Rivaroxaban for Stroke Prevention in Hypertrophic Cardiomyopathy Without Atrial Fibrillation and With Impaired Left Atrial Reservoir Strain: Design and Rationale of the LA-HCM Randomized Trial

BACKGROUND: Current stroke prevention strategies in hypertrophic cardiomyopathy (HCM) rely on the detection of atrial fibrillation (AF), although thromboembolic events may occur before arrhythmia is documented. These observations support atrial cardiomyopathy as the substrate for thrombogenesis and highlight the need for imaging-guided risk stratification. Left atrial reservoir strain (LARS), derived from speckle-tracking echocardiography, detects atrial dysfunction earlier than left atrial enlargement and has been associated with AF and thromboembolic events. The LA-HCM trial evaluates whether rivaroxaban reduces thromboembolic events in patients with HCM, sinus rhythm, no documented AF, and impaired LARS. LA-HCM is a prospective, multicentre, randomized, open-label trial with blinded endpoint adjudication (PROBE design), sponsored by Rennes University Hospital and conducted in 17 French centres. A total of 532 adults with HCM, sinus rhythm, no documented AF, and core-laboratory-confirmed LARS ≤20% are randomized 1:1 to rivaroxaban or standard care. Participants are followed for 24 months. The primary endpoint is the composite of all-cause death, myocardial infarction, ischemic stroke-including newly detected silent cerebral infarction on paired baseline and 24-month brain MRI-and systemic embolism at 24 months. LA-HCM tests whether rivaroxaban improves outcomes in a population with HCM, no documented AF, and impaired LARS. It evaluates a LARS-based treatment-allocation strategy but is not designed to validate the predictive utility or optimal threshold of LARS.