Multigenerational thyroid hormone resistance due to THRβ mutation

This case emphasizes the rarity and clinical significance of RTH as a potential aetiology in refractory cardiac failure. Cardiologists should maintain a high index of suspicion for thyroid dysfunction in unexplained or treatment-resistant cardiomyopathy, particularly when associated with familial thyroid disorders or arrhythmias. Early diagnosis and a multidisciplinary approach involving endocrinology and cardiology are essential for improving outcomes and tailored therapeutic strategies for patients with RTH-related cardiomyopathy.