ECG Challenge: What Could Be the Underlying Cause of This Severe QTc Prolongation?

A 42-year-old female patient with a psychiatric history presented with recurrent near syncope episodes, revealing a significantly prolonged QTc (>750 msec) and baseline sinus bradycardia on ECG. The severe QTc prolongation was attributed to the side effect of high-dose methadone, a QTc-prolonging medication the patient had been on for her psychiatric conditions. The patient developed torsades de pointes (TdP) and was stabilized with intravenous magnesium sulfate. The alarming QTc prolongation necessitated an urgent medication reassessment. A multidisciplinary approach facilitated the patient's transition to a non-QT prolonging psychiatric medication, effectively mitigating the risk of further QTc prolongation, TdP, and potential fatality. This case underscores the critical need for vigilant monitoring and management of patients on QTc-prolonging medications, especially methadone, to preclude severe cardiac complications. [ABSTRACT FROM AUTHOR]