Progression of ECG in hydroxychloroquine overdose.

Hydroxychloroquine overdose is associated with myocardial toxicity and conduction disorders. We report a case of hydroxychloroquine overdose that demonstrated a rapid progressive intraventricular conduction delay and QT prolongation resulting in significant bradycardia and shock despite aggressive treatment. We describe the rare capture of abrupt abnormalities of this overdose in sequential electrocardiograms in the immediate hours post-ingestion.