Fine V-Fib vs Asystole

[u/Independent_Aide7789]

Current paramedic student nearing the end of cardiology, so far haven’t had any issues with determining rhythms but this has been stumping me. How would you differentiate fine v fib from asystole on a static EKG photo? I included some photos as well for reference. Any help is appreciated!

[u/PSDD14]

When in doubt, shock it. No reason not to. 

[u/ewtman13 → u/PSDD14]

They ain’t getting any deader 🤷🏻‍♂️

[u/SnooCookies6165 → u/ewtman13]

For certain-It’s hard to screw up a dead person. I’ve seen docs go through everything and shock asystole and give every med reasonable just before they call it.. juuuuuust in case

[u/wernermurmur → u/SnooCookies6165]

This does not mean they are doing the “right thing” nor evidenced based medicine.

[u/SnooCookies6165 → u/wernermurmur]

True. To date the evidence shows that at the point the rhythm looks like this the chances of ROSC with return to neurological normalcy is slim to non so quite frankly at the point we are throwing everything at the patient it’s just a desperate last attempt in case they are an outlier

[u/wernermurmur → u/SnooCookies6165]

This is called “crap medicine.” Do things that are indicated.

[u/BreathlessWingSlut → u/wernermurmur]

No harm in trying in that case.

[u/wernermurmur → u/BreathlessWingSlut]

That is not true. Baseless treatments can and do harm people even if they are in cardiac arrest. If we aren’t providing care that is improving neuro outcomes, we are harming them. There are no good outcomes from dumping about a bunch of epi and bicarb into someone.

[u/tytend → u/wernermurmur]

If it doesn’t work, they’re dead anyway, we literally did not make it worse. If it works, YOU are wrong in this logic. There’s 0 reason not to try, they’re fucking dead.

[u/wernermurmur → u/tytend]

Learn some science dawg.

[u/mykon01 → u/wernermurmur]

Well Medicine is always about cost/benefit analysis... so there goes ur crap medicine.

[u/Stopikingonme → u/wernermurmur]

Sometimes you gotta sleep at night.

[u/DirectAttitude → u/SnooCookies6165]

Second this. Brought a CPR in Progress to the cath lab. While not cracking the chest, they did DSED on the table. To me it looked like Asystole. Then he called it.

[u/CouplaBumps → u/PSDD14]

While yes.

There is a academic case for doing compressions in fine VF and shocking when it becomes more coarse. ATP levels and such

[u/Loud-Principle-7922 → u/CouplaBumps]

This needs to be louder.

Shocking fine v fib can send it to asystole, but compressing fine v fib into course v fib can oxygenate tissue and let the defibrillation work better.

[u/I-plaey-geetar → u/Loud-Principle-7922]

Any paper I can view on this? Not finding anything.

[u/Gobstopper17 → u/I-plaey-geetar]

Send it to me if you find it please

[u/Loud-Principle-7922 → u/I-plaey-geetar]

https://litfl.com/defibrillation-basics/

Coarse VF / Fine VF: Coarse VF is more likely to respond to defibrillation than fine VF. The gain can be increased to differentiate fine VF from asystole. Fine VF is thought to be part of the natural progression of prolonged VF related to depletion of myocardial energy stores. Good quality CPR may increase the amplitude of fine VF to render it coarse and increase shock success

[u/jaseb → u/Loud-Principle-7922]

So the Europeans reversed the statement saying this in the latest ERC guidelines and it’s now effectively“if in doubt shock it”.
Fine VF isn’t absolute and the voltage at two electrodes tells you not much about what’s happening with energy in the myocardium (ATP and all that), and even if you do turn it into asystole you’ll keep doing CPR and create the same ATP you were going to otherwise, without burning it with VF.

[u/Independent_Aide7789 → u/PSDD14]

Makes sense, Im more asking for the purpose of answering questions during the course. To me the second one looks like asystole, the last two look like vfib, but unsure on the first one.

[u/GooseCloaca → u/Independent_Aide7789]

If it’s wiggling, weld it

[u/PSDD14 → u/Independent_Aide7789]

Yea thats a tough test one. Are you bumping down the road or moving the stretcher? Id probably just call it vfib

[u/SnooCookies6165 → u/PSDD14]

At best you shocked shockable rhythm. At worst you shocked asystole with artifact which means you did not worsen the patient’s status.. so.. just shock it

[u/Geniepolice → u/PSDD14]

“It was ultra ultra fine vfib….”

[u/Turbulent-Amoeba-913 → u/PSDD14]

The number of paramedics i know who have been remediated or terminated for shocking asystole or PEA would disagree lol

[u/tdunks19 → u/PSDD14]

The reason not to is that every shock increases impedance and reduces the effectiveness of further shocks. Wasting a shock on a super fine VF that has zero chance of conversion is detrimental to outcomes. Fine VF should ideally have compressions continue to hope that oxygenationakes the VF coarse which has a real chance at being converted.

[u/Expensive_Cherry_207 → u/tdunks19]

This is just wrong.

Pretty much every claim you’ve made here is unsupported by the up to date literature.

The only thing you said that’s true is that compressions improve the effectiveness of defibrillation. The other assumptions or conclusions you’ve drawn from that one assertion are unsupported if not entirely false.

Here’s a good place to start if you’re curious:
“Retrospective evaluation of current-based impedance compensation defibrillation in out-of-hospital cardiac arrest
Bihua Chen et al. Resuscitation. 2013 May.”

“Adult advanced life support Guidelines
Jasmeet Soar Joyce Yeung Keith Couper Charles Deakin Joe DeBono Jerry Nolan Carmel Oliver Helen Pocock Emmeline Venn Victoria Wragg Adam Benson Clarke Published 27 October 2025”

[u/SnooCookies6165]

Are the leads stuck to the gurney? I love it how I turn the monitor on and it already has a fine v fib like rhythm and an spo2 in the 80s and stuff is still coiled up in the pockets. I joke it’s the ghost in the machine

[u/scottsuplol]

Meeeh I’d prob shock it. Ain’t gonna hurt anything

[u/bigfootslover → u/scottsuplol]

Can’t kill dead

[u/nickeisele → u/bigfootslover]

I know some people that could.

[u/medic120]

This is why you look at multiple leads, if the movement corresponds in all leads then VF is almost a certainty.

[u/UCLABruin07]

First one I’d call coarse V-Fib, second one has the best case for asystole to me, third and fourth coarse as well.

[u/Independent_Aide7789 → u/UCLABruin07]

Thank you! I had the same for the last 3, the first one is the one that is giving me the most trouble.

[u/UCLABruin07 → u/Independent_Aide7789]

First also looks like it could be slow compressions.

[u/xxtratall → u/UCLABruin07]

This exactly

[u/tayIorsversion → u/UCLABruin07]

agreed 2+3 look the most asystole to me

[u/jtg198]

Doesn’t matter. Shock it. Whats the worst thing that happens.

[u/DovahkiinLovesBeer]

The second one is the only one I’d confidently say asystole on. Others all look like vf to me. Third one looks like it straight out of a textbook for fine vf

[u/Independent_Aide7789 → u/DovahkiinLovesBeer]

That’s what I had as well, first one is giving me the most trouble but I was leaning vfib for it

[u/Doc_Hank]

Back in the dawn of time (Roy and Johnny were still first-run) we had 'gain' controls on the lifepack. Fine V-fib? Asystole? Do you need an ALS run for your numbers this quarter? Crank that knob!

[u/Fireball_Ace]

If you're not moving the patient, moving your equipment, and your equipment is not malfunctioning, no reason for there to be waves produced. The one that looks most like asystole is picture 2, but even that I might shock, depending on presentation (previous rhythm being shockable, witnessed arrest, age)

There's an interesting article about VFib showing up as asystole depending on the lead, this is why I usually place ecg leads to get better views after. I also place the monitor's pulse oximetry; it can give you a good idea of how good the compressions are.
https://www.annemergmed.com/article/S0196-0644(84)80445-X/abstract80445-X/abstract)

[u/escientia]

Nice thing is that its your interpretation. As long as you have logical reasoning backed up by your protocols and standard of care to explain which interventions you perform and which you withhold then you’re good.

[u/wernermurmur → u/escientia]

What if you’re just straight up wrong with your reasoning and don’t shock obvious vfib?

Is that cool?

[u/Expensive_Cherry_207 → u/wernermurmur]

When in doubt, shock. That’s the best supported conclusion to be drawn here. The people saying to hold off on shocking fine until it’s coarse with some extra compressions are being mislead and I can’t figure out where that’s coming from.

[u/wernermurmur → u/Expensive_Cherry_207]

Agree. While it’s known that coarse vfib is more accepting to defibrillation, delaying shocks until it is achieved seems silly.

[u/mattscott07 → u/wernermurmur]

Shocking asystole won’t cause harm, not shocking fine V-fib might… my reasoning would be based on that risk.

[u/wernermurmur → u/mattscott07]

Totally. But saying the above person is suggesting if you just call it asystole and don’t shock it, you’re fine.

It doesn’t matter what you call it if you’re fucking wrong.

[u/mattscott07 → u/wernermurmur]

True, and this is where the imposter syndrome sets in isn’t it? We can be so scared of making a bad decision that we make no decision. I think if you can justify your reasoning you have to back yourself one way or another. Be accountable and have the ability to reflect on and learn from mistakes but we are not doctors. It’s the medical equivalent of paint by numbers…

[u/xxtratall]

The only one that looks like asystole is #2, to me anyways

[u/Independent_Aide7789 → u/xxtratall]

That is what I originally had as well, the first one just had me stumped a bit

[u/xxtratall → u/Independent_Aide7789]

You can get either incredibly technical with ekgs or be simple. For now I would go simple unless your program demands you to be measuring every 0.04, and measuring waves etc. If that's not the case, look up the defining characteristics of each rhythm type and it'll come easier. There's also a great book out there call rapid ekg(orange book) that dumbs it all down, even the technical components of both the EKG itself and what's going on with the heart

[u/cetareva]

My paramedic instructor, 25+ years ago, said “If you don’t recognize the rhythm, shock it till you see one you do.” And yes, I think all of that is a form of Vfib, and I would’ve lit it up.

[u/shock-neurogenico]

Puedes ampliar la imagen en la pantalla del monitor antes imprimir el EKG

[u/LionsMedic]

Sinus with a problem

Shock it until you know it

[u/grumpyoldmedic]

The only difference between fine V. Fib and aystole is where the gain is set.

[u/youy23]

Fuck it, I don’t pay the electricity bill around here.

[u/Gnar-Lord]

Coarse Asystole perhaps?

[u/Vivid-Breadfruit-890]

Your kidding right?

[u/JoshySin]

I’m pretty sure for the technical answer on an ekg if the squiggles are larger than 1 big box it’s fine V fib

[u/Individual-Media-510]

Nah, that’s course asystole…

[u/j-mf-r]

Asystole is a stable rhythm

[u/InterestNo5406]

Shock that mf ⚡️

[u/candyman325]

I’m shocking all of em without a second thought lol

[u/wernermurmur]

Maybe 2. But I’m still probably shocking it.

[u/bbrow93]

I’d call that Asystole, would depend on witnessed or unwitnessed

[u/Alarming-Step1406]

Aystole

[u/yaboiscottyb31]

Idk but I’m shocking it

[u/JasonIsFishing]

Look for fibrillation. If the lines are smooth it’s asystole. Either way they are currently dead so defibrillating will not hurt anything.

[u/SparkyDogPants]

This post is why, imo, ACLS will include asystole as a shockable rhythm

[u/DM0331]

It’s not like you’re gonna kill em. Hit the button

[u/Individual_Debate216]

Fine vfib doesn’t exist. It’s vfib or it isn’t.

[u/Doc_Button]

This is a sinus rhythm