Torsade de pointes in a patient with complex medical and psychiatric conditions receiving low-dose quetiapine

Objective: Describe potential cardiac complications of low-dose quetiapine and other atypical antipsychotic drugs. Method: We present a case report of a 45-year-old Black woman with multiple medical and psychiatric problems taking low-dose quetiapine. Results: Coincident with a generalized seizure, the patient developed 'ventricular fibrillation'. She was countershocked with restoration of normal sinus rhythm. The initial electrocardiogram showed QT interval prolongation. Shortly thereafter, classical torsade de pointes appeared, lasted 10 min, and resolved spontaneously. Hypomagnesemia was present. A cardiac electrophysiologist was concerned that the very slow shortening of the prolonged QTc interval after magnesium replacement implicated quetiapine as a risk factor for QTc interval prolongation and torsade de pointes. A psychosomatic medicine consultant asserted that the fragmented medical and psychiatric care almost certainly contributed to the patient's medical problems. We discuss other cases of QT interval prolongation by newer antipsychotic drugs and previous reports by our group concerning the association of psychotropic drugs, QT interval prolongation, and torsade de pointes. Conclusion: Atypical antipsychotic drug administration, when accompanied by risk factors, may contribute to cardiac arrhythmias including torsade de pointes.