Clinical surveillance of a thin bipolar pacing lead

A total number of 415 co-radial, bipolar pacing leads (189 atrial leads; 22 6 ventricular leads) were implanted in 228 patients between November 1994 a nd July 1999. Mean pacing thresholds at the implantation were normal at 0.6 V in the atrium and at 0.4 V in the ventricle with a pulse duration of 0.4 -0.5 ms. Lead impedance was relatively low (337-447 ohms for atrial leads; 369-459 ohms for ventricular leads) at the implantation and during the foll owup periods. No definite failure in lead materials was observed in either atrial or ventricular leads (mean follow-up of 19.7 and 19.2 months, respec tively: up to 52.9 months for both leads). Predicted clinical surveillance up to 10 years calculated statistically showed that the upper 95% confidenc e limit was a constant of 100%. The lower 95% confidence limits at 5, 7, an d 10 years were estimated to be 98.0%, 97.2%, and 96.0%, respectively. From the present study, the ThinLine(TM) lead is reliable for both sensing and pacing thresholds, and has excellent predicted lead longevity. Nevertheless , further observation is required regarding cost performance, such as early replacement of the pacemaker generator, because of the lower pacing lead i mpedance.