Transient early T wave sensing by implanted programmable demand pulse generator

A seven-year-old girl with a permanent epicardial programmable pulse generator developed inappropriate slowing of the pacing rate due to oversensing a combination of T wave and afterpotential voltage. This phenomenon occurred only in the first three days after implantation and was demonstrable only at long programmed pulse widths. Our observations suggest that the current of injury in the early post-operative period may generate a relatively high T wave voltage capable of combining with a large afterpotential to produce a signal exceeding the sensitivity of a demand pulse generator.