#ECGclass - Spring4-iv - When ECGs go bad!

Welcome to another weekly case on ECGclass. :)
If you are new to either @ECGclass, #ECGclass, or this blog - please click  here to find out what it's all about! 

ECG class is delighted to welcome our second guest speaker of the term!

A big welcome to Simon Ross Deveau.

Simon can be found on Twitter @sydeveau or via his ECG blog:  Bits and Pieces from an ED Nurse
As an ED nurse, Simon has come across a variety of ECG problems in the ED.
Problems range from ED staff doing them wrong, ambulance crews querying ischaemia/ST deviation, and people being referred in with abnormal ECGs, who go on to have normal ECGs when electrodes and leads are positioned correctly. 

So this weeks ECG class looks at a case of mistaken identity.

What happens when ECGs are done wrong?

Thank you Simon! :)
Here goes, and have fun…..…

#ECGclass Spring4

Q1 What is the correct electrode position of the precordial leads?

Correct precordial lead positioning:

V1    L sternal border, 4th intercostal space. 
V2    R sternal border, 4th intercostal space 
V4    Midclavicular line, 5th intercostal space. 
V5    Anterioraxillary line
V6    Midaxillary line
V3    Midway between V2 & 4.

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Q2: What technical error does the ECG below show?

The ECG above shows leads RA & LA to be reversed. 

Lead I is –ve and aVR is +ve = general R direction of cardiac impulse. 
The differential diagnosis here would be right sided heart (dextrocardia/dextroposition).

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Q3 - How about this one?

This ECG shows reversal of V1-V6. 

Note the RS progression in reverse.

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Q4: Are we worried about this ECG?