ECG Case 008

Main Abnormalities

• Widespread ST depression affecting multiple precordial (V2-6) and limb leads (esp. I, II, avF).
• To some extent this is masked by an indistinct J point, upsloping (rather than horizontal) ST depression, and some baseline wander of the ECG
• There is marked ST elevation in aVR, measuring ~3mm

• ST depression in aVF relative to the T-P baseline.
• The blue arrow denotes the approximate position of the J point.
  

• ST elevation in aVR
  

Diagnosis

In the context of ischaemic chest pain and cardiogenic shock, the combination of…

• Widespread ST depression
• Marked ST elevation in aVR > 1 mm
• ST elevation in aVR > V1

… is extremely concerning for left main coronary artery (LMCA) occlusion.

However, this pattern is not entirely specific for LMCA occlusion. It may be seen whenever there is severe diffuse subendocardial ischaemia, as a result of oxygen supply-demand mismatch:

• Severe triple vessel disease
• Severe anaemia or hypoxaemia
• Following resuscitation from cardiac arrest

This patient developed progressive cardiogenic shock complicated by runs of ventricular tachycardia. He was taken for immediate angiography where he was found to have a complete ostial occlusion of his left main coronary artery. 

A similar ECG pattern of diffuse ST depression with ST elevation in aVR may also be seen with supraventricular tachycardias (AVNRT / atrial flutter).

This rate-related change is usually benign and resolves with resolution of the SVT.

• Rate-related change due to SVT