Abstract
In a 14 year old girl a cardiac pacemaker with a pair of myocardial electrode has been implanted since 8 years old. As the first pair of the electrode fractured near its tip, the second pair was added. Thus, the patient had two pairs of myocardial electrodes with one demand pacemaker implanted. When she was readmitted to hospital because of light-headedness, ECG monitor revealed the frequent suppression of pacemaker emission consequent on transcutaneous waving of pacemaker unit. Application of the magnet over the generator resulted in no inhibition even on moving the unit. The pacemaker pocket was reopened. Waving of the active myocardial electrode or pacemaker unit did not inhibit the demand pacemaker, but manipulation of the inactive lead induced the suppression of pacemaker emission. Such manipulation produced interference waves of about 10mV in amplitude, which were caused probably by the motion of the cut end of the inactive leads in the patient's abdominal muscle. The exchange of the demand pulse generator to a fixed mode was followed by complete disappearance of light-headedness in this case.
