P4772Role of anticoagulation in patients with subclinical AF and its association with cardiovascular events: a SILENT sub study

Background

Atrial fibrillation (AF) is a well-established thromboembolic event risk factor. Episodes of subclinical AF (SCAF) recorded in implantable electronic cardiac devices (IECD) have been related to clinical AF and increased risk of stroke. However, there is no scientific evidence regarding the role of anticoagulation in this population. Objective: Our objective is to assess the association of SCAF with clinical AF and rate of systemic thromboembolic events, in a short-term follow-up.

Methods

This is a sub-study of SILENT, a prospective, randomized, unicentric study which included patients with sinus rhythm, IECD, with CHA2DS2-VASc ≥2, without previous history of AF. Patients were randomized to the Intervention Group and to the Control Group in the 1: 1 ratio. Patients of the Intervention Group with SCAF episodes (>6 min) received anticoagulation, as well as those with clinical AF in both groups. The primary end point was systemic thromboembolic phenomena and the secondary endpoints were SCAF rate, total and cardiovascular mortality, cardiovascular hospitalization and bleeding.

Results

A total of 758 patients were evaluated, with a mean age of 72.81 years (± 9.73), of which 461 (60.8%) were female. The mean follow-up was 19.59±4.24 months. Baseline characteristics were similar in both groups. Only 3 patients presented the primary outcome (two of them from Intervention Group). There were 16 deaths (2,1%) and 44 cardiovascular hospitalizations (5,8%), with no difference between groups. Atrial high rate episodes (AHRE) and clinical AF were more prevalent in Control Group, leading to an equal rate of anticoagulation between groups. Clinical AF was statistically associated to previous atrial high rate episodes of any duration (p=0.001) and correlated with SCAF (p<0.01 and R: 0,60) previously recorded in the device.

Conclusion

This sub study showed that, in a short term follow-up, SCAF has a good correlation with clinical AF occurrence with low rate of thromboembolic events. The Silent study will evaluate in an extended population the role of anticoagulation, in the long term.

Acknowledgement/Funding

None