What are the contraindications for electromyography (EMG) and nerve conduction studies?

Updated: Aug 20, 2018
  • Author: Stephen Kishner, MD, MHA; Chief Editor: Jonathan P Miller, MD  more...
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Electrodiagnostic (EDX) studies should never be performed on patients with external wires like external pacing wires, guidewires, and so on. Central lines are not a contraindication, but the contralateral limb should be used. Patients with implanted cardiac pacemakers and cardioverter-defibrillators are not a contraindication to nerve conduction studies (NCS). Several studies have shown no pacemaker inhibition during NCS, but there has been one reported case of pacemaker failure due to peripheral nerve stimulation. There are no reported cases of implantable automatic cardioverter-defibrillators (IACDs) being triggered by NCS. For patients with IACDs, stimulation should not be performed near the implanted device and the contralateral extremity should be used when possible. Stimulation intensities should be kept under 1 Hz and pulse width under 0.2 ms duration because, theoretically, it could be confused by the device as a QRS complex/cardiac rhythm. Repetitive stimulation should also be avoided. 

Patients with bleeding disorders or who are anticoagulated are not a contraindication to EMG. However, extra care should be taken during the needle exam. There is a lack of official guidelines, but there are some general recommendations: the smallest gauge needle available should be used, study should be limited to superficial muscles, avoid deep muscles that could compress neurologic structures, and avoid muscles with large vasculature nearby. [11]

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