Background: Second-generation cryoballoon (CB2)-based pulmonary vein isolation (PVI) has demonstrated encouraging clinical results for the treatment of paroxysmal atrial fibrillation (AF) and persistent AF. However, rhythm follow-up after PVI is mainly based on Holter electrocardiography of limited duration. Objective: The purpose of this study was to assess the real AF burden following CB2-based PVI in patients with implanted cardiac devices. Methods: A total of 670 consecutive patients underwent CB2-based PVI at 3 electrophysiology centers. In 66 patients (9.9%), an implantable cardiac device with continuous monitor function was independently implanted before the procedure (device group). This patient cohort was compared to propensity score-matched patients without cardiac devices (n = 66; control group). Results: A total of 254 of 258 PVs (98.4%0 in the device group were successfully isolated using only CB2. Postprocedural device interrogation found no device or lead malfunction related to the procedure. Periprocedural complications were registered in 7 of 66 patients (11%) in the device group and in 6 of 66 patients (9%) in the control group (P =.770). Phrenic nerve palsy occurred in 6 of 66 patients (9%) in the device group) and in 2 of 66 patients (3%) in the control group) (P =.274). Clinical success in terms of freedom from AF recurrence after a 1-year follow-up period was 63.8% (95% confidence interval 53–77) in the device group and 77.3% (95% confidence interval 68–88) in the control group (P =.038). In the device group, AF/AT burden decreased from 41.8% ± 35.0% before the procedure to 10.2% ± 22.4% after 1 year (P <.0001). Conclusion: CB2-PVI seems safe and feasible in patients with an implanted cardiac device. A significantly higher AF/AT burden was seen in patients with an implanted cardiac device compared to a control group.