Annals of Internal MedicineHydroxychloroquine Cardiomyopathy—A Case Series and Review of the Literature

⚠️ Rare but High Risk Safety Event

A retrospective single-center series identified 13 patients with endomyocardial biopsy-proven hydroxychloroquine cardiomyopathy over 8 years. Patients (86% female, mean age 62) had average cumulative HCQ exposure of approximately 1,868 g, with outcomes ranging from full recovery to death after advanced HF interventions.

Clinical Considerations:

• Average HCQ treatment duration was 14 years; presentations included dyspnea, syncope, ventricular tachycardia, and acute decompensated heart failure.
• Of 13 patients after HCQ discontinuation, 3 died, 2 fully recovered LV function, 3 improved clinically, and 5 had persistent dyspnea.
• Diagnostic clues include patchy noncoronary late gadolinium enhancement on cMRI plus myocyte vacuolization and curvilinear bodies on biopsy.
• Differential includes amyloidosis, sarcoidosis, Fabry disease, and hypertrophic cardiomyopathy, given overlapping imaging and histopathologic features.

Practice Applications:

• Consider HCQ cardiomyopathy in long-term HCQ users presenting with unexplained heart failure or pulmonary hypertension.
• Recognize conduction abnormalities and progressive heart block as early signals.
• Integrate ECG, TTE, and cMRI as screening tools, with endomyocardial biopsy for diagnostic confirmation.
• Monitor patients on long-term HCQ for cardiac symptoms, particularly at higher cumulative doses.