Introduction: Acap Confirm (ACC) is a new algorithm offered by St. Jude Medical dual chamber pacemakers allowing for automatic atrial threshold determination. The aim of this study is to investigate the feasibility and short-term clinical and technical outcome of this test.
Methods: Patients scheduled for DDD pacemaker implantation (Zephyr XL DR 5820) were enrolled into this prospective evaluation. Set-up test ACC viability and manual step-down (0,4ms) atrial threshold test as well as automatic threshold testing by ACC were performed at implant, 2 weeks and 3 months after implantation. Participants who successfully completed both an automatic and manual capture thresholds test during follow-up were compared.
Results: Data from 79 patients (49M/30F, 70.4 ± 8.5 years old) were analyzed. Bipolar atrial leads (1882T and 1999T) were used. ACC activation rates are shown in the figure below. At 2 weeks and 3 months, threshold results from ACC and atrial manual capture test were: (0.63 ± 0.22 V versus 0.69 ± 0.22 V; r=0.94), and (0.59 ± 0.14 V versus 0.65 ± 0.17 V; r=0.87) respectively. The differences between automatic and manual measurements were =0.25V in all patients.
Conclusions: The reliability of ACC is relatively low over a short follow-up. Automatic atrial thresholds measurements (ACC) can be programmed in only 47% of patients at 3 months. There is a good correlation between automatic and manual atrial thresholds. However, long-term clinical outcomes are necessary to confirm these findings.