Normally functioning inhibited pacemaker concomitant with vertebral nerve stimulator.

Electromagnetic inference is a recognized difficulty in concomitant cardiac pacing and nerve stimulation. A case is reported in which a vertebral nerve stimulator was implanted, with a transmitter antenna distal to the right nipple. Six months later, intermittent S-A block with Adams-Stokes attacks urgently necessitated cardiac pacing. The ECG lead II showed nerve stimulator potentials of 0.75 mV. Intracardiac electrogram with unipolar electrode registered potential of 0.25 mV, but with a bipolar system no such potentials were observed. A bipolar pacing electrode was therefore implanted, with an interference from the nerve stiumluator. Various aspects of interference are discussed.