Sometimes an ECG is not made properly. Mistakes do happen and<unk> s can be switched. Always remain careful to check this or you might come to the wrong conclusions. One of the most common mistakes is to switch the right and left arm. This will result in negative complexes in I, indicating a right axis deviation!
Common mistakes are reversal of:
Right leg and right arm:
Hardly seen any signal in<unk>  II.
Right and left arm electrodes;
Reversal of<unk> s II and III
Reversal of<unk> s aVR and aVL
Left arm and left leg:
Reversal of<unk> s I and II
Reversal of<unk> s aVR and aVF
Inversion of<unk>  III
Right arm and left leg:
Inversion of<unk> s I, II and III
Reversal of<unk> s aVR and aVF
Hardly seen any signal in<unk>  II.
Reversal of<unk> s II and III
Reversal of<unk> s aVR and aVL
Reversal of<unk> s I and II
Reversal of<unk> s aVR and aVF
Inversion of<unk>  III
Inversion of<unk> s I, II and III
Reversal of<unk> s aVR and aVF
It is possible to distinguish<unk>  reversal and dextrocardia by watching the precordial<unk> s. Dextrocardia will show an R wave inversion, whereas<unk>  reversal will not.
EKG lead placement errors
EKG artifacts
Runaway pacemaker syndrome
Noncompaction cardiomyopathy arrhythmias
Abrupt closure during coronary intervention
ST elevation myocardial infarction complications
Patent foramen ovale post-surgical complications
Acute coronary syndromes