Hydroxychloroquine and Chloroquine Induced Cardiomyopathy: A Concise Review

Hydroxychloroquine and Chloroquine are commonly used for the treatment of malaria and autoimmune conditions. Most recently, hydroxychloroquine has been implicated in the treatment armamentarium of Severe acute respiratory syndrome (SARS) caused by SARS-associated coronavirus-2. A rare, underreported side effect of hydroxychloroquine and chloroquine is cardiotoxicity. The cardiomyopathy occurs as a result of inhibition of lysosomal enzymes causing lysosomal dysfunction and intra-cellular accumulation of metabolic byproducts in the myocardium, leading to hypertrophy with or without restrictive physiology and resultant conduction abnormalities. Based on our review of 57 reported cases of hydroxychloroquine or chloroquine induced cardiomyopathy, dyspnea was the most common associated symptom. The most common rhythms seen on EKG were as follows: complete heart block (18.75%), right bundle branch block (RBBB) (18.75%). The most common findings on echocardiography were left ventricular hypertrophy (LVH) (54%), systolic dysfunction (48%) and diastolic dysfunction (32%). A definitive diagnosis is established by endomyocardial biopsy which demonstrates the presence of curvilinear inclusion bodies. The outcome following cessation of the offending agent ranges from complete reversal in 45% of the cases to continued progression with need for cardiac transplantation or even death in 17.5% of the cases.