Progression of new onset to established persistent atrial fibrillation: an implantable device-based analysis with implications for clinical classification of persistent atrial fibrillation.

INTRODUCTION: The temporal patterns of onset of persistent atrial fibrillation (AF) recurrences leading to established persistent AF is currently unknown.
METHODS: Three hundred thirty patients with a history of paroxysmal AF and bradycardia (mean age, 70 ± 10 years; 61% male) with implanted pacemakers that automatically recorded the cumulative daily atrial tachyarrhythmia (AT) burden were included in the analysis. Persistent AF was defined as device data showing ≥7 consecutive days with ≥23 h of AT. We analyzed the pattern and duration of persistent AF recurrences and time to each persistent AF episode recurrence.
RESULTS: Seventy-eight patients (24%) developed their first persistent AT/AF after 147 ± 149 days. Follow up ranged from 14 to 499 days. Median AF burden in the week prior to persistent AF was 3.5 h/day. Fifty-four patients (16%) had a minimum of 180 days follow up after initial detection of persistent AF. Three of 54 patients (6%) immediately developed established AF; 32 of 51 patients (63%) returned to sinus rhythm but then had a second persistent AF event. These 32 patients had a minimum of 90 days follow up and 25 of these 32 patients (78 %) had a third persistent AF event. Time to recurrence analysis showed progressive abbreviation in persistent AF onset. The median durations of the first, second, and third persistent AF events were 16, 13, and 17 days, respectively.
CONCLUSIONS: (1) The time to first, second, and third persistent AF recurrences progressively decreases with a high likelihood of established persistent AF within 9 months of onset. (2) These data support intermittent but frequent AF monitoring for the detection of persistent AF recurrences to assess the efficacy of rhythm control interventions.