Clinical Case 049: the Unseen ECG

I was sitting at the desk writing up some notes when the triage nurse stuck the following ECG strip under my nose.

The story was that this chap was a hypertensive, obese, diabetic vasculopath with impaired renal function who had presented with a fever of 39 deg and nasty looking diabetic feet (see Clinical case 047 for example…).  He was looking unwell so she did an ECG on the off chance he might be having a silent infarction.

So here we are – sick looking, high-risk sounding patient.

No chest pain; No previous IHD documented; Previous ECGs? – he had a normal exercise stress test 2 years ago with a normal baseline ECG in the chart

OK, all you smart ED types.  Can you make the diagnosis?  What is going on here?  There might be a trick or two …..

Ok a few observant comentators noted the machine was running at 50mm/sec – and the V leads were missing. The patient was running at 126 bpm clinically and on the monitor. Unfortunately our new nurse who was not familiar with the machine pushed the wrong buttons and gave me a terrifying minute or two as I made my way to the bedside! The penny eventually dropped and I could breathe a big sigh of relief!. The true ECG showed a tachy @ 126 with a RBBB pattern and no convincing P waves. So channeling Chris Watford (Emcrit) I did a Lewis lead config – and the P-waves popped up like they should! Sweet – we were back to boring old sinus tachy in a septic patient and all was well!

1. Always look at the patient before the ECG, or at least shortly thereafter!

2. If something doesn’t add up, check the basics, repeat the test and ask, ask, ask

3. Septic patients can develop nasty arrythmias – SVT, AF, transient heart blocks (RBBB), VT etc – so beware the sepsis with tachy, find those P-waves – as all the other options are not good for their cardiac output.

4. Lewis leads (S5) actually works, it is cheap, easy and makes you look smarter!



  1. LMCA occlusion?

    • Palpitations cannot show on an ECG. AN ECG will show you the elraceictl activity but palpitations are something you feel.If you had palpitations and your ECG is normal it just means you are one of those people who is more aware of their heart beat. Most of us only feel out heart beat after exercise or if there is a really fast heart rate but some people can feel it all the time -sounds like you are one of them.

  2. Well I guess I should say how about a little history and a physical, but while we’re talking can I get a K+, and a bedside echo?

  3. Casey Parker says

    Nice call Seth…. but no, no cigar. Not LMCA blocked. Look a little closer, or stand back a bit – whatever works! Casey

  4. Casey Parker says

    Mike. History and physical come after US. Nothing to say other than he looks sick. K+ is 4, normal.
    ECHO ( by me) LV is clapping along and walls almost kissing, no obvious RWMA. Hyperdynamic LV, flat collapsing IVC. Improves with 2 L of fluid.
    Lactate is 3.5 mmol if you care to know
    There is a trick…..

  5. It wouldn’t hurt to see the other leads but it’s a regular rythm with some takycardia. P-waves are small which makes it a bit tricky but I’m wondering if there’s a 2:1 blocked flutter (either look on the HR-trend on them monitor or lewis lead/esofageal lead to rule the flutter in/out). I’ll leave the rest of the interpretation until I get the other leads.

  6. marco anzini says

    50 mm/s..

  7. The strip is running at double speed…

  8. Two questions to help clarify the situation:
    1. Do you have V-leads to show us?
    2. Does your facility commonly use 50mm/sec tracings?

  9. Patrick Linehan says

    50 mm/s?

  10. Why at 50mm/sec?

  11. minh le cong says

    can we have a lewis lead please? rates a bit variable but not what computer calculated

  12. minh le cong says

    medication list ..? digoxin
    can I have the other ECG leads , V6…this looks like LBBB
    funny RhYthm, looks junctional
    previous normal ECG…the guy sounds septic.. suggest new LBBB prob ischaemic related but how recent? Echo suggests old Event given no obvious RWMA
    fluid responsive so treat for sepsis and do serial troponins. admit patient for sepsis

  13. Where’s the rest of the leads!

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