Long-term superiority of steroid elution in atrial active fixation platinum leads

Steroid elution reduces the acute increase in stimulation threshold particu larly in active fixation leads. The aim of this study was to investigate th e long-term efficacy of steroid elution in atrial screw-in leads compared t o conventional lead design. Two different bipolar active fixation platinum lead designs were implanted. Leads were similar except for the presence (gr oup S, n = 66) or absence (group N, n = 68) of steroid elution. Patients re ceived dual chamber pacemakers with the following atrial leads in consecuti ve order: Medtronic 4058 M (group N, n = 30), Medtronic 4068 (group S, n = 40), Vitatron IMS 13 (identical to 4058 M, group N, n = 38), and Vitatron I MX 13 (identical to 4068, group S, n = 26). The mean follow-up period was 4 0.7 +/- 16.1 months (range 10 to 84 months). Stimulation thresholds, pacing impedances, P wave potentials, and sensing threshold M ere assessed for bo th groups immediately, 10 days, 6 weeks, and 3 months after implantation fo llowed by 6-months intervals. Energy thresholds, chronaxie-rheobase product s, and energy consumption of atrial pacing were calculated. Chronic values were deduced from the most recent measurement performed in an individual pa tient. Within the first 10 days after implantation, atrial voltage threshol d at pulse duration of 0.4 ms increased from 0.91 +/- 0.42 to 2.06 +/- 0.45 V in group N (P < 0.001). Less increase was observed in group S (0.83 +/- 0.39 to 1.08 +/- 0.53 V, P = 0.003). A trial voltage thresholds remained ma rkedly lower in steroid-eluting leads during whole follow-up (1.12 +/- 0.49 V in group S vs 1.58 +/- 0.71 V in group N, P < 0.01). Chronic energy cons umption was markedly reduced in group S (4.0 +/- 2.7 mu J) compared to grou p N (9.8 +/- 7.5 mu J, P < 0.001). An atrial voltage threshold below 1.25 V at 0.4 ms was achieved in 92.3% of patients of group S allowing programmin g of an output of 2.5 V. Such low outputs were feasible in only 49.3% of pa tients in group N (P < 0.001). Chronic P wave amplitudes did not differ sig nificantly between groups (3.27 +/- 1.81 mV in group N vs 3.24 +/- 1.18 m V in group S, P = 0.91). Steroid elution diminishes the increase of stimulat ion thresholds of nonsteroid atrial active fixation platinum leads resultin g in a long-term reduction of energy consumption. Thus, use of steroids can be recommended for general use in atrial active fixation lead designs.