LETTERS TO THE EDITOR Cardiac toxicity secondary to long term treatment with chloroquine

Chloroquine is frequently used to treat systemic autoimmune diseases, such as systemic lupus erythematosus (SLE). With long term treatment, associated toxicity is well known, with retinopathy been the most common complication. Other chronic complications include skin disorders (hyperpigmentation), blood dyscrasias, corneal deposits, encephalopathy, neuropathy, myopathy, and impairment of auditory function. Cardiac complications, such as conduction disorders, myocardial hypertrophy, and restrictive cardiomyopathy, have also been reported in long term treatment. Nevertheless, this problem is underappreciated. We describe a patient with SLE who developed a complete heart block and a restrictive cardiomyopathy owing to chronic treatment with chloroquine.