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Technical Problems

4 bytes removed, 06:26, 17 January 2010
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==Lead reversals==
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 this lead 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 reversalreversals''' lead to inappropiate inappropriate R wave progression (increase - decrease - increase) and are often easily recognized.
Therefore '''any right axis or small signal in an extremity lead''' should be reason enough to check lead positioning. A previous ECG can be very helpful.
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More specific patterns with every lead reversal:
*right leg and right arm:
**Hardly any diminished signal in lead II.*right and left arm electrodes; :
**reversal of leads II and III
**reversal of leads aVR and aVL
<gallery perRow="4">
Image:Noise_move.png|Movement artifacts
Image:ECG_Parkinson.png|Increasing movement artifacts in a Parkinson 's patient. The patient was in sinus rhythm! (which doesn't show on this short recording)!
Image:BaselineDrift.png|Baseline drift. The amplifier in the ECG machine has to re-find the 'mean'. This often occurs right after lead connection and after electric cardioversion.
Image:cardioversion_from_afib.jpg|Cardioversion from atrial fibrillation to sinus rhythm, with clear baseline drift.
Image:electric_noise_ecg.png|Electrical interference from a nearby electrical appliance. A typical example is a 100 Hz background distortion from fluorescent lights. Not to be confused with [[Atrial_Fibrillation|atrial fibrillation]].
Image:electric_noise_ecg2.jpg|Another example of an artefact artifact caused by an electrical appliance. The patients rhythm is regular. This strip shows 10 QRS complexes.
File:DVA2162.jpg|An artifact that was originally diagnosed as a VT
</gallery>
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