Background/Purpose: Antimalarial-induced cardiomyopathy (AMIC) is a hypertrophic cardiomyopathy with conduction system disorders, cardiac biomarker abnormalities and a short-term mortality of 45%. Data on the reversibility of the disease are sparse. The aim of this study is to assess the evolution of AMIC in the long term in patients with systemic lupus erythematosus (SLE).

Methods: Ten patients with SLE who developed AMIC were analyzed (mean age at diagnosis 63±8.7 years, mean disease duration 32.8±12.7 years, mean antimalarial treatment duration 22.4±9.4 years). Diagnosis was confirmed by myocardial biopsy in three patients (extensive cardiomyocyte vacuolation, intracytoplasmic myelinoid and curvilinear bodies) and considered probable in another seven cases based on a combination of abnormal cardiac biomarkers (high sensitivity troponin I and brain natriuretic peptide, BNP), hypertrophic cardiomyopathy (based on cardiac magnetic resonance, CMR) and the exclusion of other causes (coronary artery disease, uncontrolled hypertension). Other types of idiopathic hypertrophic cardiomyopathy and/or Anderson-Fabry cardiomyopathy were excluded by genetic testing.

Results: Mean follow-up after AMIC diagnosis was 23.7±10.7 months; antimalarials were discontinued in all patients, while diuretics were commenced or intensified in three. The evolution of structural, functional and conduction system abnormalities as well as the cardiac biomarkers are shown in the table.

All four patients with severe arrhythmias had a right bundle branch block and two of them had bifascicular block for years before the arrhythmia. The median reduction of troponin I (7/10 patients) was 29.7% at one year, 53.1% at two years and 74.1% at three years (compared to baseline). The median reduction of BNP (6/10 patients) was 49% at one year, 81.3% at two years and 68.8% at three years (compared to baseline).

Conclusion: Recovery of the structural (left ventricular and septal hypertrophy, left atrium enlargement), functional (systolic and diastolic dysfunction) and biochemical variables (troponin I, BNP) occurs in most patients with AMIC but this is slow and often incomplete even after two years. Conduction abnormalities may still develop many months after drug withdrawal.

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ACR Meeting Abstracts - https://acrabstracts.org/abstract/antimalarial-induced-cardiomyopathy-outcome-in-10-patients/