Technical Problems: Difference between revisions

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 ==Lead reversals==
-Sometimes an ECG is not made properly. Mistakes do happen and leads 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!
+Lead switches are a common mistake when ECGs are made and can lead to wrong diagnoses. Common mistakes are:
+* left - right arm reversals. This leads to a negative complex in lead I with also a negative P wave in lead I. It is one of the most common causes of right axis deviation on the ECG!
+* Arm - foot switches lead to a very small or 'far field' signal in leads II or III.
+* Chest lead reversal lead to inappropiate R wave progression (increase - decrease - increase) and are often easily recognized.
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-Common mistakes are reversal of:
+More specific patterns with every lead reversal:
 *right leg and right arm:
 **Hardly any signal in lead II.
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 **inversion of leads I, II and III
 **reversal of leads aVR and aVF
 It is possible to distinguish lead reversal and [[w:Dextrocardia|dextrocardia]] by watching the precordial leads. Dextrocardia will not show any R wave progression in leads V1-V6, whereas lead reversal will.