ECG of the Week: ECG of the Week - 30th September 2013

This ECG is from a 88 year old male who presents following multiple episodes of pre-syncope during the day. Past history of hyperlipidaemia, hypertension, atrial fibrillation, and CVA.

Medications include warfarin, metoprolol, and a diuretic. He is not taking digoxin or other antiarrhythmics.
Check out the extensive and excellent comments on these ECG's from our original case post here.

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ECG 1 - on presentation
Click to enlarge

ECG 1

Rate:

126 bpm

Rhythm:

Regular
P waves

Negative leads I, aVL
Isoelectric lead II
Positive lead III

Axis:

Right axis deviation (+95 deg)

Intervals:

QRS - Prolonged (110ms)
QT - 280ms (QTc Bazette ~ 405 ms)

Segments:

ST Elevation leads aVR & V1 (0.5mm)
ST Depression leads II, III, aVF, V2-6

Additional:

rSR' Pattern V1

Interpretation:

AVRT (likely rhythm)

P wave morphology consistent with concealed left lateral accessory pathway
Other DDx Atrial tachycardia (less likely rhythm)

This is not AVNRT or Junctional Tachycardia

The p wave morphology is not consistent with these rhythms
For AVNRT & Junctional Tachy we should see negative P waves in leads II, III, aVF and positive P waves in aVL & usually lead I.

Differential diagnosis

Broad range of differentials for this ECG including:

Ischaemia
Electrolyte abnormality
Drug toxicity
Myocarditis
Pulmonary hypertension
ASD

Shortly after the ECG above patient had a brief period of asystole and the ECG following this episode is below.

ECG 2 - following asystole
Click to enlarge

ECG 2

Rate:

Rhythm:

Regular
Sinus rhythm

Axis:

Right axis deviation (+95 deg)

Intervals:

PR - Prolonged (240ms)
QRS - Normal (100ms)
QT - 440ms (QTc Bazette 365 ms)

Segments:

ST Elevation aVR (0.5mm)
ST Depression leads II, III, aVF, V2-6

Additional:

Biphasic P wave V1
rSR' pattern V1

So what happened ?

We have an elderly with a history of atrial fibrillation presenting with a tachyarrhythmia followed by an asystolic event and subsequent bradyarrhythmia.
My initial thoughts for this case was one of sinus node dysfunction (tachy/brady syndrome).
The patient had a potasssium of 6.0 mmol/L and an initial troponin of 0.06 mcg/L [normal <0.05 mcg/L] which increased to 0.41 on serial testing, so a likely ischaemic precipitant for this event.
Whilst in the Emergency Department the patient had a second asystolic event which responded to atropine and precordial thump. Following pacing was performed and PPM insertion was planned. Unfortunately the patient's condition rapidly deteriorated with multi-organ failure, active treatment was ceased and palliative care measures instituted .

A number of comments suggested a possible PE in this case, however the patient is elderly and on warfarin which makes PE unlikely and the multiple syncopal episodes also don't favour PE given the absence of haemodynamic collapse. Given the subsequent arrest, if caused by PE, I would not expect to get ROSC without very aggressive therapy +/- lysis, whereas in this case the patient recieved a precordial thump with resultant rhythm above (ECG 2). The post ROSC ECG also shows a bradycardia, in the setting of PE we would expect to see a persistant tachycardia.

References / Further Reading

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