Positive predictive value of device-detected atrial high-rateepisodes at different rates and durations: an analysis from ASSERT

BACKGROUND Pacemakers can automatically identify and catalogatrial high-rate episodes (AHREs). While most AHREs represent true atrial tachyarrhythmia/atrial fibrillation (AT/AF), a review of stored electrograms suggests that a substantial proportion do not. As AHREs may lead to the initiation of oral anticoagulation, it iscrucial to understand the relationship between AHREs and true AT/AF.OBJECTIVE To compare the positive predictive value of AHREs forelectrogram-confirmed AT/AF for various atrial rates and episodedurations.METHODS By using data from 2580 patients who participated in the ASymptomatic atrial fibrillation and Stroke Evaluation in pacemakerpatients and the AF Reduction atrial pacing Trial, all AHREs 6 minutes and 190 beats/min with available electrograms were reviewed to determine whether they represented true AT/AF. The positive predictive value of these AHREs was assessed for episodedurations of 6 minutes, 30 minutes, 6 hours, and 24 hours at atrial rates of 190 and 250 beats/min.RESULTS Of 5769 AHREs 6 minutes and 190 beats/min, 82.7% were true AT/AF and 17.3% were false positives (predominantly due to repetitive non–re-entrant ventriculoatrial synchrony).False positives dropped to 6.8%, 3.3%, and 1.8% when the threshold duration was increased to 30 minutes, 6 hours, and 24 hours, respectively. Increasing the threshold heart rate to 250beats/min added little to the positive predictive value when longerthreshold durations were used.CONCLUSIONS By using a cutoff of 6 minutes and 190 beats/min, the rate of false-positive AHREs is 17.3%, making physicianreview of electrograms essential. For AHREs lasting 6 hours, therate of false positives is 3.3%, making physician review less crucial.