Short- and long-term results with an active-fixation, bipolar, polyurethane-insulated atrial pacing lead.

Since 1989, 136 Medtronic 4058 and 4058M bipolar atrial screw-in leads have been implanted at the Mayo Clinic. Early lead related complications included dislodgment in 4 (2.9%). Over a median follow-up time of 14.4 months (1 day to 3.3 years), there were 11 lead related complications (undersensing, failure to capture, diaphragmatic pacing, and gross lead dislodgment). Chronic complications resulted in reoperations in four patients (2.9%). Of 77 patients in whom pacing thresholds were measured between 2 and 4 months after implantation, 9 (11.7%) and 2 (2.6%) had high pacing thresholds and very high thresholds, respectively. The Kaplan-Meier estimate of the probability of 1-year complication-free lead survival was 93.5%. There were no lead material failures. We conclude that the 4058/4058M lead implanted in the atrial position has favorable acute and chronic performance data, with a tendency toward high pacing thresholds at 3 months. The cause of this phenomenon and its course over time should be further evaluated.