Unmasking Hydroxychloroquine Cardiotoxicity in a Patient With Heart Failure and Chronotropic Incompetence

Chronic use of hydroxychloroquine can result in cardiomyopathy and conduction disturbances. Here, we describe a case of hydroxychloroquine cardiotoxicity in a patient with heart failure with preserved ejection fraction and severe chronotropic incompetence. (Level of Difficulty: Intermediate.).