Rhythm Challenge #2

Here’s an interesting rhythm strip that was captured in the days before my EMS system had 12-lead ECG monitors.

What do you think?

*** Update 01/20/2010 ***

Here is the rhythm strip taken on arrival at the hospital.

Here is the 12-lead ECG that was captured at the hospital.

Does that change anything?


  • Squeezey says:

    Hmmm, quite a humdinger! I'm still at uni and have no other comments to go from so I'm sure my guess will be horribly off the mark, however I'm bound to learn from it!I think I've figured out where the baseline is, and the QRS looks wide, leading me to think that the rhythm is ventricular in origin. It looks as though there is ST depression, and perhaps a retrograde p wave suggesting a junctional rhythm, but it doesn't really fit with my ventricular origin theory. Will be interested to see what comes up!

  • Tom B says:

    Squeezey -Interesting guess! I certainly agree that the QRS is wide.Just as a side note, and not in reference to this rhythm strip specifically, both junctional and ventricular rhythms can show VA conduction (retrograde P-waves).Thanks for the comment!Tom

  • Squeezey says:

    Thanks for that Tom. Thought junctional rhythms could only be of an atrial nature, so thanks for the tip :)

  • Anonymous says:

    I too am only a lowly amateur when it comes to ecg interpreting.So here goes…I see enlarged P waves in there consistent with right atrial enlargement.I see ST depression also.Here endeth my guess!

  • Christopher says:

    Rules:- P-waves present, upright, peaked (p-pulmonale criteria met)- Regular save for 3rd complex- Rate 70-75- P-waves are associated- PRi is around normal 0.12- QRSd is wide (quite wide)Sinus rhythm with a bundle branch or abberant conduction.I'm concerned that it appears there is ST-depression or concordant T waves when there shouldn't be. I'm considering potassium changes as well (w/ such a significant QRSd). Obviously any rhythm like this gets a 12-L.

  • Scott says:

    Sinus @ ~ 80 w/ QRS widening …thinking hyperK

  • I'd also want a 12-lead to assess for BBB. This strip reminds me of a three lead where all the medics were scratching their heads looking at the monitor (thinking we mixed up the leads) until we did a 12-lead and it was like an "Ah hah!" moment (LBBB).

  • Anonymous says:

    It does make one wonder about hyperkalemia, though typically if the QRS is affected to this degree you have very small, if any, p-waves.

  • Tom B says:

    Anonymous – Right atrial enlargement is a fairly obscure finding for a lowly amateur! :)I can see where you would think that based on this ECG.Tom

  • Tom B says:

    @C.WatfordVery good point! Any rhythm like this needs a 12-lead ECG. It will be interesting to see how much the 12-lead changes (or confirms) your impressions! Tom

  • Tom B says:

    Scott -Awesome job calculating the rate! May I please know what method you used?Tom

  • Tom B says:

    MIFL – First of all, I always type MILF when I abbreviate your blogger profile name! :)I'm going to post the 12-lead ECG so you guys can see if it fits the pattern of a bundle branch block.Tom

  • Tom B says:

    Anonymous – You're absolutely correct with regard to the P-waves in the setting of hyperkalemia.I wonder if those are really P-waves…Tom

  • Hillis says:

    Not easy especially in the abscene of history and clinical presentation ..I will interpret the 3rd ECG it is quite difficult to judge ECG by one or 2 leads only.. So in the 3 rd ECG i can see atypical P wave wich indicate that the rythm is atrial , the PR interval is shorter, could it be WPW syndrome ?.The P wave is taller than normal , right atrial hypertrophy ??. There is sign of LBBB with the typical apperance of appropriate T wave discordance .

  • Sooo…maybe ask him what color his urine is? Assess the arm for shunts? Trying throwing a little albutrol, sodium bicarb and calcium chloride at him and see if that does anything?! :)If it really is hyperkalemia…I would be guessing it's reaching the unhappy place of around 10 mEq

  • Shane says:

    ? accelerated idioventricular rhythm

  • Mike says:

    Okay I posted about the p waves as anonymousRe: second strip–we're really working on getting to the sine wave stage!Re: third strip–those "p" waves very well may be part the widened QRS. They just look like p-waves. V1 is typically also a good lead to look for p-waves, and there's none there. Based on the change between the two rhythm strips, the lack of p waves and the non-specific and grossly prolonged non-specific intraventricular conduction delay, I would say this is almost certainly hyperkalemia. The rhythm is most likely sinus, the hyperkalemia has basically erased the visible p-waves (but really they are still there most likely). Next stop, sine wave and cardiac arrest. This patient doesn't need labs BEFORE treatment especially if there is a likely hx. Even without a dialysis or other likely hx, there is new-onset acute renal failure to consider.

  • Mike says:

    One other thing: looking more closely at strip 2. It looks like it shows a VTach alarm–with a heart rate of 71. Beware of slow VTach (120 bpm or less) especially when there is extreme QRS widening, because it usually isn't VTach. Consider: Hyperkalemia, TCA OD, Cocaine OD, accelerated idioventricular rhythm (typically a reperfusion dysrhythmia).If you weren't sure which of the above insults were causing the widening, what medication would you consider (that should help at least three of the four)?

  • TatonkaDTD says:

    I don't see p waves, so I'd call it an idioventricular rhythm unless the pt had a hx of a ventricular pacemaker.

  • Christopher says:

    12-L shows no P's in the leads I'd expect to see them the best in (namely V1). I read about the S5 lead from our friend the Ambulance Driver which can help look for atrial activity, but I think it's safe to say we have AIVR.QRSd of 0.204 screams high K. I'm worried about imminent arrest.

  • Mike says:

    Okay, it looks like AIVR, but if you treat it with Ca, Sodium Bicarb, Albuterol, Kayexalate, Insulin-glucose, dialysis—the p waves should gradually reappear in their usual location as the QRS gradually narrows. AIVR implies the rhythm is originating in the ventricles. I believe the actual source of the impulses is the SA node (or at least not the ventricles). The p waves are just so impacted by the hyperkalemia that they get smaller and smaller, until the disappear from the surface EKG.

  • Tom B says:

    Forgive me for not responding to each of you individually but it looks like you've got it pretty well figured out!This patient was indeed experiencing life-threatening hyperkalemia! You can see the entire story (including the lab values) HERE.@Mike – The question as to whether or not the sinus node continues to fire in severe hyperkalemia is an interesting one! I've researched it before and found mixed results.You also raise an excellent point about TCAs and other sodium channel blocking drugs having a very similar presentation! I'm very cautious when, 1.) the 12-lead ECG shows a nonspecific intraventricular conduction defect, or 2.) the QRS duration approaches 200 ms! If you have some time check out Dr. Smith's recent hyperkalemia examples HERE.Tom

  • Scott says:

    Tom, 300, 150, 100, 75 ….the original strip was just a touch to the left of the 75 block marker …so ~ 80.

  • Tom B says:

    Scott – That's cool. I was just curious because the patient's heart rate was exactly 80 the entire time we had him! I remember because I kept palpating his chest looking for a pacemaker!Tom

  • TatonkaDTD says:

    "I remember because I kept palpating his chest looking for a pacemaker!"At least I got one part right…

  • Tom B says:

    Tatonka -Yes, great minds think alike! :)Tom

  • Mike says:

    Here a couple of better explanations for why the P-wave gradually goes away, and then gradually reappears with treatment. I am interested in hearing about other theories."Hyperkalemia preferentially affects atrial tissue and suppresses the appearance of P-waves, even when sinus node activity is still present and activating the ventricle….When treatment is initiated, the P-waves seem to reappear. In reality, sinus activity was always present but simply not visible as P-waves." Amal Mattu, ECG's for the Emergency Physician 2"As the potassium level increases…the amplitude of the P waves decreases. Eventually you will not be able to see them. Why? As the potassium level increases, the atrial myocardial cells will stop depolarizing. The SA node and the special conduction system of the atria will continue to function but the myocardial cells will not. Because the atrial myocardium creates the atrial vectors as the P-waves, we do not see any atrial activity [P-waves] on the ECG." Garcia & Holtz, 12-lead ECG: The Art of Interpretation.

  • Mike says:

    Tom,I was also wondering if you would give your thoughts on this (from above) (assuming a critical patient with non-specific and progressively widening IVCD found down with no hx available and no dialysis access site, pill bottles, etc). I would think sodium bicarb as it would benefit hyperkalemia, TCA OD and Cocaine OD. Would it harm the pt in AIVR? I don't know.>> Consider: Hyperkalemia, TCA OD, Cocaine OD, accelerated idioventricular rhythm (typically a reperfusion dysrhythmia).If you weren't sure which of the above insults were causing the widening, what medication would you consider (that should help at least three of the four)?<<

  • Tom B says:

    Mike -Emergency treatment of suspected hyperkalemia from ACLS for Experienced Providers (2003) p.162.For moderate elevation (6 to 7 mEq/L):Initiate a temporary intracellular shift of potassium using the following agents:* Sodium bicarbonate: 50 mEq IV or up to 1 mEq/kg over 5 minutes* Glucose/insulin: Mix 10 U regular insulin and 25 g (50 mL of D50) glucose, and give IV over 10 to 15 minutes* Nebulized Albuterol: 5 to 20 mg over 15 min.For the periarrest patient, they recommend 10 mL of 10% calcium chloride IV over 2 to 5 minutes as the most important immediate therapy, and then the other therapies, along with diuretics and dialysis as required.In my service, we carry calcium gluconate.Tom

  • Tom B says:

    Mike -It's interesting that you quote Tomas Garcia MD for the "disappearing P-wave" theory. That's exactly where I first heard of it! Click HERE to read the post from the EKG Club.Tom

  • Medic-Minx says:

    I was thinking Hyper K+ almost immediately. The widening of the QRS along with slow merging of the T's into the QRS making it a borderline sinoventricular rhyhm…not quite the sine wave (ran a pt that labs came back 8.8 K+, & was in the pre-arrest sine wave of about 40-60 BPM) but pretty close. I wish more agencies pushed for fiekd Tx's of Hyper K+, we don't do it but have all the drugs except CA-gluconate (you're lucky if you do!) or insulin. My research has lead me to this being one of the few things you can Dx in the field from a 12-Lead only before labs are drawn. I'm fascinated with what the heart can & will do.

  • Adam Thompson, EMT-P says:

    Sine Wave/NSIVCD. Ca+ chloride/glauconate if you have it.

  • Medic-Minx,

    I actually think Calcium Chloride is the better option for EMS over Calcium Gluconate. CaCl makes a first pass thru the liver and thus can be given as an IV push without concern for the the side effects of rapid administration of CaGlu. CaGlu has to be done as a drip in order to avoid bradydysrhythmias or VF! All you need with CaCl is a good, patent line as its not so nice if it extravasates.

    The best usage for CaGlu in EMS would be for hydroflouric acid burns. It can be nebulized, injected SQ, or used in gel form on the skin.

  • David Baumrind says:

    Just to add, i believe Calcium Gluconate only has about 1/3 the calcium in strength as Calcium Chloride. Another reason i believe it is a better choice for EMS.

3 Trackbacks

Leave a Reply

Your email address will not be published. Required fields are marked *

EMS 12-Lead

Cardiac Rhythm Analysis, 12-Lead ECG Interpretation, Resuscitation

JEMS Talk: Google Hangout

Conclusion: 38 Year Old Male – Chest Pain and Leg Paralysis.
It was more informative if you did Chest X Ray for every patient with Chest pain .
2015-10-07 07:29:34
Darren Earley
Conclusion: 38 Year Old Male – Chest Pain and Leg Paralysis.
Ventricular pre excitation
2015-10-06 15:19:34
38 Year Old Male – Chest Pain and Leg Paralysis.
#3, drop BP, call chest cutter, fly pt. chest pain + neuro deficit= aortic dissection
2015-10-06 13:17:53
38 Year Old Male – Chest Pain and Leg Paralysis.
LVH with strain St depression in inf leads St elevation in avl ,v1 to v4 Here major problem is high B.P that causes focal neurological deficiet at the same time effect of hypertension on heart may results in st t changes but imp things here pain that's not responding so Aortic Disection also kept in…
2015-10-06 05:44:53
Darren Earley
38 Year Old Male – Chest Pain and Leg Paralysis.
Ventricular pre excitation.
2015-10-05 18:23:40

ECG Medical Training

12-Lead ECG Challenge Smartphone App


12-Lead ECG Challenge Smartphone App - $5.99

  • Apple iOS
  • Android
  • Amazon
  • Web Based

  • FRN-TV video review
  • iMedicalApps.com review
  • Interested in Resuscitation?

    Interested in Advanced Cardiac Life Support?

    FireEMS Blogs eNewsletter

    Sign-up to receive our free monthly eNewsletter

    Visitor Map / Stats

    Locations of visitors to this page