Morphology of current of injury does not predict long term active fixation ICD lead performance.

Background: Currents of injury (COI) have been associated with improved lead performance during perioperative measurements in pacemaker and ICD implants. Their relevance on long term lead stability remains unclear.

Methods: Unipolar signals were recorded immediately after active fixation ICD lead positioning, blinded to the implanting surgeon. Signals were assigned to prespecified COI types by two independent investigators. Sensing, pacing as well as changes requiring surgical intervention were prospectively investigated for 3 months.

Results: 105 consecutive ICD lead implants were studied. All could be assigned to a particular COI with 48 type 1, 43 type 2 and 14 type 3 signals. Pacing impedance at implant was 703.8+/-151.6 Ohm with a significant COI independent drop within the first week. Sensing was 10.6mV+/- 3.7mV and pacing threshold at implant was 0.8+/-0.3mV at 0.5ms at implant. There was no significant difference between COI groups at implant and during a 3 months follow up regarding sensing, pacing nor surgical revisions.

Conclusions: Three distinct patterns of unipolar endocardial potentials were observed in active fixation ICD lead implant, but COI morphology did not predict lead performance after 3 months.