Hydroxychloroquine-induced cardiomyopathy: role of cardiac magnetic resonance for the diagnosis and follow-up of a very rare entity-a case report.

Background: Hydroxychloroquine (HCQ) is a disease-modifying antirheumatic used in rheumatological diseases such as systemic lupus erythematosus. Long-term exposure to HCQ results in drug accumulation and predisposes to adverse effects. Case summary: We present the case of a 45-year-old woman with long-term treatment with HCQ who presented to the Emergency Department with acute heart failure. Transthoracic echocardiogram, previously normal, showed severe biventricular hypertrophy and biventricular systolic dysfunction. Cardiac magnetic resonance (CMR) confirmed the previous findings and showed elevated native T1 and T2 values, elevated extracellular volume, and extensive mid-wall late gadolinium enhancement (LGE). Infiltrative cardiomyopathy was suspected, and endomyocardial biopsy performed. Light microscopy showed myocyte hypertrophy and vacuolar change and absence of lymphocytic inflammatory infiltrates. The diagnosis of HCQ-induced cardiomyopathy was established, and the drug was withdrawn. A CMR performed 1 year later showed normal systolic function of both ventricles and normalization of T2 values, reflecting resolution of myocardial oedema. However, severe hypertrophy, elevated native T1 values, and LGE persisted. Discussion: Our case shows that although discontinuation of the drug stops the progression of the disease, established myocardial structural damage persists. Early diagnosis of this entity is therefore essential to improve prognosis.