Category Archives: ECG of the Week

05.24.13
by

ECG of the Week – 27th May 2013

This rhythm strip is from a mid forties male who presented following an episode of syncope.
He complains of nausea and dizziness on arrival to the ED.
Whilst being assessed he has an episode of unresponsiveness, the rhythm strip below was taken during this period.




Click to enlarge
Paper speed 25mm/s
VAQ Corner


This rhythm strip is from a mid forties male who presented following an episode of syncope.
He complains of nausea and dizziness on arrival to the ED.
Whilst being assessed he has an episode of unresponsiveness, the rhythm strip below was taken during this period.

a) Describe & interpret his ECG (50%)
b) Outline your management (50%)
05.22.13
by

ECG of the Week – 20th May 2013 – Interpretation


This ECG is from a 64 year old male. 
Presented following multiple episodes of syncope.




Click to enlarge

Rate:
  • ~42 bpm mean ventricular rate
Rhythm:
  • Irregular
  • Junctional escape rhythm 
    • Complexes number 1, 3, 4, 5
    • Rate ~ 36 bpm
  • Sinus 
    • Complexes number 2, 6, 7
Axis:
  • Normal (~70 deg)
Intervals:
  • PR - Upper limit normal where present (~200ms)
  • QRS - Normal (100ms)
  • QT - 520ms
Segments:

  • ST Sagging leads II,III,aVF,V5-6

Additional:
  • T wave notching in leads V1-3 in 5th complex likely secondary to lead transition
  • Biphasic T wave V1
  • P waves broad & notched
Interpretation:
  • Intermittent sinus arrest with junctional escape rhythm

What happened ?

This ECG was captured during a symptomatic episode of presyncope. 
The patient then spontaneously reverted to sinus rhythm after a few minutes.
His beta-blocker was ceased and he was transferred for PPM insertion.

VAQ Corner

A 64 year old male presents to your ED following an episode of syncope.
He complains of feeling lighted. 
BP 105/60 RR 18 Sats 96% Room Air

a) Describe & interpret his ECG (50%)
b) Outline your management (50%)

References / Further Reading

Life in the Fast Lane
  • Sinoatrial exit block here
  • Sick Sinus Syndrome here
Textbook
  • Chan TC, Brady WJ, Harrigan RA, Ornato JP, Rosen P. ECG in Emergency Medicine and Acute Care. Elsevier Mosby 2005.
05.17.13
by

ECG of the Week – 20th May 2013

This ECG is from a 64 year old male. 
Presented following multiple episodes of syncope.




Click to enlarge

VAQ Corner

A 64 year old male presents to your ED following an episode of syncope.
He complains of feeling lighted. 
BP 105/60 RR 18 Sats 96% Room Air

a) Describe & interpret his ECG (50%)
b) Outline your management (50%)
05.15.13
by

ECG of the Week – 13th May 2013 – Interpretation


This ECG is from a 23 year old female presenting with epigastric pain.






Click to enlarge

Rate:
  • 78 bpm (average rate)
Rhythm:
  • Two distinct rhythms
  • Sinus rhythm
    • Complexes 1-3, 9-12
    • Sinus arrhythmia
    • Rate varies 70 - 100 bpm
  • Junctional rhythm
    • Complexes 4-8,13
    • Rate ~70 bpm
Axis:
  • Normal
Intervals:
  • Sinus Complexes
    • PR - Normal (140ms)
    • QRS - Normal (60ms)
    • QT - 360ms (QTc Bazette ~ 450 ms)
  • Junctional Complexes
    • QRS - Normal (60ms)
    • QT - 360ms (QTc Bazette ~ 395 ms)
Additonal:
  • Nil T wave or ST segment changes

Interpretation:

  • Alternating sinus rhythm and accelerated junctional rhythm
As many of the comments have alluded to it is unlikely this is directly related to our patient's presentation - abdominal pain in a young female.
Junctional rhythms are reasonably common in young patients under general anaesthetic and rarely require intervention.
The case in this patient is a bit of a mystery, we don't see sinus slowing prior to rhythm changes although excessive vagal tone secondary to pain could be a culprit.

We have had a flurry of comments on this post, including a discussion on energy drinks and the risk of sudden cardiac death. I'd advise people to have a look through these comments which can be found on this page, scroll to the bottom. 

Also don't forget to check out the Google ECG+ Community where there are a host of interesting ECG's and ECG discussions.

VAQ Corner

A 23 year old female presents to your ED complaining over several hours of epigastric pain.
Her obs are normal and stable. An ECG has been performed.

a) Describe & interpret her ECG (70%)
b) Briefly outline your management of the patient (30%)

In this patient with normal vital signs the rhythm change does not require specific intervention and management should focus on symptomatic treatment e.g. pain, nausea, etc, and identification and subsequent treatment of underlying cause of abdominal pain.

References / Further Reading

Life in the Fast Lane
  • Junctional Rhythm here
Anaesthesia UK
  • Junctional Rhythm here
Textbook
  • Chan TC, Brady WJ, Harrigan RA, Ornato JP, Rosen P. ECG in Emergency Medicine and Acute Care. Elsevier Mosby 2005.
05.10.13
by

ECG of the Week – 13th May 2013

This ECG is from a 23 year old female presenting with epigastric pain.




Click to enlarge


VAQ Corner

A 23 year old female presents to your ED complaining over several hours of epigastric pain.
Her obs are normal and stable. An ECG has been performed.

a) Describe & interpret her ECG (70%)
b) Briefly outline your management of the patient (30%)
05.08.13
by

ECG of the Week – 6th May 2013 – Interpretation


I don't have any clinical information on this case unfortunately but it looks like an interesting ECG :-)









Rate:
  • Overall rate 60 bpm
Rhythm:
  • Irregular - likely regularly irregular
  • Pattern of 2 sinus complexes followed by 2 ventricular complexes
Axis:
  • Indeterminate
Intervals:
  • Sinus complexes
    • PR - Normal ( 160ms)
    • QRS - Prolonged (120ms)
    • QT - 400ms (QTc Bazette ~ 430 ms)
  • Ventricular complexes
    • QRS - Prolonged (180ms)
    • QT - 480ms 
Segments:
  • ST Elevation V2-4 of sinus complexes discordant to QRS
  • Discordant ST & T wave changes of ventricular complexes
Additional:
  • Notching in terminal portion of 1st ventricular complexes 
    • Best seen in lead II
    • Corresponds to atrial activity at a rate of 55 bpm
  • Regularly irregular atrial activity in pattern of 3 complexes then pause
  • Poor R wave progression
Interpretation:

  • Sinus rhythm
  • Intraventricular conduction delay
  • Regular coupled ventricular ectopics
Without more clinical information it's hard to comment further on the likely causes for this ECG appearance but some potential culprits are:

  • Ischaemia
  • Electrolyte / acid base disturbance
  • Drugs
    • esp. digoxin
  • Environmental e.g. hypothermia


VAQ Corner

For those planning to sit the ACEM Fellowship, or any of our other interested readers.
 I don't know anything about the real case so I've made up the clinical details for this question.

A 76 yr old female presents to your ED following a collapse at home. 
She complains of feeling dizzy and lethargic for the last 2 days.
She has a history of IHD, CCF, and hypertension.
She is on multiple medications but can not recall them.
Observations: BP 85/45 RR 16 Sats 95% RA GCS 14 (M=6 V=5 E=3)

a) Describe & interpret the ECG (50%)
b) Outline your management (50%)


I won't directly be answering our VAQ corner questions on the blog, unless it's a 100% describe and interpret. These questions are designed to give people the oppurtunity to think about the ECG with some clinical context, especially when I don't have a real case to attach to, and also to provide a chance to do some VAQ practice. 
If people would like to submit some answers I will happily added them to our posts, just email them to me here.

References / Further Reading

Life in the Fast Lane
Textbook
  • Chan TC, Brady WJ, Harrigan RA, Ornato JP, Rosen P. ECG in Emergency Medicine and Acute Care. Elsevier Mosby 2005.
05.03.13
by

ECG of the Week – 6th May 2013

I don't have any clinical information on this case unfortunately but it looks like an interesting ECG :-)








ECG of the Week VAQ Corner

For those planning to sit the ACEM Fellowship, or any of our other interested readers.
 I don't know anything about the real case so I've made up the clinical details for this question.

A 76 yr old female presents to your ED following a collapse at home. 
She complains of feeling dizzy and lethargic for the last 2 days.
She has a history of IHD, CCF, and hypertension.
She is on multiple medications but can not recall them.
Observations: BP 85/45 RR 16 Sats 95% RA GCS 14 (M=6 V=5 E=3)

a) Describe & interpret the ECG (50%)
b) Outline your management (50%)

I appreciate this is probably a long question in terms of VAQ format but it's nice to think about what would you do with the patient in light of the ECG.
05.01.13
by

ECG of the Week – 29th April 2013 – Interpretation


This ECG is from a 47 year old female presenting with palpitations of 3 hours duration.




Click to enlarge

Rate:
  • 156 bpm mean rate
    • Varies between ~135 - 185 bpm
Rhythm:
  • Irregularly irregular
  • Nil p waves
Axis:
  • Normal (+45 deg)
Intervals:
  • PR - Nil p waves visible
  • QRS - Normal (60-80 ms)
  • QT - 240-280ms (QTc Bazette ~ 360-470 ms)
Segments:
  • ST Elevation lead aVR (1mm)
  • ST Depression leads I, II, III, aVF, V4-6
Interpretation:
  • Atrial Fibrillation with rapid ventricular response
    • a.k.a 'Fast AF'
    • Inferolateral ischaemic changes
      • ? Rate related
VAQ Corner

Our VAQ style question for this ECG was :

47 year old female presents complaining of palpitations onset 3 hours age. She denies chest pain and is not short of breath. She has no prior medical history. Blood pressure is 120/75.

Her ECG is above.

a) Describe and interpret her ECG (30%)
b) Outline your management options (70%)

Management Options in Atrial Fibrillation

There are several considerations in the management of AF which include:

  • Rate vs. rhythm control
    • Electrical vs Chemical rhythm control
  • Anti-coagulation
    • Risk vs Benefit
    • Drug to use
  • ? Underlying precipitant
    • Infection / ischaemia / structural / endocrine / metabolic etc.
  • Follow-up / disposition
  • Ablation suitability

Despite being one of the commonest arrhythmia encountered in medicine there is considerable variability in the clinical management of atrial fibrillation. There are a number of international guidelines and protocols regarding AF management, including:


AF Related Calculators (links to MDCalc)



References / Further Reading

Life in the Fast Lane
  • Atrial Fibrillation here
Textbook
  • Chan TC, Brady WJ, Harrigan RA, Ornato JP, Rosen P. ECG in Emergency Medicine and Acute Care. Elsevier Mosby 2005.
04.26.13
by

ECG of the Week – 29th April 2013

This ECG is from a 47 year old female presenting with palpitations of 3 hours duration.




Click to enlarge


I'm coming up to my ACEM Fellowship exam later on this year and as part of my exam practice I'm trying to consider the ECG of the Week in a VAQ format.

With this in mind I'll be adding an exam style question with each ECG of the Week from now on for people to consider. I won't be directly answering these questions on the blog but hope they give a different spin on how our reader's can use the blog and our ECG's. For those of you not coming up to exams it might just be a bit of fun :-) 

Question:

47 year old female presents complaining of palpitations onset 3 hours age. She denies chest pain and is not short of breath. She has no prior medical history. Blood pressure is 120/75.

Her ECG is above.

a) Describe and interpret her ECG (30%)
b) Outline your management options (70%)
04.24.13
by

ECG of the Week – 22nd April 2013 – Interpretation


This ECG is from a 78 yr old male who presented with a 2 day history of lethargy and dizziness

He has a history of ischaemic heart disease, type 2 DM, hypertension, and chronic renal failure. 
Medications include calcium-channel blocker, beta-blocker, and ACE-inhibitor.

Conscious with systolic BP of 70 !





Click to enlarge


Rate:
  • ~42
Rhythm:
  • Regularly irregular 
    • Complexes occurring in paired group
  • Flat baseline without atrial activity

Axis:
  • 1st Complex in pair
    • Normal (70 deg)
  • 2nd Complex in pair
    • LAD(-45 deg)
Intervals:
  • 1st Complex in pair
    • QRS - Normal (80ms)
    • QT - 520ms
  • 2nd Complex in pair
    • QRS - Normal in limb leads, Prolonged V1-3 (80-120ms)
    • QT - 440ms
Segments:

  • 1st Complex in pair
    • ST Depression leads II, aVF
  • 2nd Complex in pair
    • Minimal ST elevation lead aVR

Additional:

  • 1st Complex in pair
    • T wave inversion II, III, aVF
    • Biphasic T lead V3
  • 2nd Complex in pair
    • RsR' Morphology V1-3
    • Inverted notching terminal portion QRS II, III, aVF also positive notching aVL
      • ? Retrograde P waves ? Secondary to conduction delay

Interpretation:

  • Escape bigeminy
    • In setting of sinus arrest / sinus exit block
  • Non-specific ST / T wave changes
Differential of causes:
  • Ischaemia
  • Electrolyte disturbance
  • Acid-base disturbance
  • Cardiotoxic drugs
  • Sinus node dysfunction
  • Hypothermia
    • Multifactorial combination of above


What happened ?

Bloods showed:
  • Acute on chronic renal failure
  • Metabolic acidosis - pH 7.0 Bicarb 7.0
  • K 6.0
Tx with isoprenaline, sodium bicarb, cessation of cardiotoxic medication, and dialysis.

Following acute episode found to have sinus pauses on telemetry necessitating pacemaker insertion.

References / Further Reading

Life in the Fast Lane
  • Sinus Arrest here
  • Sinoatrial exit block here
Textbook
  • Chan TC, Brady WJ, Harrigan RA, Ornato JP, Rosen P. ECG in Emergency Medicine and Acute Care. Elsevier Mosby 2005.
04.19.13
by

ECG of the Week – 22nd April 2013

This ECG is from a 78 yr old male who presented with a 2 day history of lethargy and dizziness

He has a history of ischaemic heart disease, type 2 DM, hypertension, and chronic renal failure. 
Medications include calcium-channel blocker, beta-blocker, and ACE-inhibitor.

Conscious with systolic BP of 70 !





Click to enlarge

04.17.13
by

ECG of the Week – 15th April 2013 – Interpretation

This week's ECG is from a 52 year old male.

Pt has a history of congestive cardiac failure, hypertension, hypercholesterolaemia and previous atrial flutter. 

Presented with palpitations with no chest pain or SOB when this ECG was taken.




Click to enlarge

Rate:
  • Ventricular rate ~108 bpm
  • Atrial rate ~214 bpm
Rhythm:
  • Regular
Axis:
  • LAD (-50 deg)
Intervals:
  • Apparent PR - Short / Normal (~120ms)
  • QRS - Prolonged (140ms)
  • QT - 440ms (QTc Bazette ~ 550 ms)
Additional:

  • P Waves superimposed on T waves best seen V1-2

Atrial activity with p waves superimposed in T wave
Click to enlarge
  • LBBB Morphology
    • Discordant ST Elevation V1-4
    • Discordant ST Depression V6
Interpretation:

  • Atrial Tachycardia 
    • 2:1 Conduction
  • LBBB
    • Old in this case


What happened?

The patient spontaneously cardioverted.
Prior echocardiography had shown marked left atrial dilation.
Further episode of atrial tachycardia requiring DC cardioversion.
Underwent left atrial mapping which showed atypical mitral isthmus flutter which was ablated.

References / Further Reading

Life in the Fast Lane
  • Atrial tachycardia here
Article - If you want to read a bit about EP studies and differing types of atrial tachycardia
  • Saoudi N, Cosio F, Waldo A, Chen SA, Iesaka Y, Lesh M, Saksena S, Salerno J, Schoels W. Classification of atrial flutter and regular atrial tachycardia according to electrophysiologic mechanism and anatomic bases: a statement from a joint expert group from the Working Group of Arrhythmias of the European Society of Cardiology and the North American Society of Pacing and Electrophysiology. J Cardiovasc Electrophysiol. 2001 Jul;12(7):852-66. Full text here

Textbook
  • Chan TC, Brady WJ, Harrigan RA, Ornato JP, Rosen P. ECG in Emergency Medicine and Acute Care. Elsevier Mosby 2005.
04.10.13
by

ECG of the Week – 8th April 2013 – Interpretation


This ECG is from a 52 year old male presenting with chest pain.




Click to enlarge


Rate:
  • ~108 bpm
Rhythm:
  • Irregularly irregular
  • Sinus rhythm
  • Frequent PVCs
    • Unifocal
    • Single & Couplets
    • Evidence of compensatory pauses
Axis:
  • Sinus Complexes - Normal (+70 deg)
  • PVC - LAD
Intervals:
  • PR - Normal (~180ms)
  • QRS - Sinus Complexes - Normal (100ms)
  • QRS - PVCs - Prolonged (120-140ms)
  • QT - 320ms (QTc Bazette ~ 420 ms)
Segments:

  • ST Elevation Leads
    • II (1mm),III (2mm), aVF (3mm)
    • ? V6 (0.5mm) - single complex with uneven baseline
  • ST Depression  Leads aVL, V1-3

Additional:

  • T wave inversion aVR, aVL, V1-3
  • P wave inversion Leads aVR, V1-2
  • R wave V1-3
  • PVCs - Discordant T wave & ST segment changes

Interpretation:

  • Acute STEMI
    • Inferior with ? postero-lateral involvement
This is an older case from my ECG collection but the clinicians looking after this patient were concerned about possible right ventricular involvement as an ECG with partial right precordial leads, V3-5R, was performed which is below:


Click to enlarge


There is no evidence for ST elevation in the right sided leads making RV involvement very unlikely. I don't know if posterior leads were performed, I don't have a posterior lead ECG from this case.

What happened ?

This is an older case from early 2012 but I managed to get some information on the ultimate outcome.

The ECG features were immediately recognized and STEMI protocol was activated.
The patient underwent an uneventful transfer for PCI which revealed a 100% occlusion of the proximal RCA which was stented.

The patient was commenced on aspirin, prasugrel, statin, ACE, and beta-blocker therapy. 
He was discharged after a 3 day in-patient stay.
References / Further Reading

Life in the Fast Lane
Textbook
  • Chan TC, Brady WJ, Harrigan RA, Ornato JP, Rosen P. ECG in Emergency Medicine and Acute Care. Elsevier Mosby 2005.
04.04.13
by

The Wenckebach Counter-Intuition

We are going to depart a little from our usual format today and address an ECG related question we asked yesterday.

This all stem's from this week's ECG which showed a Type I 2nd Degree AV block, a.k.a Wenckebach conduction. 



Features of Wenckebach

So we know the features of Wenckebach conduction, which are:

  • Progressive PR lengthening resulting in non-conducted P wave
  • Progressive R-R interval shortening
  • R-R interval length of dropped beat less than twice shortest R-R cycle
  • Grouped beating
But let's stop for a second, the PR gets longer whilst the R-R gets shorter, that doesn't seem to make sense. 

Why given the progressive PR prolongation do you get R-R interval shortening ?

Let's look at some of features of Wenckebach conduction again:
  • Progressive PR lengthening
    • BUT the magnitude of the lengthening progressively decreases
    • The greatest increase in PR is from the 1st to 2nd beat following a dropped complex
  • Regular P waves
    • P-P interval is relatively fixed
We'll that has certainly cleared everything up !

This is quite a migraine inducing concept to think through and it made more sense when I went through a Wenckebach example.


Wenckebach Example

So let's assume:
  • P wave occurs every second
    • We have regular P wave activity with a relatively fixed P-P interval
  • PR intervals increases by 0.1s then 0.08s then 0.06s
    • We have progressive lengthening but with a decreasing magnitude
  • Let's assume the first PR interval is 0.2s
  • So the PR intervals are 0.2s -> 0.3s -> 0.38s -> 0.44s
  • Now let's start our conduction at time 0 seconds


Time (s)      0         0.2         1        1.3         2         2.38        3       3.44        4

Event          P        QRS       P        QRS      P        QRS        P      QRS       P

  • This means the R-R intervals are 1.1s -> 1.08s -> 1.06s
    • Progressive shortening
  • This is also the reason why the largest R-R interval is less than twice the shortest R-R interval, I'll let you do the math's on this one.
I found drawing a 'ladder diagram' helped me organise my thoughts so I scanned my scribbling and stuck it here.


Click to enlarge
You can see how ladder diagrams can be used at Nelson's EKG site here.


Christopher's response to our Wenckebach question

Christopher , a fellow ECG enthusiast and regular contributor to the comments section, posted an excellent explanation for our PR/RR puzzler. His comments can be found on the blog here, and I've pasted them below.

The amount the PR interval prolongs becomes less with each beat, leading to the shortening R-R interval (presuming a fixed P-P).

I found it to be an abstract concept to wrap my head around at first!

If you think of the R-R in terms of the PRi, it is a bit easier. With a fixed PRi you have a fixed R-R (we'll assume a fixed P-P). If you simply have a longer PRi the R-R does not change, and the same goes for a shorter PRi.

The PRi dictates when the R's occur relative to the P's.

If you vary the PRi from beat-to-beat, then you'll change when the R's occur from beat-to-beat. If you change when the R's occur, you'll change the R-R.

Going back, constant PRi's do not affect the R-R. Thus the amount which varies from beat-to-beat is the change in the R-R.

In AV Wenckebach the amount of beat-to-beat prolongation which occurs lessens (or stays the same), with the largest delta-PRi occurring in the first beat (e.g. 200ms, 260ms, 290ms, 310ms, drop; deltas of 60, 30, and 20). So, if the amount we vary decreases with each beat, the R-R will decrease with each beat.

Put in math form, assuming k is our baseline PRi and we have a repeating series of PRi's:

PRi := { k, k60, k90, k110, k, k60, ... }

The n'th R-wave (we'll ignore drops, and P is the PP interval):
R_n := nP + PRi_n

With an R-R:

RR_n := R_n+1 - R_n

:= ((n+1)P + PRi_n+1) - (nP + PRi_n)

:= (n+1)P - nP + PRi_n+1 - PRi_n

:= P + (PRi_n+1 - PRi_n)

If you plug in the PRi's in order you'll find you get a decremental series:

RR := { P + 59k, P + 30k, P + 20k, ... }

I hope that helps others understand it, I had to draw it a lot when I first noticed the decreasing R-R's.
Christopher if I messed up your math's formatting with the copy / pasted let me know and I'll fix it, thanks John.

04.03.13
by

ECG of the Week – 1st April 2013 – Interpretation

We didn't have any clinical information on this week's ECG, but that shouldn't stop us being able to review the ECG.




 


Click to enlarge

Rate:
  • Ventricular rate 48 bpm
  • Atrial rate 66 bpm
Rhythm:
  • Sinus
  • Regular atrial activity
    • P-P interval relatively fixed
    • R-R interval progressively shortens
  • Progressive PR prolongation culminating in a non-conducted p wave
    • 4:3 & 3:2 relationship (atrial:ventricular activity)
Axis:
  • Normal (-50 deg)
Intervals:
  • PR - Progressive prolongation (~210 - 360 ms)
  • QRS - Normal (100ms)
  • QT - 480ms (QTc Bazette ~ 480 ms)
Segments:
  • Slight concave / flat ST elevation V2-4
  • No ST depression
Additional:
  • P Wave Inversion V1,V2, aVL
    • ? V2 inversion secondary to lead placement as other P wave morphology appears normal
Interpretation:

  • AV Block
    • 2nd Degree
    • Mobitz Type I
    • Wenckebach
Clinical Implication
  • I don't have any clinical information on this case, so I don't know the likely cause or outcome.
  • Type I second-degree AV block
    • Can occur during sleep in healthy people
    • It is NOT normal during waking hours
    • Can result in significant exercise limitation if occurs during waking hours
  • Symptomatic patient may require atropine +/- chemical +/- electrical pacing.
  • Cardiology referral should be made for patients found to have a Wenckebach conduction for specialist opinion on management, further investigation, and PPM consideration

Multiple causes, as Clare had pointed out in her comments, which include:
  • Ischaemia / Infarction
  • Drugs - anti-arrhythmic, lithium, alcohols
  • Inflammatory - myocarditis, endocarditis, Lyme's disease
  • Metabolic
  • Infiltrative diseases - amyloid, sarcoid
  • Obstructive Sleep Apnoea
  • Athletic Heart

Features of Wenckebach

Thanks to Jason for highlighting the cardinal features of Wenckebach which are:
  • Progressive PR lengthening resulting in non-conducted P wave
  • Progressive R-R interval shortening
  • R-R interval length of dropped beat less than twice shortest R-R cycle
  • Grouped beating
Something to think about ...
 
Why given the progressive PR prolongation do you get R-R interval shortening ?
References / Further Reading 

Life in the Fast Lane
  • Wenckebach Phenomenon here
  • Wenckebach Squared ECG Case here
eMedicine
  • Second-Degree Atrioventricular Block here
Textbook
  • Chan TC, Brady WJ, Harrigan RA, Ornato JP, Rosen P. ECG in Emergency Medicine and Acute Care. Elsevier Mosby 2005.
03.27.13
by

ECG of the Week – 25th March 2013 – Interpretation

This ECG is from a 40 yr old male who presented following a large overdose of an anti-spasmodic agent.







Click to enlarge
Rate:
  • 66
Rhythm:
  • Sinus Arrhythmia
Axis:
  • Inferior (+90 deg)
Intervals:
  • PR - Normal (~120ms)
  • QRS - Normal (~80ms)
  • QT - 560-600ms (QTc Bazette ~ 610-630 ms)
    • Note absolute QT interval greater than 1/2 of R-R interval
Segments:
  • Up-stroked ST segment I, V2-4
Additional:
  • T Wave Inversion aVL, aVR
Interpretation:
  • Marked QT Prolongation
    • Secondary to toxic ingestion
    • Using QT-RR Nomogram as described by Chan et al. this patient is 'at risk' of developing Torsades de Pointes
Check out the links below for more examples of toxicological QT prolongation from Life in the Fast Lane, and a link to the Chan et al. article describing a QT nomogram for TdP risk stratification in drug-induced QT prolongation.

References / Further Reading

Life in the Fast Lane Blog
  • The QT Interval here
  • Drugs Causing QT Prolongation here
  • Clinical cases of drug-induced QT prolongation
  • Polymorphic VT & TdP here
The Blunt Dissection Blog

  • ECG & Case of toxicological QT prolongation here

Article
  • Chan A, Isbister GK, Kirkpatrick CMJ, Duffu SB. Drug-induced QT prolongation and torsades de pointes: evaluation of a QT nomogram. QJM 2007 100(10):609-615 PMID: 17881416 Full text here
Textbook
  • Chan TC, Brady WJ, Harrigan RA, Ornato JP, Rosen P. ECG in Emergency Medicine and Acute Care. Elsevier Mosby 2005.
03.20.13
by

ECG of the Week – 18th March 2013 – Interpretation

For those of you at SMACC 2013 (Twitter #SMACC2013) this one will be familiar.
 
These ECGs are from a 58yr old male seen in a rural setting, approximately ~2500 km from the nearest tertiary centre.
 
He c/o intermittent atypical chest pain for several weeks without any cardiac risk factors.
At the clinic serial ECGs were performed and are below.
  • What do you think of the ECGs ?
  • What advice would you give assuming you were the clinician at the tertiary receiving hospital who was contacted regarding this case ?

 


 
First ECG
Click to enlarge

Second ECG
Click to enlarge
ECG 1
Rate:
  • 84
Rhythm:
  • Regular
  • Sinus Rhythm
Axis:
  • Normal (70 deg)
Intervals:
  • PR - Normal (~160-200ms)
  • QRS - Normal (80ms)
  • QT - 340ms (QTc Bazette ~ 390 ms)
Segments:
  • Slight Saddling ST segments leads II, III, aVF

ECG 2

Rate:
  • 66
Rhythm:
  • Regular
  • Sinus Rhythm
Axis:
  • Normal (-15 deg)
Intervals:
  • PR - Normal (~180 ms)
  • QRS - Normal (80ms)
  • QT - 360ms (QTc Bazette ~ 360 ms)
Segments:
  • Slight Saddling ST segments leads I, aVL
Additional:
  • T Wave Inversion Leads III, aVF
Interpretation:
  • This ECG was interpreted as having dynamic ST change ? ACS.
  • The patient was anti-coagulated and transferred by air, ~2500 km, to a tertiary centre for further Mx.
 But let's look again:

  • As those of you who have read the comments for this ECG will realise the answer is somewhat less pathological.
  • There is an axis change between the 2 ECGs which is a little odd
  • Look at the complexes in leads III and you can see not only has the T wave become inverted but so has the P wave and QRS complex
Click to enlarge

  • Compare leads aVL & aVF between the two ECGs and we can see these leads have been swapped
Click to enlarge

  • The ECG changes are due to a LA / LL lead reversal

  • As Christopher has pointed out this results in:
    • Leads aVL & aVF swap places
    • Leads I & II swap places
    • Lead III becomes completely inverted
    • Lead aVR remains unchanged
    • No change in the precordial leads

References / Further Reading
 
Life in the Fast Lane
  • Limb Lead Reversals here
Textbook
  • Chan TC, Brady WJ, Harrigan RA, Ornato JP, Rosen P. ECG in Emergency Medicine and Acute Care. Elsevier Mosby 2005.
03.15.13
by

ECG of the Week – 18th March 2013

For those of you at SMACC 2013 (Twitter #SMACC2013) this one will be familiar.

These ECGs are from a 58yr old male seen in a rural setting, approximately ~2500 km from the nearest tertiary centre.

He c/o intermittent atypical chest pain for several weeks without any cardiac risk factors.
At the clinic serial ECGs were performed and are below.
  • What do you think of the ECGs ?
  • What advice would you give assuming you were the clinician at the tertiary receiving hospital who was contacted regarding this case ?



First ECG
Click to enlarge
Second ECG
Click to enlarge

03.13.13
by

ECG of the Week – 11th March 2013 – Interpretation

This week's ECG is from a 57 year old female.
 
I don't have any presenting complaints for this case but it is likely she would complain of weakness.
 
 
Click to enlarge
Rate:
  • 60 bpm
Rhythm:
  • Sinus Arrhythmia
 
Axis:
  • Normal (50 deg)
Intervals:
  • PR - Prolonged (~220ms)
  • QRS - Normal (100ms in lead II, prolonged in lead V2)
  • Apparent QT - 680ms (QTc Bazette ~ 710 ms)
Segments:
  • ST Depression Leads I, II, V2-6
  • ST Elevation aVR
Additional:
  • Ventricular Ectopic
  • Prominent U waves
  • T-U Fusion
    • Best visualised in leads II, III, aVF, V2-6
    • Initial T wave is inverted and merges with large U wave
    • Results in apparent QT prolongation due to fusion
    • Best considered QU prolongation
Interpretation:
 
  • Multiple ECG features consistent with hypokalaemia +/- hypomagnesaemia
 
This patient had a K+ of 1.6 mmol/L confirmed by a VBG, result below.
 
 
 
References / Further Reading
 
Life in the Fast Lane
Textbook
  • Chan TC, Brady WJ, Harrigan RA, Ornato JP, Rosen P. ECG in Emergency Medicine and Acute Care. Elsevier Mosby 2005.
03.06.13
by

ECG of the Week – 4th March 2013 – Interpretation

Again no clinical information on this case.
 
 
 
 
 
Click to enlarge
Rate:
  • Ventricular ~ 85 bpm
  • Atrial ~ 250-300 bpm
Rhythm:
  • Regularly irregular
    • R-R Interval cycles from 520 ms and 960 ms
Axis:
  • Normal (60 deg)
Intervals:
  • PR - No p waves visible
  • QRS - Normal (80-100ms)
  • QT - 380ms (QTc Bazette variable due to RR irregularity)
Segments:
  • ST Elevation V3 1mm
    • Coincides with flutter wave superimposition
Additional:
  • Flutter waves best visualised in II, III, aVF, aVL
    • Positive V1
    • Typical anticlockwise
  • QRS alternans
    • Second complex in pair slight differing voltage
Interpretation:
  • Atrial flutter with variable block

References / Further Reading
 
Life in the Fast Lane
 
Textbook
  • Chan TC, Brady WJ, Harrigan RA, Ornato JP, Rosen P. ECG in Emergency Medicine and Acute Care. Elsevier Mosby 2005.
02.27.13
by

ECG of the Week – 25th February 2013 – Interpretation


No clinical information on this one.


 

 

 
Click to enlarge

Rate:
  • 42
Rhythm:
  • Regular ventricular complexes
  • Irregular atrial activity
  • Complexes 3 & 4 sinus
Axis:
  • LAD (-50 deg)
Intervals:
  • PR - Normal (~180-200ms) for 3rd & 4th Complexes only
  • QRS - Prolonged (~120ms)
  • QT - 720ms (QTc Bazette ~ 600 ms)
Segments:
  • Slight down sloping ST Depression V5-6
Additional:
  • T wave inversion I, aVL, V1, V3-6
  • QRS Morphology RBBB Pattern
  • Differing QRS Morphology between complexes 1-2,5-7 and complexes 3-4
  • Difficult to map atrial activity given relative low voltage p wave
  • R wave progression abnormal across precordial leads
    • ? V2 misplacement - terminal deflection QRS >> than V1&2 with positive T wave
Interpretation:
  • Intermittent trifasicular block likely complete
    • Bifasicular block with variable sinus capture & high grade AV block

References / Further Reading

 
Life in the Fast Lane

 
  • Trifasicular Block here
Textbook
  • Chan TC, Brady WJ, Harrigan RA, Ornato JP, Rosen P. ECG in Emergency Medicine and Acute Care. Elsevier Mosby 2005.
02.20.13
by

ECG of the Week – 18th February 2013 – Interpretation


Final part of the ECG trilogy.


 

The nursing staff come and get you to say the patients rhythm has changed on the monitor and they've ran off a new ECG.


 

 


 

 
Click to enlarge


Rate:
  • Ventricular 90 - 100 bpm
Rhythm:
  • Ventricular paced
  • Subtle irregularity
Axis:
  • LAD (-70 deg)
Intervals:
  • QRS - Prolonged (160-180 ms)
  • QT - 480ms (QTc Bazette ~ 580 ms)
Segments:
  • ST Elevation II, III, aVF, V4
  • ST Depression I, aVL
  • All ST changes discordant to QRS
Additional:

  • T wave Inversion I, aVL, aVR, V1-2
  • Notching in leads V1-3
    • ? Atrial activity rate ~150 bpm although appears somewhat irregular
    • Would a Lewis lead configuration have helped ? Read more about the Lewis lead on one of our earlier ECGs here.
  • RBBB morphology  – different again from QRS morphology on ECGs 1 & 2
  • Subtle QRS alternans – Thanks to Christopher and Vince for spotting this one
  • Final complex is only partially included but morphology appears different with ? p wave post pacing spike with fusion morphology - Thanks to Vince for pointing this out

I would encourage all our readers to take a look at the comments from both Christopher & Vince on this one.

Vince raises an interesting point regarding the QRS alternans being a potential marker for ischaemia in the setting of a paced rhythm although I don't know much about this phenomenon and will try to source some literature evidence (Vince - any pointers ?)

Christopher correctly points out that RBBB morphology in a presumed RV paced rhythm is unusual, a quick literature search reveals a number of case reports on this topic. I've linked to one freely available paper in the reference section that gives a nice brief overview of RBBB morphology and RV pacing.

I, like Christopher, am no pacemaker ninja. I will update this post once I hear from our cardiology / emergency physician co-authors on this one.  I agree with both Christopher and Vince that it is the most interesting ECG of this trilogy and highlights again the need for a thorough and systematic interpretation of an ECG, as at first glance this appears to be 'just' a paced rhythm.

References / Further Reading
 
 
Papers
  • Erdogan O, Aksu F. Right bundle branch block pattern during right ventricular permanent pacing: Is it safe or not? Indian Pacing Electrophysiol J. 2007 Jul-Sep; 7(3): 187–191. Full text here