70-year old patient presenting with severe chest pain, diaphoresis and syncope. BP 65/40.


Describe and interpret this ECG


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
  • 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 in LMCA occlusion
  • ST elevation in aVR


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 severe left main coronary artery (LMCA) insufficiency.

However, this pattern is not entirely specific for LMCA insufficiency. 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 99% stenosis 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.

ECG SVT-ST-depression 2
  • Rate-related change due to SVT

TOP 100 ECG Series

Emergency Physician in Prehospital and Retrieval Medicine in Sydney, Australia. He has a passion for ECG interpretation and medical education | ECG Library |

MBBS (UWA) CCPU (RCE, Biliary, DVT, E-FAST, AAA) Adult/Paediatric Emergency Medicine Advanced Trainee in Melbourne, Australia. Special interests in diagnostic and procedural ultrasound, medical education, and ECG interpretation. Editor-in-chief of the LITFL ECG Library. Twitter: @rob_buttner


  1. Is there any significance to the axis deviation (QRS is positive in avR, biphasic in lead I and negative lead II)?
    Also, the wide complex QRS especially in V2-V4?
    And the irregularly irregular rhythm (AF)?

  2. Agree – In addition to the global STD and STE in aVR I read this as sinus tach. and frequent PAC with marked LAD, PRP and late transition associated with a left anterior hemi block – added observations which probably don’t carry extra clinical significance in the context of LMCA OMI.

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