ECG of the Week: ECG of the Week - 16th March 2015

This ECG series is from a 45 yr old male who was undergoing an out-patient exercise stress test (EST) for investigation of chest pain.
The first ECG is pre-EST. The second ECG was performed when the patient became pre-syncopal during EST. The third ECG was taken 2 minutes after the second ECG and the fourth ECG was performed a further 2 minutes later. The patient was immediately transported to the Emergency Department were he was pain free and ECG was comparable with his pre-EST ECG.
Check out the comments on our original post here.

ECG 1 - Pre-EST
Click to enlarge

ECG 1 - Pre-EST

Rate:

72 bpm

Rhythm:

Regular
Sinus Rhythm

Axis:

Normal

Intervals:

PR - Normal (160ms)
QRS - Normal (80ms)
QT - 340ms (QTc Bazette ~375 ms)

Additional:

Flat T wave aVL

Interpretation:

Normal ECG
Note the normal QTc in light of what happened next

ECG 2 - During EST patient complained of pre-syncope
Click to enlarge

ECG 2 - During EST patient complained of pre-syncope

Interpretation:

Polymorphic Ventricular Tachycardia (PMVT)
Alternating voltage direction and amplitude
Given the absence of preceeding QTc prolongation this is not Torsades de Pointes (TdP)
Remember the commonest cause of PMVT is myocardial ischemia
TdP is a specific form of PMVT seen in the setting of QT prolongation, acquired or congenital.

ECG 3 - 2 Minutes after ECG above. Nil ALS intervention required.
Click to enlarge

ECG 3 - 2 mins after ECG 2

Rate:

96 bpm

Rhythm:

Regular
Sinus Rhythm

Axis:

Normal

Intervals:

PR - Normal (140ms)
QRS - Normal (100ms)
QT - 300ms (QTc Bazette 380 ms)

Segments:

ST Elevation leads I(2mm), aVL(3mm), V1(<1mm), V2(3mm), V3(4mm),V4(5mm), V6(<1mm)
ST Depression leads II, III, aVF, aVR

Additional:

Abnormal R wave progression across leads V4 to V6 - Likely V5 position is incorrect

Interpretation:

Anterolateral STEMI

ECG 4 - 2 minutes after ECG 3. Patient pain free.
Click to enlarge

ECG 4 - 2 mins after ECG 3

Rate:

84 bpm

Rhythm:

Regular
Sinus rhythm

Axis:

Normal

Intervals:

PR - Normal (~180ms)
QRS - Normal (100ms)
QT - 320ms (QTc Bazette 380 ms)

Segments:

ST Elevation leads I (<1mm), aVL(1mm), V2(<1mm)

Significantly reduced compared with ECG 3

ST Depression leads II, III, aVF, aVR

Significantly reduced compared with ECG 3

Additional:

Hyperacute T waves in leads V2-4
Abnormal R wave progression across leads V4 to V6 - Likely V5 position is incorrect

Interpretation:

Dynamic resolution of ST segment changes ? unstable plaque vs vasospasm
Given prior ECGs impending anterolateral STEMI with high risk of arrhythmogenic death

What happened ?

Immediate liaison with interventional cardiology commenced ticagrelor / aspirin / heparin loading and patient was taken for urgent angio which showed: