Without evidence of benefit, an intervention should not be presumed to be beneficial or safe.

- Rogue Medic

EMS 12 Lead Bradycardia Post – Part II

Continuing from Part I.

This is the rest of the discussion of 82 year old male CC: Shortness of breath and 82 year old male CC: Shortness of breath – Conclusion.

Here is the 12 lead again. –

I made it a little larger, because I expect that you have already looked at it, and the other ECGs from this patient, in Tom’s post.

The first thing I notice about this 12 lead is that there are only 2 clear QRS complexes in 10 seconds.

If the heart is beating, where is the current in the leads being recorded?

This is a 12 lead. Each portion of the printout is the simultaneous recording of 3 different leads. If there is current it should show up in the other 2 leads in the same section of the 12 lead. It could be that the axis is perpendicular to that lead, but again there are 3 leads, so the axis cannot be perpendicular to all three of the leads simultaneously recorded.[1] The first 12 lead did show Low voltage QRS in the analysis, but it also did show what appear to be QRS complexes in all of the leads.

At 07:44:31 12 lead 1 is recorded with apparent QRS complexes in all leads.

At 08:01:44 12 lead 2 is recorded, but only half of the 12 leads appear to have QRS complexes.

15 minutes later and the ECG looks worse.

The patient is sweaty/clammy/diaphoretic. Whatever terminology we use, the patient is wet. Wet is the enemy of having the leads stick, although wet is an important part of the means of conduction of the electricity to the monitor. How do we quickly troubleshoot our equipment?

Check the pulse.

Is the patient’s heart rate really only 2 beats every 10 seconds?

If yes, that means a heart rate of about 12 beats per minute. The rhythm is irregular and this is a very small sample, but the important point is that a heart rate of 12 in a human is incompatible with survival.

Even extreme athletes do not get their resting heart rates below the 20s and this 82 year old hypertensive diabetic is not an extreme athlete. He is extremely unstable. Another possible explanation would be if the person were hypothermic, but there is nothing in this case presentation to suggest hypothermia.

Tom makes some important points about the way to approach an arrhythmia. One is the potentially reversible causes. This patient is not yet in cardiac arrest, but by treating the potentially reversible condition that is expected to progress to cardiac arrest, perhaps we can prevent a cardiac arrest.

What is the potentially reversible condition?


Consider this conversation between Stephen Smith, M.D. (from Dr. Smith’s ECG Blog) and Scott Weingart, M.D. on the EMCrit podcast:

SW: “I know I’ve learned from being burned many times, that when I have a profound bradycardia or heart block, as my residents are getting excited to place in a pacer, even if the patient has no preexisting history, I do a trial of calcium chloride or calcium gluconate because I’ve just had so many cases where it turned out to be hyperkalemia. Is that your experience as well?”

SS: “That is my experience as well and I think it’s very wise you’re giving calcium before you start pacing. By far, more common than intrinsic causes of bradycardia and heart block is hyperkalemia — so common — and so frequently overlooked. It’s a great imitator, I think. There are so many ways the ECG can manifest with severe hyperkalemia — life-threatening hyperkalemia. Again, the treatment is benign, and cheap! So how many life-threatening diseases can you treat benignly and cheaply?”[2]

SW is Scott Weingart, M.D. SS is Stephen Smith, M.D.

While calcium is not generally in EMS protocols for bradycardia, we should consider these critical statements by Dr. Smith –


I think it’s very wise you’re giving calcium before you start pacing.




Again, the treatment is benign, and cheap!


A lot of people do not seem to be familiar with the word benign.


1. kindly: having a kind and gentle disposition or appearance

2. not life-threatening: not a threat to life or long-term health, especially by being noncancerous
a benign tumor

3. harmless: neutral or harmless in its effect or influence

4. favorable: mild or favorable in effect
a benign climate

[14th century. Via French< Latin benignus]

be·nign·ly adverb[3]

What if the low amplitude/no amplitude of the QRS complexes the 12 lead claims are there really are there? Would that be an indication of hypokalemia?


The beats that are clearly present are not giving any indication that the patient is hypokalemic.

The beats that I do not see, but the 12 lead counts are probably not there, but definitely not being hidden by hypokalemia.

Why does the machine come up with a different heart rate from what I come up with?

The machine could be wrong.

I could be wrong.

Both of us could be wrong.

The best way to assess this is to actually touch the patient and assess for the presence of a palpable pulse.

It is interesting that the 12 lead does not make any suggestion about considering hyperkalemia, while the doctors think that unstable bradycardia is a good reason to automatically treat for hyperkalemia.

What is important about this case?

We need to anticipate the patients with unstable bradycardia.

We need to have some sort of plan for what to do with the bradycardia patient who is mostly dead.

We need to discuss this with medical directors ahead of time, so that this does not become a long conversation on a command line while the patient expires or a conversation that ends with an order to Just transport.


[1] Axis Determination – Part I
EMS 12 Lead

Tom continues this in Part II, Part III, Part IV, Part V, and Part VI.

This will tell you all you need to know about axis (which is very important) and it should explain better what I am trying to point out. If we understand axis and amplitude, this should be something that immediately gets our attention.

[2] EMCrit Podcast 42: A phD in EKG with Steve Smith

The supplementary material covers 10 points covered in the podcast, including –

8. If you see a wide (>190 ms) QRS, think Hyperkalemia


9. The treatment for VT with hyper-K is Calcium, Calcium, Calcium

Dr. Smith’s EKG Blog

[3] Benign



  1. If you’re carrying Calcium Chloride you need to be very comfortable with the patency of your IV/IO access. Extravasation of CaCl is on par with dextrose.

    Otherwise, yes it is benign.