Background: Pacemaker treatment of known trigger mechanisms for atrial tachyarrhythmias(AT) and atrial fibrillation(AF) has shown reduction in the incidence of AF. A new arrhythmia management device,which included storage of AT/AF(for tailoring treatment) and three prevention algorithms and one for treatment, was examined in order to identify the influence on arrhythmia episodes over a 12-month follow-up(FU) period. Methods: Twenty-three consecutive patients with known tachybradyarrhythmias were examined. Seven patients had to be excluded(two outliers, four developed permanent AF, one had no detection algorithm turned on at implantation). The remaining 16 patients showed 2723 episodes(675 treated episodes) for evaluation of the effect on episodes/month/patient(e/m/p), treatment success, duration of episodes, circadian distribution and quality of life. Results: The AT/AF e/m/p were reduced from 37±102 e/m/p at 1-month FU to 16±48e/m/p at 3-month FU, 15±48 e/m/p at 6-month FU and 10±28e/m/p at 12-month FU(p< 0.05), according to fewer subjective symptoms. Treatment success remained stable during the observation period(29-40%). Only minor changes in the duration of episodes and the distribution of start times were observed. Conclusion: Tailoring treatment by the pacemaker examined with several prevention and treatment algorithms reduces e/m/p and might be a promising supplement in the treatment of selected patients with known AT/AF and bradycardia. Background: Pacemaker treatment of known trigger mechanisms for atrial tachyarrhythmias (AT) and atrial fibrillation (AF) has shown reduction in the incidence of AF. A new arrhythmia management device, which includes storage of AT / AF (for tailoring treatment) and three prevention algorithms and one for treatment, was examined in order to identify the influence on arrhythmia episodes over a 12-month follow-up (FU) period. Methods: Twenty-three consecutive patients with known tachybradyarrhythmias were examined. Seven patients had to be excluded ( two outliers, four developed permanent AF, one had no detection algorithm turned on at at implantation). The remaining 16 patients showed 2723 episodes (675 treated episodes) for evaluation of the effect on episodes / month / patient (e / m / p) Results: The AT / AF e / m / p were reduced from 37 ± 102 e / m / p at 1-month FU to 16 ± 48 e / m / p at 3-month FU, 15 ± 48 e / m / p at 6-month FU and 10 ± 28e / m / p at 12-month FU (p <0.05), according to fewer subjective symptoms. Treatment successful remained stable during the observation period (29-40%). Only minor changes in the duration of episodes and the distribution of start Conclusion: Tailoring treatment by the pacemaker examined with several prevention and treatment algorithms reduces e / m / p and might be a promising supplement in the treatment of selected patients with known AT / AF and bradycardia.