Let's talk electricity

[adamjh3]

I have a question that I haven't been able to find an answer to.

Why is pulseless VT not synchronize cardioverted at a high energy setting and rather just defibrilated?

To me it would make more sense to synchronize your shock with any VT so that the electricity is delivered at a point where it will potentiate the natural depolarization of the heart.

 

[truetiger]

By synchronizing, you're going to deliver the shock at the optimal point. An unsynchronized shock poses greater a risk of converting your patient with pulses to v fib.

 

[adamjh3]

Right, but my question is in regards to pulseless V-Tach. Why is this rhythm defibrillated rather than sync-cardioverted?

 

[NYMedic828]

By synchronizing, you're going to deliver the shock at the optimal point. An unsynchronized shock poses greater a risk of converting your patient with pulses to v fib.

I believe that's what he is asking.

Seems he is saying why do we defib a pulseless VT since it could cause vflb versus just syncing to be safe.

I would like to know the reason why as well. Maybe at that point it is just optimal to attempt a full reset of the heart instead of trying to break a piece of the chain.

 

[Aidey]

In monomorphic VT you can synchronize cardiovert. I was always told that in polymorphic VT it is harder to synch properly so they recommend unsynchronized cardioversion.

 

[adamjh3]

I would like to know the reason why. Maybe at that point it is just optimal to attempt a full reset of the heart instead of trying to break a piece of the chain.

Cardioversion is also a mass depolarization of the heart, just at the same time that the heart is naturally depolarizing. I guess that's where I'm getting hung up.

The answer must lie in a difference in pathophysiology between VT and VT with pulses.

 

[truetiger]

They throw pulseless v tach in with v fib to reduce any delays in delivering the shock. As Aidey said you can synchronize if its a nice monomorphic v tach. Polymorphic v tach can be difficult for the computer to synch.

 

[FLdoc2011]

They throw pulseless v tach in with v fib to reduce any delays in delivering the shock. As Aidey said you can synchronize if its a nice monomorphic v tach. Polymorphic v tach can be difficult for the computer to synch.

I would tend to agree with this... Since now you're going down ACLS so they could keep it simple and avoid delays in shocks.

Interesting question though an honestly I don't recall hearing specifics of why they're treated differently. Will have to do some reading.

 

[truetiger]

By synchronizing you're going to hit the heart on the R wave, and not on the relative refractory period. If you hit the heart during that, there's a decent chance of putting the patient into v fib. So you synchronize you're patient's with pulse because its more effective and less likely to induce fib.

 

[adamjh3]

By synchronizing you're going to hit the heart on the R wave, and not on the relative refractory period. If you hit the heart during that, there's a decent chance of putting the patient into v fib. So you synchronize you're patient's with pulse because its more effective and less likely to induce fib.

And that's exactly what I was thinking. ACLS teaches pulseless VT gets defibbed, but that didn't quite make sense to me.

 

[Brandon O]

Pulseless VT is treated exactly like pulseless VF because it's an emergency of (essentially) the same degree. They don't want you flipping through your flowchart or trying and failing to synchronize; they just want you electrocuting the dead guy before he gets any more dead.

One of those "break out of the loop" things. Do not pass go, do not consider risk vs. benefit. The odds of "worsening" an already pulseless rhythm are pretty dismal in my opinion, and you could always shock again, but you can't buy back lost time. That's my understanding anyway.

 

[Melclin]

I was taught at uni to sync the shock for pulseless VT.

Didn't know enough at the time to question the difference between that teaching and the recommendations of various peak bodies.

I'd be interested to know if it would be better to sync during VT. It makes sense to do it.

 

[ZootownMedic]

I'd have to agree with Brandon. Time= Muscle. If they are pulseless than delaying treatment is the worst you can do for your patient. CPR, Weld em, and reassess makes sense.