VDD pacemaker replacement is safe and reliable independently of the previously implanted lead: a prospective and controlled study.

Unlabelled: Theoretically, replacement of a VDD device requires using a similar pacemaker to provide the best match between the filtering characteristics of the pacemaker and the atrial dipole of the lead. This study evaluated the performance of newly implanted Vitatron VDD pacemakers connected to dedicated leads and compared the results with those of the same Vitatron pacemakers used as replacement but connected to a variety of nondedicated leads.

Methods: 23 consecutive patients (15 M, 8 F, 78 +/- 6 years) in Group 1 underwent pacemaker replacement with a VDD(R) Saphir 3 (Vitatron BV, Arnhem, The Netherlands) device designed for an 8.6 mm atrial dipole. Atrial dipoles of the previously implanted leads ranged from 5 to 30 mm. Another 22 consecutive patients (14 M, 8 F, 80 +/- 7 years) in Group 2 received a Saphir 3 pacemaker with the related dedicated lead.

Results: P-wave amplitude measured by the same Pacing Sensing Analyzer (PSA) at the first implantation was 1.7 +/- 0.8 vs. 1.7 +/- 0.5 mV (P = NS) in groups 1 and 2 respectively. P-wave amplitudes measured at 1 month follow-up after replacement in Group 1 and at 1 month follow-up after implantation in Group 2 were 0.69 +/- 0.5 vs. 0.85 +/- 0.3 mV (P = NS) respectively. The percentage of atrial sensing at the same follow-up was 97 +/- 3 vs. 95 +/- 5% (P = NS) in groups 1 and 2 respectively.

Conclusions: Replacement of VDD pacemakers with the Saphir 3 model designed for a short dipole is safe and reliable when used in combination with previously implanted nondedicated leads.