Effects of Lithium Therapy on Ventricular Repolarization in Bipolar Disorder Patients
Cemil Zenci̇r, Kadir Karakuş, Oktay Kocabaş, Gökhan Bahti̇yar, Mithat Selvi̇, Kayıhan Karaman
Keywords: Bipolar disorder, lithium, Tp-e interval, ventricular repolarization
Introduction: Bipolar disorder (BD) is a significant mental health concern in the world. Most of the drugs used in the treatment of bipolar disease may cause life-threatening arrhythmias by affecting the distribution of ventricular repolarization (VR). VR is commonly assessed using QT interval and Twave measurements. The aim of this study was to evaluate VR using the T peak to T end (Tp-e) interval and the Tp-e/QT ratio and to investigate the relationship between lithium therapy and VR parameters in patients with BD. Patients and Methods: Forty-six BD patients under lithium therapy and 45 participants in a control group were included in our study. The Tp-e interval and Tp-e/QT ratio were measured using 12derivation electrocardiography (ECG). These parameters were compared between groups. Results: The QT interval (p= 0.01), QTc interval (p= 0.003), Tp-e interval (p< 0.001), and Tpe/QT ratio (p= 0.009) were significantly higher in patients with BD than in the control group. There was a positive correlation between the Tp-e interval and serum lithium levels (r= 0.317, p< 0.032). In addition, the increased serum lithium level (β= 0.398, p= 0.007) was found to be an independent predictor of the prolonged Tp-e interval. Conclusion: Prolonged Tp-e interval may be a useful indicator of increased risk of ventricular arrhythmia in patients using lithium therapy.