First known case of a potentially deadly heart rhythm disturbance induced by chloroquine therapy for COVID-19 reported

A patient who met many of the published safety guidelines for chloroquine therapy against COVID-19 was observed to have a very abnormal ECG pattern after treatment began, leading to multiple episodes of torsade de pointes (TdP), a life-threatening arrhythmia in which the lower chambers of the heart beat out of sync with the upper chambers. Her condition was resolved after chloroquine was discontinued, investigators report in Heart Rhythm.