Initial experience of a new thin unipolar pacing lead

This multicenter clinical study was carried out to investigate the electric al properties of a new thin (4.5F) unipolar pacing lead with a 2.3 mm2 tip surface area. The lead tip is made of titanium and a titanium nitride micro structure covered with a thin membrane containing less than 30 ug of the st eroid dexamethasone. The lead, Model 1470K (St Jude Medical - Pacesetter), was implanted in 30 patients with a mean age of 70 years. The pacing parame ters were tested using pacemaker telemetry before discharge and 2 weeks, 1 month, 3 and 6 months after implant, respectively. In all patients Trilogy pacemakers (St Jude Medical - Pacesetter) were used, in 27 patients the DR, in 2 patients the DC+ and in I patient the SR+ model. Lead impedance was determined using the measured data display. Sensing and pacing thresholds w ere measured by semiautomatic tests. Handling characteristics were evaluate d. Over the 6 months of follow-up the pacing thresholds and sensing characteri stics were stable at satisfactory levels while the impedance values increas ed continuously to a moderately high level. Handling of the lead during imp lantation was generally rated as very good or good. In conclusion, the new thin lead has satisfactory electrical properties and offers a good compromise between high impedance and low polarization.