More and more frequently, silent atrial fibrillation (AF) events are detected in intracardiac electronic device (ICED) memory (“infraclinical AF” or “had atrial high rate events AHRE”). In MOST trial, AHRE were seen in almost 50% of patients treated for sinus node dysfunctionand were associated with an increased risk of stroke (1.69% per year if CHADS score>2) in ASSERT study. Nevertheless currently there are no antithrombotic recommendations for these patients. We tried to describe the different therapeutic alternatives in usual practice.

Materials and methods: We started a prospective registry of patients with silent AF detected in DDD or CRT PMK/ICD of all constructors. Inclusion criteria were: age > 18 y, AHRE diagnosed by device algorithms and > 6 minutes duration, confirmation by atrial endocavitary electrogram. We excluded patients with a previous history of “clinical AF”or valvular AF. The antithrombotic strategy was decided by the referent physician.

From November 2013 to May 2014, 43 patients were included. The median age was 77 years old. 26 patients (60%) had a DDD PMK (10 for sinus node dysfunction (23%), 15 for AV block (35%), 1 for obstructive CMP), 10 patients (23%) a DDD ICD (6 (14%) for primary prevention and 4 (9%) for secondary prevention) and 7 patients a CRT-D (16%). The median CHADS2 score was 2, the median CHADS2VASCscore was 4 (mean respectively 2.36 and 3.56): 5 patients had a history of embolic event (11%). Only 28 patients (65%) were on anticoagulation therapy: 15 (35%) antivitamin K and 13 (30%) new oral anticoagulants. 10 patients (23%) received aspirin and 5 patients the association aspirin/clopidogrel (11%). 2 patients did not receive any antithrombotic treatment. There were no difference in CHADS and CHADSVASC scores between patients treated or not with anticoagulants (respectively p=0.21 and p =0.57)

Most of patients in this study received an anticoagulation therapy as a stroke prevention strategy.