Background/Purpose: Antimalarials (AM) are currently recommended for the management of all patients with systemic lupus erythematosus (SLE) without specific contra-indications. Their main adverse effect is retinal damage, however heart disease has been described in isolated cases. The aim of this study is to describe a series of patients with AM-induced cardiomyopathy (AMIC) in a defined lupus cohort.

Methods: Patients attending the Lupus Clinic and diagnosed with definite [based on endomyocardial biopsy (EMB)] and possible [based on cardiac magnetic resonance (CMR) and other investigations] AMIC were included.

Results: Eight female patients (age 62.5 years, disease duration 35 years, AM use duration 22 years, all medians) were diagnosed with AMIC in the past two years during evaluation for cardiovascular disease. Diagnosis was based on EMB in three, showing extensive vacuolation of the cardiomyocytes and intracytoplasmic myelinoid and curvilinear bodies. CMR was highly suggestive of AMIC in another four patients with features including ventricular hypertrophy and/or atrial enlargement and late gadolinium enhancement in a non-vascular pattern. Another patient was diagnosed based on complete atrioventricular block, left ventricular and septal hypertrophy along with AM-related ocular toxicity. Clinical presentation was that of congestive heart failure in two patients and syncope in one; investigations in the remaining patients were initiated based on abnormal cardiac troponin I (cTnI) and brain natriuretic peptide (BNP). All patients had abnormal cTnI and BNP whereas 7/8 also had chronically elevated creatine phosphokinase (CPK). Right bundle branch block (RBBB) was present in 4 patients, while two of them also had left anterior fascicular block (LAFB). Apart from atrial and/or ventricular hypertrophy, all patients had interventricular septum (IVS) hypertrophy and moderate diastolic dysfunction. During follow-up, one patient died due to refractory heart failure; she was complicated with septic shock during ICU hospitalization. In 5/7 patients, hypertrophy regression and a steady decrease of heart biomarkers was observed. Coronary angiography was performed in 6/8 patients and was normal. Daily hydroxychloroquine dose exceeded 6.5mg/kg in three patients. Details are shown in Table 1.

Conclusion: AMIC is a rare, probably under-recognized, complication of prolonged AM treatment. It usually presents as a hypertrophic, restrictive cardiomyopathy particularly affecting IVS with or without conduction abnormalities. Heart-specific biomarkers and serum CPK may be of value for early diagnosis.