A new efficient NanoTip lead.

The ideal lead has low, stable acute and chronic thresholds, high pacing impedance, and good sensing. Leads with low, stable thresholds have been developed, but pacing impedance has been in the 600 omega region. One way to increase pacing impedance is to decrease the electrode's surface area. The threshold performance and sensing ability of less than 5 mm2 electrodes have been considered questionable, up to now. We have developed a 1.5 mm2 porous, platinized, steroid-eluting electrode and have demonstrated in canine studies that it has excellent performance. Chronic thresholds are low at about 0.65 +/- 0.28 V (ventricular) and 0.42 +/- 0.12 V (atrial) at 0.5 msec. Chronic pacing impedance is in the 1200-1300 omega region, but mean chronic R and P wave source impedance is less than or equal to 1500 omega. Sensing is excellent, with almost double the P wave amplitudes usually measured in the canine.