BACKGROUND: An automatic capture (AC) algorithm adjusts ventricular pacing output to capture the ventricle while optimizing output to 0.5 V above threshold. AC maintains this output and confirms capture on a beat-to-beat basis in bipolar and unipolar pacing and sensing. OBJECTIVE: To assess the AC algorithm and its impact on device longevity. METHODS:Patients implanted with a pacemaker were randomized 1:1 to have the AC feature on or off for 12 months. Two threshold tests were conducted at each visit- automatic threshold and manual threshold. Average ventricular voltage output and projected device longevity were compared between AC on and off using nonparametric tests. RESULTS:Nine hundred ten patients were enrolled and underwent device implantation. Average ventricular voltage output was 1.6 V for the AC on arm (n = 444) and 3.1 V for the AC off arm (n = 446) (P < 0.001). Projected device longevity was 10.3 years for AC on and 8.9 years for AC off (P < 0.0001), or a 16% increase in longevity for AC on. The proportion of patients in whom there was a difference between automatic threshold and manual threshold of <or=0.5 V through follow-up was 99.0% (95% CI: 98.6, 99.3). The average difference between automatic threshold and manual threshold was 0.07 V (P = 0.002). CONCLUSIONS: This study showed that automatic threshold testing at follow-up provided comparable information to manually measured threshold testing. AC provided a significant increase in projected device longevity compared to standard programing.
RCT Entities:
BACKGROUND: An automatic capture (AC) algorithm adjusts ventricular pacing output to capture the ventricle while optimizing output to 0.5 V above threshold. AC maintains this output and confirms capture on a beat-to-beat basis in bipolar and unipolar pacing and sensing. OBJECTIVE: To assess the AC algorithm and its impact on device longevity. METHODS:Patients implanted with a pacemaker were randomized 1:1 to have the AC feature on or off for 12 months. Two threshold tests were conducted at each visit- automatic threshold and manual threshold. Average ventricular voltage output and projected device longevity were compared between AC on and off using nonparametric tests. RESULTS: Nine hundred ten patients were enrolled and underwent device implantation. Average ventricular voltage output was 1.6 V for the AC on arm (n = 444) and 3.1 V for the AC off arm (n = 446) (P < 0.001). Projected device longevity was 10.3 years for AC on and 8.9 years for AC off (P < 0.0001), or a 16% increase in longevity for AC on. The proportion of patients in whom there was a difference between automatic threshold and manual threshold of <or=0.5 V through follow-up was 99.0% (95% CI: 98.6, 99.3). The average difference between automatic threshold and manual threshold was 0.07 V (P = 0.002). CONCLUSIONS: This study showed that automatic threshold testing at follow-up provided comparable information to manually measured threshold testing. AC provided a significant increase in projected device longevity compared to standard programing.