ECG of the Week - 22nd May 2017 - Interpretation

The following ECG is from a 67yr old male who presented with a 36 hour history of central chest pain and diaphoresis. He has a history of CABG. 

Click to enlarge

Rate:

• Ventricular rate 36 bpm
• Atrial rate ~ 60 bpm

Rhythm:

• Regular ventricular and atrial rhythms
• Complete heart block

Axis:

• Normal

Intervals:

• PR - AV dissociation with no relation between P and QRS
• QRS - Normal

Segments:

• ST Elevation leads II (1mm), III and aVF (3mm) V5-6 (1mm)<1mm avf="" font="" iii="" mm="" v5-6="">
• ST Depression leads V2 - flat morphology
• ST Depression leads I, aVF

Interpretation:

• Infero-lateral STEMI
• Likely posterior extension
• Complete heart block
• Ventricular bradycardia with narrow complex escape rhythm

What happened ?

The patient was taken for urgent angiography which showed:

• LMCA: 80% Stenosis
• LAD: Patent LIMA (left internal mammary artery) and SVG (saphenous vein graft)
• Cx: Patent SVG
• RCA: Subacute thrombotic occlusion with severe ostial and proximal vessel stenosis.

The RCA lesion was stented but the patient's recovery was complicated by repeated PEA, VT and VF cardiac arrests necessitating placement of an Intra-Aortic Balloon Pump (IABP).

A bit on IABPs

Check out the following LitFL pages for a nice overview of IABPs:

• IABP - Case & Questions
• IABP - Critical Care Compendium Overview

A bit on CABG anatomy and techniques

This is outside of the scope of this blog but I found the following links useful refreshers on CABG techniques and post CABG angiography / intervention:

• LitFL - CABG Overview
• CTSNet - Post CABG Angiography and Interventions
• Dr Venkatesan Blog - Why is LIMA graft superior to saphenous venous graft in CABG ? - Nice Pictures

References / Further Reading

Life in the Fast Lane

• Inferior STEMI
• Complete heart block 

Textbook

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