LA-HCM Study : Rivaroxaban for Antithrombotic Prevention in Hypertrophic Cardiomyopathy Patients With Abnormal Left Atrial Strain.

Inclusion Criteria: 1. 40 - 80 years of age 2. 50 and 120 kg of weight 3. In sinus rhythm 4. Prior confirmed diagnosis of "primary" hypertrophic cardiomyopathy 5. Left Atrial reservoir strain measured ≤20% (corelab confirmation) 6. Signature of an informed consent 7. Highly effective contraceptive methods for women of childbearing potential from at least 14 days prior to start treatment, throughout the study treatment period, and until at least 4 weeks after the last dose of study medication Exclusion Criteria: 1. Secondary hypertrophic cardiomyopathy (aortic stenosis, hypertension, amyloidosis and all phenocopies…) 2. Signs of heart failure 3. Hospitalization 4. Uncontrolled blood pressure 5. Creatinine clearance \<30 mL/min (Cockcroft) 6. Severe liver dysfunction, cirrhosis Child B or C 7. Any anticoagulation therapy in the 15 days prior to enrollment 8. Any cardiac surgery in the 30 days prior to enrollment 9. Documented atrial arrhythmia 10. Any major bleeding in the 90 days prior to enrollment 11. Need to be on dual antiplatelet therapy (aspirin \>100 mg daily and a P2Y12 inhibitor, i.e. clopidogrel, ticagrelor, prasugrel…). 12. Contraindication for a brain magnetic resonance imaging exam 13. Known hypersensitivity or others contraindications to Rivaroxaban (refer to contraindications) 14. Ischemic stroke or intracranial hemorrhage in the 30 days prior to enrollment 15. Active endocarditis at the time of enrollment 16. Concomitant combined strong P-gp and CYP3A4 inducers or inhibitors 17. Active cancer or life expectancy less than 3 years 18. Non-compliant 19. Participation in another interventional clinical trial 20. Protected person (adults legally protected (under judicial protection, guardianship or supervision), person deprived of their liberty, pregnant woman, lactating woman or planning pregnancy during the study period and minor) 21. Absence of coverage by a social security scheme