Acquired long QT syndrome results from secondary causes and can be caused by more than 100 non-antiarrhythmic drugs. Cardiac arrest due to Torsades de pointes induced by drugs causing prolonged QT syndrome is a rare but potentially fatal event, even in hospitals. The case of a 47-year-old patient diagnosed with non-Hodgkin lymphoma admitted to the hematology department of the Dr. Gustavo Aldereguía Lima University General Hospital in Cienfuegos is presented. The patient had been previously treated with anthracyclines and developed episodes of palpitations and syncope later. The treatment included monitoring the patient, avoiding other QT prolonging agents and administrating magnesium sulfate and potassium chloride with a proper maintenance of the fluid and acid-base balance. The presentation of this case aims at motivating interest in new reports on the subject and establishing a direct causal relationship through the evidence provided by new experiences
