Introduction: Quetiapine shares sodium channel-blocking properties with tricyclic antidepressants. We present the electrographic findings in two patients with severe quetiapine poisoning.
Case summaries: Two patients poisoned with quetiapine presented with impaired consciousness, requiring mechanical ventilation and vasopressor support, with one also experiencing status epilepticus. Their peak serum quetiapine concentrations were 4.52 mg/L and 25.6 mg/L.
Images: On admission, electrocardiograms for both patients revealed a tall R wave in lead aVR, deep S wave in lead I, and QRS complex duration of 120 ms. These findings gradually resolved in parallel with the improvement in their symptoms.
Conclusion: Severe quetiapine poisoning may cause electrographic changes. Further studies are needed to determine the utility of these electrocardiogram findings for predicting the severity of quetiapine poisoning.
Keywords: Deep S wave in lead I; electrocardiogram; quetiapine poisoning; serum concentration; tall R wave in lead aVR.