Sinus Node Dysfunction After Acute Lithium Treatment at Therapeutic Levels.

Area of Science:

• Cardiology
• Psychiatry
• Pharmacology

Background:

• Lithium carbonate is a widely used psychiatric medication.
• It has a narrow therapeutic window, necessitating close serum concentration monitoring.
• Cardiac toxicity, including arrhythmias, can occur even at therapeutic lithium levels.

Purpose of the Study:

• To report a case of asymptomatic severe bradycardia in a psychiatric inpatient due to lithium treatment.
• To investigate the relationship between lithium toxicity and sinus node dysfunction.
• To highlight the importance of regular cardiac monitoring during lithium therapy.

Main Methods:

• Case report of a psychiatric inpatient.
• Serial electrocardiograms and Holter monitoring.
• Assessment of serum lithium levels and thyroid function.

Main Results:

• The patient developed asymptomatic severe bradycardia, likely due to sinus node dysfunction, during acute lithium treatment at therapeutic levels.
• Bradycardia improved after lithium withdrawal, confirmed by serial ECGs and Holter monitoring.
• Baseline sinus bradycardia and borderline thyroid function may have been contributing factors.

Conclusions:

• Lithium toxicity can manifest as severe bradycardia and sinus node dysfunction, even at therapeutic serum levels.
• Regular electrocardiogram and serum lithium level monitoring are essential for safe lithium prescribing.
• Clinicians should be vigilant for cardiac complications in patients treated with lithium.