Commentary
We observed that mechanical contact between the old pacemaker and the new integrated bipolar defibrillator lead caused oversensing (“lead chattering”) resulting in inhibition of ventricular stimulation.
At this point, three possible solutions were at hand:
  1. Implantation of an additional septal pace/sense lead in appropriate distance to the integrated bipolar lead.
  2. Explantation of the new integrated bipolar defibrillator lead and exchange against a true bipolar ICD lead.
  3. Extraction of the 21 year old ventricular pacemaker lead.
Since we had utilized a DF-1 system, we decided to add a pace/sense lead and use the single-coil DF-1 part of the defibrillator lead which was placed in a good right ventricular apical position. [Fig 3.]
With the latest DF-4 standard, this would not have been possible. A new true bipolar defibrillator lead would have had to be positioned in the right ventricular outflow tract.