Safety of nerve conduction studies in patients with implantable cardioverter–defibrillators

Abstract Objective A patient with an implantable cardioverter–defibrillator (ICD) may suffer from neuromuscular disorders and may need to undergo a nerve conduction study (NCS). However, a NCS may be a source of electromagnetic interference (EMI). The aim of the present study was to investigate whether the interference from NCS used in a standardised test protocol affects ICD function. Methods Twenty patients (19 males; mean age of 59.8±9.9years) with implantable ICDs (eight with integrated and 12 with true bipolar leads), treated with amiodarone and with symptoms suggesting neuropathy were included. NCS were conducted using repetitive stimulation with frequency of 2Hz and single, rectangular pulses of intensity up to 100mA. Stimulation was performed in standard sites including proximal sites in the arm. Results The impulses generated NCS were not detected by the ICD, irrespective of the site, rate or stimulus intensity. Conclusions Standardised test protocol for an NCS is safe in patients with an ICD regardless of the leads type. Significance Current guidelines which limitate the NCS in patients with ICD may be the subject of revision.