9. Pacemakers: Clinical Results, Practical Aspects and Late-Break Clinical Trials: 9.3 Effects of Ventricular Automatic Capture on Pacemaker Longevity Free

Ventricular Automatic Capture (VAC) is thought to increase device longevity by reducing the pacing safety margin. We evaluated the effect of the GUIDANT VAC technology on longevity in dual chamber rate responsive pacemakers.

87 patients, 69.8±13.6 years indicated for DDDR pacing received an INSIGNIA I Ultra DR pacemaker with VAC technology and had a follow-up after 3 months (3 MFU). 29 different lead types from 9 manufacturers were used. Measured ventricular pacing threshold, lead impedance, %A/V-paced, and average pacing rate were used to calculate expected device longevity. Comparisons were made with the assumption that the VAC-Off ventricular amplitude would have been programmed to 2x the 3-MFU measured threshold, but at least 2.5V.

Atrial: % pacing: 42±35, lead impedance: 510.7±188.2W, pacing voltage: 2.9±0.9V. Ventricular: % pacing 80±32, lead impedance: 649.9±218.6W, pacing voltage: 1.2±0.3V. Ventricular pacing amplitude using VAC was 1.2±0.3V and without VAC 2.5±0.2V (p<0.01). There was a significant increase in projected device longevity between VAC-On (7.2±0.7 years) and VAC-Off (6.8±0.8 years) (p<0.01).

VAC may result in increased battery longevity over a wide range of ventricular leads.