Treatment of high 2º heart block and 3º heart block

[RomeViking09]

In paramedic school and reviewing from cardiology that ended a few weeks back, If you are dealing with a bradycardic 2º type II or 3º AV block that requires treatment (poor perfusion, ALOC, etc...) do you attempt to use atropine first are are you reaching for the pacer off the bat? Reason I ask is in a study group we found mixed things in articles online and even in our textbook. My view is that high degree 2º and 3º AV block are past the point that the atropine is going to work, yet some articles are saying to still attempt 1mg IVP (for adults) prior to attempting to pace the patient. What to get some other student views and those who are working on the streets.

[Inf]

Well if the heart block is due to an acute MI, then Atropine will worsen things by unopposed sympathetic stimulation, irritating the ventricles into SVT, VF, or VT, not to mention increased oxygen demand by the heart which could lead to further ischemia. For 3rd degree block the blockage is usually below the AV node, so Atropine will not be beneficial, not to mention the side effects that are associated with Atropine.

Personally, with "BP at 62/P, HR at 44, RR 10 with poor chest rise, PT is Altered LOC" I would have my partner assist ventilations with BVM and supplimental O2, start an IV, consider sedation with Etomidate and go straight for transcutaneous pacing.

On the other hand, if you have a patient with BP of 80-90, HR 40-50 and symptomatic 1st degree block or 2nd type I block, then 0.5 mg Atropine rapid IV bolus might be beneficial, again provided that there is no suspicion of MI after you've done a thorough clinical assessment and 12-lead EKG.

Slow heart rate and low blood pressure are not necessarily going to kill the patient. I've seen a patient with HR of 30 and BP of 40/20 who was well oxygenated and responsive to voice stimuli, with her eyes open

Edited August 31, 2010 by Inf

[Kiwiology]

I would try but if it doesnt respond to a good dose or two of atropine its time to move in to pacing

[Doczilla]

I do it. First off, I don't buy the argument that it will increase myocardial oxygen demand through unopposed sympathetic stimulation. The heart rate is TOO LOW, so you're not going to have a runaway heart rate that will extend the infarct. We use dopamine and dobutamine all the time for this sort of thing without concern for extending the infarct. The best thing you can do for the infarcting heart is improve the supply. Second, a patient with a high degree AVB due to digoxin may benefit from atropine. AVB from dig is parasympathetically mediated through increased receptor sensitivity, increased PS transmission at the AV node, and direct PS stimulation. It is not going to cause harm in the emergency setting, takes no time to do, and is a lot less painful than pacing.

'zilla

[chbare]

I do it. First off, I don't buy the argument that it will increase myocardial oxygen demand through unopposed sympathetic stimulation. The heart rate is TOO LOW, so you're not going to have a runaway heart rate that will extend the infarct. We use dopamine and dobutamine all the time for this sort of thing without concern for extending the infarct. The best thing you can do for the infarcting heart is improve the supply. Second, a patient with a high degree AVB due to digoxin may benefit from atropine. AVB from dig is parasympathetically mediated through increased receptor sensitivity, increased PS transmission at the AV node, and direct PS stimulation. It is not going to cause harm in the emergency setting, takes no time to do, and is a lot less painful than pacing.

'zilla

Absolutely agree, why not administer atropine while setting up to pace? If it works, good deal, if not you have pacing available.

Take care,

chbare.

[Just Plain Ruff]

Absolutely agree, why not administer atropine while setting up to pace? If it works, good deal, if not you have pacing available.

Take care,

chbare.

I totally agree with CH and Doc

Electricity has it's place but I have always been of the opinion that chemical rather than electrical.

If they need electricity then by golly they are going to get it but like doc says, it's not going to cause harm in the emergency setting. If it doesn't work then pace them.

but why not use one of your tried and true tools that does not hurt before you go and start to jolt em with electricity.

If the atropine doesn't work what time did it cost you? Just the time to administer it and wait a couple of minutes to see if the effects are going to work. while you are waiting for atropine to work or not, you can be drawing up the valium or ativan and putting pacer pads on the patient's chest.

If it works and keeps working then you've saved the patient from getting 60 jolts a minute for a 10-20 minute ambulance ride.

I go for atropine first unless the patient is so critical that they can't wait and pacing is immediately needed.

[fiznat]

The vagus nerve innervates the heart at the SA and the AV nodes, which is why atropine is generally contraindicated in high degree heart blocks. Increasing the rate of the atria is not going to effect the ventricles if you've got a distal block along that line of conduction. Anticholinergics aren't going to "unblock" a node. That said, cardiac conduction (and it's pathology) is complicated and dynamic. Even though it makes sense that a distal block would undermine atropine's effect, it doesn't mean it will *never* work with a high degree block. I've seen it work, in fact. I think what Doczilla (and others) suggested is right on. If you've got the extra hands and the time to trial a dose of atropine WHILE you are setting up the pacer (which is the clear-cut ACLS answer to your question, by the way: pace immediately), I don't see anything wrong with that.

[JakeEMTP]

I think what Doczilla (and others) suggested is right on. If you've got the extra hands and the time to trial a dose of atropine WHILE you are setting up the pacer (which is the clear-cut ACLS answer to your question, by the way: pace immediately), I don't see anything wrong with that.

I also agree with the good Doczilla. I actually failed a scenario test at a Fire Dept. for doing it . They offered me a position anyway but I declined. I didn't think it was a good fit for me.

[RomeViking09]

Thanks for the input thus far, I know the cut dry ACLS answer is pace ASAP, but the debate was over atropine while setting up the pacer in the study group. Thanks for the help.

[Kiwiology]

Thanks for the input thus far, I know the cut dry ACLS answer is pace ASAP, but the debate was over atropine while setting up the pacer in the study group. Thanks for the help.

Real life is often not able to be taught adequately in a two day weekend workshop or placed into a standardised, no thinking required, see and do format for barely trained Houston Firefighters