Electrocardiographic changes and clinical outcomes in quetiapine poisoning: a retrospective cohort study

Introduction Quetiapine has a three-ringed chemical structure similar to that of tricyclic antidepressants (TCA). Several electrocardiogram (ECG) findings, including prolonged QRS intervals, high R wave amplitude (tall RaVR), large R-wave/S-wave ratio (large R/S) in lead aVR, and deep S waves in lead I (deep S in I), correlate with severe TCA poisoning outcomes. This study investigated the occurrence of these characteristic ECG findings in relation to clinical courses in patients with quetiapine poisoning.Methods This single-center, retrospective cohort study analyzed adult patients with quetiapine poisoning. Major complications associated with quetiapine poisoning were defined as a composite of prolonged ICU stays (≥48 h), use of vasopressor, mechanical ventilation, or seizure.Results Among the 76 patients with quetiapine poisoning, 17 had major complications. A prolonged QRS interval, tall RaVR, large R/S, and deep S in I were more frequent in cases with major quetiapine poisoning complications.Discussion Our findings reveal that severe quetiapine poisoning causes ECG findings similar to those of TCA poisoning.Conclusion Further studies are warranted to confirm the association between TCA-like ECG findings and severe quetiapine poisoning.