Non-vitamin K antagonist Oral anticoagulants in patients with Atrial High rate episodes (NOAH)

Atrial fibrillation (AF) is a common cause of stroke. Patients suffering from AF, if documented by an ECG, receive an antithrombotic therapy for stroke prevention consisting of oral anticoagulation treatment with vitamin K antagonists (VKAs) or non-vitamin K antagonist oral anticoagulants (NOACs). However, a large proportion of AF episodes remain undiagnosed (“silent AF”), and many of these patients present with a stroke as the first clinical sign of AF. Earlier initiation of anticoagulation could prevent such events.

Continuous monitoring of atrial rhythm by implanted devices could close this diagnostic gap. Modern pacemakers and defibrillators provide automated algorithms alerting to the occurrence of atrial high rate episodes (AHRE). There is evidence that stroke rate is increased in patients with AHRE. A sizeable portion of these patients develops AF over time. In these patients, AHRE can be considered as an early manifestation of AF. There is uncertainty about the optimal antithrombotic therapy in patients with AHRE.

NOAH – AFNET 6 is a prospective, parallel-group, randomized, open, double-blind, multi-center trial to evaluate the potential benefit of oral anticoagulation therapy in patients with AHRE, but without overt AF. The trial is to test whether treatment with the newly introduced NOAC edoxaban is superior to current therapy to prevent stroke, systemic embolism, or cardiovascular death in this patient group.

The investigator initiated trial will enroll 2.686 patients with AHRE and at least two stroke risk factors (CHA2DS2VASc Score of 2 or more). Patients are eligible for NOAH, if they have an implanted pace-maker or defibrillator with the feature of detection of AHRE and if their device documented AHRE with an atrial rate of at least 180 bpm and at least 6 min duration. Patients with overt AF are not eligible.

200 to 250 study centres in 15 European countries with adequate experience in the follow-up of implanted pacemakers or defibrillators in clinical routine will enroll the patients. The study participants will be randomized to either receiving edoxaban or receiving the current treatment consisting of antiplatelet therapy or no therapy depending on the cardiovascular risk.