IntroductionAtrial high-rate episodes (AHREs) are associated with an increased risk of developing atrial fibrillation and thromboembolism. The characteristics of ‘real world’ patients developing AHREs are poorly known.MethodsWe included 496 consecutive patients with cardiac implantable electronic devices (CIEDs). Primary endpoint was occurrence of AHREs, defined as > 175 bpm and lasting > 5 min, in a median follow-up of 16.5 (IQR 3.9–38.6) months (1082.4 patient-years). We also tested the predictive value of clinical risk scores for AHREs.ResultsMean age was 68.8 ± 14.0 years, and 35.5% were women; AHREs were recorded in 173 patients [34.7%, 16.0%/year, 95% confidence interval (CI) 13.7–18.6]. Multivariable Cox regression analysis showed that age [hazard ratio (HR) 1.020, 95% CI 1.004–1.035, p = 0.011], prior AF (HR 3.521, 95% CI 2.831–5.206, p < 0.001), white cell count (HR 1.039, 95% CI 1.007–1.072, p = 0.016) and high C reactive protein (CRP; HR 1.039, 95% CI 1.021–2.056, p = 0.038) were independently associated with AHREs. ROC curve analysis showed that the APPLE score (C statistic 0.53, 95% CI 0.48–0.59; p = 0.296) ALARMEc score (C statistic 0.51, 95% CI 0.44–0.57; p = 0.810) were non-significantly associated with AHRE. Similar results were obtained for CHADS2 and CHA2DS2VASc scoreConclusionAHREs are common in CIEDs patients, with age, prior AF, inflammatory markers (high CRP, white cell count) being factors associated with AHREs onset. Clinical risk scores showed limited value for AHREs prediction in this cohort.Electronic supplementary materialThe online version of this article (10.1007/s00392-018-1244-0) contains supplementary material, which is available to authorized users.