Torsades de pointes vs Ventricular fibrillation

[ShaneNg]

Hi guys, I have some doubts regarding the topic above, I've read a similar thread post last year but I have more questions to ask.

1) Differentiating 2 of them morphologically
I know sometimes it's quite obvious, but sometimes it's not. Some books say TdP has spindle shaped appearance and varying QRS height(higher in TdP) and morpholoy but this week we got an ECG strip during class which wasnt long enough to show the spindle shape. So, are there any cutlines between these 2?
2)The case was an MI, person was given some drugs and later went into cardiac arrest with the strip taken during showing polymorphic ventricular fibrillation(which I still cant really tell it's morphology apart from a TdP.
a-Anyway, say if it's a ventricular fibrillation
Does it count as a polymorphic Ventricular tachycardia? Because I read that polymorphic VT is more associated with Ischemia rather than infarct.
Or, it might be a re-entry loop established by the infarct border.
Or, it might be a VF which degenerated from TdP?
are these assumptions true?

b-Say, if I still think it's a TdP
Does a patient with TdP presents with the same status(cardiac arrest) as ventricular fibrillation? Or byitself it's not able to cause cardiac arrest and has to degenerate to VF to cause cardiac arrest?

Thanks

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[Dwindlin]

Hi guys, I have some doubts regarding the topic above, I've read a similar thread post last year but I have more questions to ask.

1) Differentiating 2 of them morphologically
I know sometimes it's quite obvious, but sometimes it's not. Some books say TdP has spindle shaped appearance and varying QRS height(higher in TdP) and morpholoy but this week we got an ECG strip during class which wasnt long enough to show the spindle shape. So, are there any cutlines between these 2?
2)The case was an MI, person was given some drugs and later went into cardiac arrest with the strip taken during showing polymorphic ventricular fibrillation(which I still cant really tell it's morphology apart from a TdP.
a-Anyway, say if it's a ventricular fibrillation
Does it count as a polymorphic Ventricular tachycardia? Because I read that polymorphic VT is more associated with Ischemia rather than infarct.
Or, it might be a re-entry loop established by the infarct border.
Or, it might be a VF which degenerated from TdP?
are these assumptions true?

b-Say, if I still think it's a TdP
Does a patient with TdP presents with the same status(cardiac arrest) as ventricular fibrillation? Or byitself it's not able to cause cardiac arrest and has to degenerate to VF to cause cardiac arrest?

Thanks

In regards to the bold, I have never heard v-fib referred to as polymorphic, its always just been v-fib. By definition its electrical chaos. TdP still should have a recognizable pattern to it.

a) No, v-fib does not equal polymorphic v-tach. But nearly any v-tach rhythm can degenerate to v-fib, though I don't think you would have any indication of that just from the ECG strip alone (assuming you are staring at v-fib).

b) TdP can present as cardiac arrest (just like regular old monomorphic v-tach), but can also present as a perfusing rhythm.

 

[kl323]

Vfib is chaotic.

TdP definitely has some sort of pattern. It's not easy to see it. But its definitely more organized thann a fibrillation.

 

[OveractiveBrain]

Studying cardiac arrythmias from the perspective of Cardiac Physio can frustrate things as nuances are brought to the surface. Once you hit ACLS, you will realize how differentiating the two really doesn't matter.

(1) Management drives understanding
Pulseless Vtach / Vfib / Torsades are treated exactly the same. Compressions, Ventilations, Shocks q 2 minutes, alternating between Amiodarone and Epinephrine (aka "Antiarrythmic and Vasopressor"). The unique caveat to Torsades, that, if diagnosed on EKG, you can give Magnesium to convert the rhythm. Electricity can convert Torsades. Amio can convert Torsades. Mag can convert torsades, but cannot convert Vtach/Vfib.

Vtach may have a pulse. Vfib never has a pulse. Torsades usually does not.

Terminology
What is usually referred to as "Vtach" is technically monomorphic ventricular tachycardia. Monomorphic (one shape) ventricular (Wide QRS without p waves) tachycardia (fast).

Polymorphic ventricular tachycardia refers to anything else polymorphic (more than one shape) ventricular (wide QRS without p waves) tachycardia (fast). Torsades is a polymorphinc ventricular tachycardia. Vfib is a polymorphic ventricular tachycardia. There are other things that can be polymoprhic ventricular tachycardia.

EKG Criteria for Torsades
Imagine what Torsades represents. This will be challenging in written text, and is very easy to comprehend if you can see my hands in three dimensions. Hold a football in your hand, pointed up in the air. Imagine that a single impulse to contract comes from the center of the ball, right in front of you. Each successive beat comes from a center in the same plane as that signal, but goes around the ball. The first beat starts in your face, then goes away, away, away, a final beat as far as possible from your face, then each beat begins to come towards you. Can you visualize how the points of impulse turn around the football?

Torsades de Point means twisting of the points.

Your face is the EKG lead, the camera watching these impulses occur. The one that is right in your face will have a very large amplitude. The one one on the opposite side of the ball will have a very low amplitude. The ones along the side going away from you will start large, and progressively get smaller. The ones along the side coming towards you will start small, and progressively get larger.

You must have a several seconds (10) of strip to see the QRS complexes start small, get larger, larger, larger, smaller, smaller, smaller on repeat to definitively diagnosis Torsades.

The most important thing is to be able to identify it by looking at it, you will have seconds to diagnose the rhythm in a code. If you arent sure, stick to the ACLS guidelines for VT/VF arrest = amio, epi, compressions, shocks

 

[da8s0859q]

Vfib is chaotic.

TdP definitely has some sort of pattern. It's not easy to see it. But its definitely more organized thann a fibrillation.

Agree. If looking at the tracing makes you think of the words "spindle," "twisting," or "ribbon," it's torsades.

 

[ShaneNg]

Hey guys, thanks for all the replies.

I'll try identifying it on a longer strip.

But Overactivebrian, I think you're right, as long as I skip MgSO4(I read that it may worsen VT, thought I'm not sure it's Poly or Mono it's referring to) and defibrillation should work for all.

Thanks