Effects of Medication and Pathophysiology on 12-lead Electrocardiograms in Bipolar Disorder and Schizophrenia

Background: Cardiovascular disease is the principal cause of death among patients with bipolar disorder and schizophrenia. We hypothesized that a combination of psychophysiology and the use of lithium, along with antipsychotics, alter electrocardiophysiological activity in bipolar and schizophrenic patients. Purpose: The goal of this study was to evaluate the effects of psychotropic agents and the pathophysiology using 12-lead electrocardiograms (EKGs) in bipolar and schizophrenic patients. Methods: The study involved three groups of patients: (1) 30 lithium/haloperidol-treated patients with bipolar mania (15 males, 15 females); (2) 33 lithium-free patients with bipolar mania (21 males, 12 females); and (3) 31 lithium-free schizophrenic patients (15 males, 16 females). Clinical data were obtained through a retrospective review of the medical records of all subjects. Results: The mean PQ interval, QRS complex, and corrected QT (QTc) intervals did not differ among the three groups. Among those in the lithium/haloperidol-treated bipolar mania group, the QTc interval demonstrated a marginally significant correlation with serum lithium levels (r = 0.373; p = 0.05). Conclusion: Pathophysiological changes or minor abnormalities of electrocardiophysiological activity in schizophrenia and bipolar disorder patients might not be displayed by routine 12-lead EKGs. Because of the limitations of 12-lead EKGs, bipolar manic patients who have higher serum lithium levels might have increased risks for QTc prolongation, and thus QTc intervals should be carefully followed-up in these patients.