Platelet-activation and Optimal Inhibition in Patients With Atrial Fibrillation Undergoing Left Atrial Appendage Occlusion

Inclusion Criteria: * The subject is aged 18 years or older * The subject is accepted/scheduled for left atrial appendage occlusion * The subject has a CHA₂DS₂-VASc Score ≥2 (male) or ≥3 (female) * The subject or legal representative is able to understand and is willing to provide written informed consent to participate in the trial. Exclusion Criteria: * Unable or unwilling to return for required follow-up visits and examinations * Mechanical heart valves or valvular disease requiring surgery or interventional procedure * Ongoing major bleeding or complicated or recent (\<72hours) major surgery * Known large oesophageal varices or decompensated liver disease (unless a documented positive opinion of a gastro-enterologist) * Severe thrombocytopenia (\<50,000/ml) * High likelihood of being unavailable for follow-up or psycho-social condition making study participation impractical. * Woman with child bearing potential who do not use an efficient method of contraception. * Positive serum or urine pregnancy test for woman with child bearing potential * Pregnancy or within 48 hours post-partum * unsuitable LAA anatomy for occlusion or thrombus in the LAA at the time of procedure * contraindications or unfavourable conditions to perform cardiac catheterization or transesophageal echocardiography (TEE) * atrial septal malformations, atrial septal defect or a high-risk patent foramen ovale that may cause thrombo-embolic events * atrial septal defect repair or closure device or a pa…