Influence of pacing parameters on pacemaker longevity

 This study retrospectively assessed the parameters that affect pulse generator longevity in 78 patients implanted with dual-chamber pacemakers. Longevity was studied in 52 generators: 14 Cosmos II, 17 Relay, 11 Ellite II, and 10 Thera DR. The lifetimes of Cosmos II and Ellite II were significantly prolonged compared to those of Relay and Thera DR. The comparative study was conducted to evaluate the effect of low-impedance leads (ThinLine I, n = 10) on generator longevity compared with a standard lead (Irox, n = 16). No significant variation in pacing threshold was found between the groups. However, the low-impedance group provided significantly lower cell voltage and higher cell impedance during all follow-up periods compared with the standard lead impedance group. The internal current of the pacemaker with rate response and sophisticated diagnostic memory function (Relay, n = 5, and Marathon DR, n = 5) increased significantly compared with the conventional pacemaker (Cosmos II, n = 5). In conclusion, the selection of unnecessary pacing parameters and the selection of low-impedance leads should be avoided in order to extend generator longevity. Received: November 5, 2001 / Accepted: May 30, 2002 Correspondence to:N. Mizutani