Heart rate: 310

[JPINFV]

We were replying to someone else who confused a Valsalva maneuver [blowing up a glove or blowing through a straw] with rebreathing to increase PaCO2.

[Scaramedic]

First of all, when you have someone who has a HR above 180, acording to every class I have ever been to says, while you are getting the IV prepared have the patient do "Vagal maneuvers FIRST" If that doesn't slow the HR then look to Adenosine, but since the patient is obviously is symtomatic, the look of the patient gives you that, you need to go to direct cardoversion. First, Valium or Versed, your local protocols take affect, then shock. The use of "Amiodarone 150mg over 10 min., repeat x1" what does Ami do? It helps speed up the heart, exactly opposite of what your trying to do, slow do the heart.

Umm Wrong, Wrong and Wrong.

#1. This patient is alert and orientated with a stable BP, that means you try chemical cardioversion first.

#2. It is a WIDE complex tachycardia per the OP. Not a narrow complex or a complex of uncertain type. So vagal maneuvers and Adenosine are not called for.

#3. Amiodarone is an anti-arrhythmic it does not increase the rate of conduction. In fact it delays conduction by slowing repolarization. In other words in DOES NOT speed up the heart. Your thinking of an adrenergic like Epi or a parasympatholytic like Atropine.

[zzyzx]

The reason I posted this scenario was because I disagreed with what the authors were saying about the use of adenosine. I wanted to put it out there to see what other people have to say.

The other thing that should be addressed is whether this patient is really stable. AZEP wrote, "stable tachycardias afford the luxury of time." Although I'm always impressed by AZEP's knowledge and experience, I'm gonna have to respectfully disagree with him on this one. Yeah, stable SVT is no sweat, but is this guy stable? I don't believe that someone with WPW + AF is gonna be stable for long, and I don't think we have the luxury of time in that situation. I would expect him to deteriorate into VF pretty quickly. Anyway, considering how fast his heart rate is, it's very suprising that he is still able to compensate.

[AZCEP]

That is a common misconception that people like to throw around when they want to do something other than think the situation through. We are not judging this patient by the possibility/probability of deterioration of this rhythm. A good many patients will remain in an otherwise significant tachycardia for days/weeks with no issues.

Based on the information given in the scenario, he is not unstable. Being diaphoretic following a jog does not absolutely correlate with sympathetic discharge due to his heart rate. Either direction you decide to look at this from, you can be justified in thinking it.

devildoc0908,

This dysrhythmia is one that you should not do anything that will affect the AV nodal conduction. Even without seeing the rhythm, you should be able to determine what is happening based solely on the rate. This is the one time that it tells you enough to base a decision on.

A vagal maneuver, or adenosine will slow conduction through the AV node and precipitate VF in this patient. Beside the fact that neither are indicated for a "wide-complex tachycardia", why would you want to use either of them?

Amiodarone does not cause the heart rate to increase as Scaramedic noted. I hope you got your wires crossed and were thinking of something else. Amiodarone may take a while to show the effect you are after, but it will not speed the heart rate up. Even if it was possible to do so, this heart is going as fast as it is able to. Short of overdrive pacing, if you could get it that fast, you are not going to make it go any faster.

[devildoc0908]

Thanks, I did miss read it originally. So there for my inital assessment would have been off. The way I did it was the way I read it, if it was something else I would have done it similar to what you are stating. As far as Amiodarone, I have been using Epi for the past 10 years, so when you state Amiodarone can be given once in a 24 hour period for in ACLS, i was under the assumption that it was used to stimulate the heart to cause it to beat. If I am wrong then I am wrong and if so someone explain the correct correlation of Amiodarone and its use and used for.

[AZCEP]

Thanks, I did miss read it originally. So there for my inital assessment would have been off. The way I did it was the way I read it, if it was something else I would have done it similar to what you are stating.

Hopefully, you've had a chance to go back and reread the scenario that zzyxx presented to see where the misinterpretation came from.

As far as Amiodarone, I have been using Epi for the past 10 years, so when you state Amiodarone can be given once in a 24 hour period for in ACLS, i was under the assumption that it was used to stimulate the heart to cause it to beat.

Epinephrine has been the vasopressor of choice for the last 30+ years. It's clinical effectiveness has been under investigation for at least the last ten. Other agents are poised to take it's place. Epinephrine has never been used with the sole intent of "stimulating the heart". It's role in ECC has always been to provide peripheral vasoconstriction, and central vasodilation to allow for the "shunting" effect that we want. If you are teaching paramedic students, then you should already know that amiodarone is an antidysrhythmic. Your statement is akin to saying that because you use lidocaine after epinephrine, it too will stimulate the heart. Clearly, this is a misrepresentation of the drugs mechanism of action.

If I am wrong then I am wrong and if so someone explain the correct correlation of Amiodarone and its use and used for.

http://www.rxlist.com/cgi/generic/cordarone_iv.htm

There is a drug profile from Rx List.com. It should help you to fill in the gaps to better understand how amiodarone (Cordarone) is used.

[chbare]

I agree.

It seems there is still confusion regarding the patient's status. Remember, you can be symptomatic and remain stable. Symptomatic and unstable are not synonyms. In a patient with stable hemodynamics, intact neurological status, and minimal symptomology, why would we not consider a trial of medication?

With that said, I understand that some people will interpret the current guidelines differently.

In addition, I agree that a medication such as amiodarone would be a good choice for this type of tachycardia. I would also like to add that any medication that specifically targets the AV node such as adenosine should not be used in any patient where you suspect A-fib or A-flutter pre-excitation. I think the pathology behind the problems associated with this practice have already been discussed.

Take care,

chbare.

[zzyzx]

Do you guys understand what I'm getting at here? One the one hand we've got the smart people who wrote this article saying, "Don't use adenosine for WPW or wide-complex tachycardias." On the other hand we've got the drug manufacturer saying "Use adenosine for WPW." So who's right?

[AZCEP]

Ahhhhh, now I see the confusion.

The manufacturer is suggesting that for a re-entrant pathway tachycardia, adenosine is acceptable to use. Because WPW can be a reentrant mechanism, it would be reasonable to use. Without speaking for them directly, I would guess that they are referencing the possibility of other accessory pathway dependent rhythms that may not have a wide QRS complex associated.

WPW does not always widen the QRS complex, nor does LGL for example. In the event you decided to use adenosine the rhythm could convert to VF, which you would promptly defibrillate. This may not be the worst course of action, but if given the opportunity would you want to do this to a patient that isn't showing specific tachycardia related signs?

My thought is if treatment is needed for this situation use some sedation/analgesia, and cardiovert. Because the information provided presents a relatively stable patient, I'd be inclined to wait for more controlled circumstances.

...or at least let someone else screw it up :wink:

[chbare]

In addition, many people strongly caution against using adenosine when an underlying A-Fib or Flutter is present. With a rate of 310 and WPW, I will assume A-Fib until proven otherwise and avoid using adenosine.

Check out this reference for additional information: http://www.emedicine.com/emerg/topic644.htm

Take care,

chbare.