# Blocks, blocks and more blocks!



## emtbill (Jul 17, 2009)

You're dispatched to an 80 year old male patient who requests evaluation after being awoken from sleep with chest pains, but is currently asymptomatic. Upon arrival you find the patient ambulatory at the scene in no obvious distress. He states he was awoken about an hour prior to calling EMS with a sharp stabbing pain right in the center of his chest and it was difficult to breathe. He states he has taken 2x nitroglycerine tablets SL and 1x albuterol nebulizer over the past hour prior to your arrival. Currently he states his pain is dull rather than sharp and he is still moderately short of breath, but no real difference from baseline. Your physical assessment is unremarkable except for slight expiratory wheezing upon chest auscultation. Initial set of vitals are all WNL except that SpO2=91% on room air, but the patient states this is normal for him. The patient states he had an MI "years ago" and does have COPD but is unable to provide you with a better medical history than that. Patient states he feels fine but was worried that his pain was significant to awaken him.

He agrees to transport and further evaluation. You load him into the truck and start supplemental oxygen and a peripheral IV line. You obtain the 12 lead as attached. The computerized interpretation says the heart rate is 97 bpm, PR interval is 216, QRS duration is 140, the QTc is 508, and the QRS axis is -88. You begin transport and administer ASA and NTG en route with no change in patient's condition, vital signs, or EKG.

What is your interpretation of this EKG? How would this change your treatment of the patient if his condition were to worsen? His ventricular ectopy continues at the same rate and morphology as shown in the six second strip throughout transport.


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## emtbill (Jul 18, 2009)

No takers? What would you do if this patient went into sustained VT, knowing what you know with this 12 lead?


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## boingo (Jul 19, 2009)

Looks like a NSR at about 90 with RBBB and LAFB and occasional unifocal PVC's.  If the patient went into a sustained VT I'd either cardiovert or if stable Amiodorone over 10 minutes.


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## MrBrown (Jul 19, 2009)

I don't trust the computer analysis (it's helpful) but I perfer to manually look at the strip too! 

Regular sinus rhythm of about 100 (1500 method), I do see what looks like an RBBB (rabbits ears) but I'm not seeing any PVCs .... 

If his condition were to worsen but the strip remained the same I'd give him another .8 of GTN provided his BP was > 100 systolic.  Should his pain become consistently intolerable and we could be located by an Officer able to give morphine (Upskill or Advanced Paramedic) significantly faster than we could deliver the patient to hospital I'd call for backup. 

WRT to this pt developing VT, if the VT was well tolerated and not compromising then we would transport with no specific treatment.  If the patient developed a compromising VT or arrested we'd call for an Advanced Paramedic capable of administering amiodarone and pain relief for cardioversion .

At the AO level we can cardiovert but not give pain relief; which doesn't sound like much fun!!


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## emtbill (Jul 19, 2009)

What about a primary AVB in addition to the RBBB and LAFB? Would you want to give lidocaine or amiodorone in a bifascicular block?


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## MrBrown (Jul 19, 2009)

Are you talking a ventricular arrythmia in addition to a bundle branch block or AVB with a BBB?  I'll have to look deeper into that one.

For just a bundle branch block or any degree of AV block then no that's not what amiodarone is for!


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## emtbill (Jul 20, 2009)

MrBrown said:


> Are you talking a ventricular arrythmia in addition to a bundle branch block or AVB with a BBB?  I'll have to look deeper into that one.
> 
> For just a bundle branch block or any degree of AV block then no that's not what amiodarone is for!



I'm saying this patient currently has blocks in the AV node, right bundle branch, and left anterior hemifacial. If his ventricular ectopy worsened to sustained VT do you think it would be a good idea to give drugs that will further inhibit the conduction system knowing he has these blocks? Probably not. It would be a better idea to sedate and cardiovert so you don't throw the patient into asystole. I thought this would be an interesting case to present as it shows the importance of ALS providers knowing how to read a 12 lead before giving any cardiac drug. If you were just working out of lead II you can only see the AVB, and if you were to treat the PVC's or runs of VT based on lead II you would probably do the patient more harm than good knowing what you know form the 12 lead.

Incidentally, if this patient were to receive lidocaine or amiodorone and then went into asystole I think TCP would be a good idea. ACLS always says not to pace asystole but if you think outside of the box and realize that this patient's conduction system is dead but that his myocardium is fine, pacing would probably save him while the drugs wear off.

What do you think?


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## MrBrown (Jul 20, 2009)

I think you just answered your own question ^_^

Amiodarone or lidocaine (or for that matter any ventricular antiarrythmatic) is not a good idea as you are liable to wipe out any ectopic foci which are acting as a pacemaker and as you say, throw him into asystole.

This is a very interesting scenario; I'll take it down to the station next time and give them Lead II and see what they come up with.

I do however have one question .... why are all the complexes inverted?


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## emtbill (Jul 20, 2009)

I don't really know what you mean by inverted complexes. Remember that positive and negative deflections are made from the isoelectric line based on whether depolarization is occuring toward or away from the positive electrode of the lead (an upward complex is made going towards the positive electrode and vice versa). These complexes are abnormal because the blocks in the electrical system force the electricity to be conducted around the block, which results in different complexes seen in a normal system where impulses travel straight down from the SA node to the ventricles in a linear fashion.


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## MrBrown (Jul 20, 2009)

emtbill said:


> I don't really know what you mean by inverted complexes. Remember that positive and negative deflections are made from the isoelectric line based on whether depolarization is occuring toward or away from the positive electrode of the lead (an upward complex is made going towards the positive electrode and vice versa). These complexes are abnormal because the blocks in the electrical system force the electricity to be conducted around the block, which results in different complexes seen in a normal system where impulses travel straight down from the SA node to the ventricles in a linear fashion.



Thanks!; I'm not up-to "offically" interpreting a 12 lead yet so haven't covered bundle branch blocks.


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## mycrofft (Jul 21, 2009)

*AN inverted wave IS one travelling the "wrong" direction.*

Both right, hand out the stars and break for Cornish pasties and brew.


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