AHREs, currently de ned as episodes of at least 5 min of atrial tachyarrhythmias/AF with an atrial rate >180 beats/min, are usually asymptomatic, discovered during routine device follow-up, and classi ed in terms of duration of the single episode or time spent in atrial tachyarrhythmias during a day (from minutes to Although temporal cutoffs for detection and storage of AHRE data as short as 30 to 60 s have been used, the diagnostic accuracy is reliable when episodes $ 5 min in duration are considered, since, using this cutoff, the appropriateness in AF detection is 95%, minimizing the risk of over-sensing due to detection of artifacts caused by myopotentials or other sources of electrical Individual patient analysis of electrograms corresponding to AHREs is clinically indicated to exclude artifacts or other causes of inappropriate detection of atrial tachyarrhythmias or AF. 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). 