In a study looking at ZIO®XT Patch use in outpatients with clinical indications for monitoring (15% of whom had syncope), of the 60% of patients who had an arrhythmia detected, 30% had their first arrhythmia and 51% had their first symptom-triggered arrhythmia occur after the initial 48-hour period. Mean time to first arrhythmia was 1.7 days (median 0.8) and mean time to first symptomatic arrhythmia was 3.0 days (median 2.1).