Reversal of arm leads is the commonest error when recording an ecg/ekg.
Negative P in lead 1 is an useful diagnostic clue.
Chest leads show normal transition with tall R in lead reversal , whereas in true mirror-image dextrocardia the QRS complex becomes smaller and displays mostly QS or rS in v4-v6.
Also as we know lead 1 v5 v6 show same polarity a they are all lateral leads.If lead 1 qrs predominantly negative while v5,6 is positive, suspect reversal.
