survive brain failure, but about being a real-time system with no dependencies. Unavailability of just ~3 seconds can lead to loss of consciousness. We can afford to stop breathing for a bit if the nervous system is overwhelmed, but the heart can't afford that.

[fxj]

It is interesting that we always think about things that would be favorable for humans, but there are plenty of mammals out there which can hold their breath for minutes, almost hours. Think about whales or dolphins. It would not make much sense for them when the lungs start breathing by themselves. On the other hand, the heartbeat of some mammals slows down when they are under water to spare oxygen.

[irdc]

Since the breathing regulation centre is located in the medulla oblongata region of the brain stem, one can miss a surprisingly large amount of brain before one’s breathing stops.

Of course, if the event that causes one to miss part of one’s brain also induces swelling of the remainder all bets are off.

[rolisz]

Would that mean that if we had decentralized pulmonary control, we wouldn't be able to hold our breath?

[hoseja]

Bah, that's what you landlubbers get for trying to use gaseous oxygen.

[IIAOPSW]

yeah, but then you'll want the central nervous system to be able to fiddle with the state anyway in order to do things like holding your breath while swimming, at which point the autonomous system is redundant and you may as well just have the brain manage the breathing state directly.

[throwaway_15axd]

I'm not a cardiologist (so take my comment with a pinch of salt). But I was an avid runner (running average 10km a week for 2 years) but a few years later, I developed a form of Ventricular Tachycardia called RVOT.

I went for a battery of tests similar to the OP. The results shows my heart is structurally OK. The doctor diagnosed that I had RVOT and recommended I do ablation. He says that this is a very very common procedure.

I did the procedure. However, the symptoms started coming back again.

After reading this article, I wonder if I should have just left my heart as is.

[low_tech_punk]

Glad you mentioned this. I'm a avid biker and endurance runner. I'm diagnosed with PVC a few years ago. I went through two rounds of ablation, both failed. Now I take Flecanaide to keep the rhythm but I want seek second opinion now, thanks to this tweet.

[appplication]

My next door neighbor was a moderately healthy dude in his 60s. Went in for an ablation, had complications, died two weeks later. All cardiac procedures are risky.

[dfc]

10k a week is avid running?

[SirSegWit]

Came for the CAP theorem, stayed for the cardiology 101 course, lol. His approach to diagnosing himself is really admirable. Working with doctors but never fully trusting them w.r.t. completeness is unfortunately the way to go in these busy times, where doctors just assume the most likely diagnosis and move on. Luckily, we have almost the same information available as the doctors with studies and such that we can dig deeper ourselves.

[aneutron]

I can't really blame them. The essence of it is "if you see hooves think horses not zebras".

The human body is usualy one resilient bastard, so the ol' "tylenol and come back if it gets worse" is a good tactic for 95% of the cases.

But detecting those 5% cases probably takes A LOT of dedicated bandwidth from the whole medical process, so unless there is some clear manifestation that it's not horses but something else, I think it is reasonable that some will not investigate further.

[samspenc]

Science / health aside, I think this is the longest Twitter post I've read posted as a single tweet (instead of a thread). I knew that Twitter had relaxed some length limits but I didn't realize it was possible to post a (checks in text editor) 10,000 character or 1,800 word article in a single tweet these days.

[paws]

I believe this is only available to paying members with a blue check.

EDIT: "this" meaning posting

[workfromspace]

https://nitter.net/dvassallo/status/1716585205400756514 (original twitter URL requires JS to be enabled, nitter doesnt)

[bluepizza]

If you have PVCs and find yourself worried, remember that the author is an endurance runner.

Coffee and anxiety also cause PVCs, which are really harmless.

[mo_42]

I showed this text to a friend who works in internal medicine (so not a cardiologist but probably much closer than most commenters).

Basic comment was that the person confuses and misunderstands many things. According to my friend, the range marked as "missed beat" contains a premature heart beat [1].

Some more comments:

- Premature hear beats happen in us quite frequently

- CT scans are a rather invasive diagnostic method and such be avoided

So unless some more competent doctor comments otherwise, I take this as a nice story that resonates well in our layperson's minds. Not more.

[1] https://en.wikipedia.org/wiki/Premature_heart_beat

[DrDroop]

CAP shows up in lots of places, my favourite is arrow's impossibility theorem.

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[poszlem]

PVCs are curious because many people have them and don't even realise.

But for those who do notice, they sometimes become super aware of every beat.

Feeling a PVC can make some people anxious, which boosts adrenaline, potentially leading to more PVCs.

It's like a feedback loop where a "missed beat" gets linked with that adrenaline jolt.

Most of the time, PVCs are no big deal. So, the best "fix" might just be learning to shrug them off, which often makes them happen less or go away (obviously after getting a green light from a cardiologist).

[latchkey]

This is an absolutely fascinating read.

[polishdude20]

I'm surprised an extra 30 mins per day of running for 6 weeks had enough of an impact to change the structure of the heart noticeably.

[DVassallo]

Author here. I've been taking running seriously for 22 months, so maybe the past 6 weeks were just the last straw to trigger this arrhythmia. I also had covid at the end of July (very mild symptoms), which made me think there could be a link, but the tests seem to exclude any lingering inflammation or infection.

[rojeee]

To provide some anecdata. I started running again a few years ago (I'm late 30s now but used to run competitively when I was younger). Before I started, my Oura ring tracked resting heart rate while sleeping at an average of 55 bpm. After 2 years of doing an average of 60km a week (mostly aerobic work), my resting heart rate averages at 39 bpm. I guess the difference is because the heart chambers are now larger - the structure of the heart has significantly changed.

Only after a couple of weeks of running about 20km, did I start seeing my resting heart rate drop to the high 40s. After that, it gradually lowered over the next 18 months or so.

Furthermore, an article about a study back in 2008 [1]:

> At the end of the 90-day study period, both groups had significant overall increases in the size of their hearts. For endurance athletes, the left and right ventricles — the chambers that send blood into the aorta and to the lungs, respectively — expanded. In contrast, the heart muscle of the strength athletes tended to thicken, a phenomenon that appeared to be confined to the left ventricle. The most significant functional differences related to the relaxation of the heart muscle between beats — which increased in the endurance athletes but decreased in strength athletes, while still remaining within normal ranges.

> “We were quite surprised by both the magnitude of changes over a relatively short period and by how great the differences were between the two groups of athletes,” Baggish says. “The functional differences raise questions about the potential impact of long-term training, which should be followed up in future studies.”

[1] https://news.harvard.edu/gazette/story/2008/04/exercise-chan...

[tw1984]

amazing article! best read in 2023.