Electrocardiography changes in bipolar patients during long-term lithium monotherapy

Area of Science:

• Cardiology
• Psychiatry
• Pharmacology

Background:

• Lithium is a common mood stabilizer for bipolar disorder (BD).
• Cardiovascular side effects of lithium are typically associated with supra-therapeutic serum levels.
• The impact of long-term lithium use within therapeutic ranges on cardiac electrical activity requires further investigation.

Purpose of the Study:

• To assess the long-term effects of lithium monotherapy on electrocardiogram (ECG) parameters in bipolar disorder (BD) patients.
• To compare ECG parameters between BD patients on lithium and healthy controls (HCs).
• To investigate the association between serum lithium levels and ECG parameters.

Main Methods:

• A cohort of 53 euthymic BD type I patients on lithium monotherapy (≥12 months) and 45 HCs were recruited.
• Standard 12-lead surface ECGs were recorded for 5 minutes under resting conditions.
• Key ECG parameters including QT dispersion ratio (QTdR) and Tpeak-to-end interval (TpTe) were measured.

Main Results:

• BD patients on chronic lithium treatment exhibited significantly increased QT dispersion ratio (QTdR), Tpeak-to-end interval (TpTe), Pmax, and Pmin compared to HCs.
• These associations remained significant after controlling for age, sex, and applying Bonferroni correction.
• No correlation was found between serum lithium levels and the measured ECG parameters.

Conclusions:

• Long-term lithium use is associated with atrial and ventricular electrical instability in BD patients.
• These cardiac electrical changes occur even within the therapeutic serum lithium range.
• The findings highlight the importance of cardiac monitoring in patients on long-term lithium therapy.