Electrograms of AHREs correspond to intracardiac electrograms recorded from right atrial appendage or right atrium so a diagnosis of tachyarrhythmias can easily be made through analysis of tracings recorded in the device s memory.157 After detection of AHREs by CIEDs, conventional Holter or other ECG long-term recordings (ie, patient-operated devices) can be considered in speci c cases (eg, unavailable electrograms or unclear diagnosis at device electrograms analysis). The possibility of continuous monitoring of AF through implanted devices has led to new terms, such as AF burden, de ned as the overall time spent in AF during a speci ed period of time,368,376-378 and subclinical AF, corresponding to episodes of atrial tachyarrhythmias with duration between 5 min and 24 h, detected by a CIED in patients without clinical history or clinical symptoms of AF.367,370-372 The prevalence of AHRE, often reported as AF burden, among patients implanted with CIEDs varies, depending on underlying heart disease, periods of observation, and above all previous history of clinically overt atrial tachyarrhythmias, including AF. In the ASSERT study, subclinical atrial tachyarrhythmias with at least 6 min duration were detected within 3 months in approximately 10% of patients implanted with a CIED.371 During a follow-up period of 2.5 years, additional subclinical atrial tachyarrhythmias occurred in approximately 25% of patients, and around 16% of those who had subclinical atrial tachyarrhythmias developed symptomatic AF.371 Considering these ndings, as well as data from the literature reported in e-Table 20, there is evidence that AHREs with a duration > 5 to 6 min are common in patients implanted with CIEDs. 