The aim of this prospective, monocentric, non-randomized trial is to investigate the impact of catheter ablation of atrial tachyarrhythmias on the ABC-stroke and ABC-bleeding risk scores. Participants planned for first catheter ablation for symptomatic atrial tachyarrrhythmias (atrial fibrillation, atrial flutter) will be enrolled. Serial blood samples will be collected before and 3, 6 and 12 months after catheter ablation to calculate the ABC scores as well as the traditional bleeding and stroke risks. Following catheter ablation, continuous rhythm monitoring will be achieved using an insertable monitor or an implanted atrial lead of a cardiac implantable electronic device. Additionally, heart rate monitoring via photoplethysmography using a smartwatch and/or smartphone is performed for a period of six months. Data are analyzed for differences in ABC scores before and after ablation in relation to possible AF/AT recurrences. Furthermore, we are going to compare the sensitivity and specificity of different follow-up modalities post ablation. The monitoring via ICM (gold standard) is compared to smartwatch-based monitoring alone, versus smartphone-based monitoring alone or a combination of both for AT/AF recurrences.