Bipolar Research Today is a free monthly online journal that collates and summarizes the latest research about Bipolar, including details on bipolar disorder, symptoms, treatment, depression, medication.

Unmasking of brugada syndrome by lithium.

Darbar D, Yang T, Churchwell K, Wilde AA, Roden DM

Division of Clinical Pharmacology, Vanderbilt University School of Medicine, Nashville, TN 37232-6602, USA. dawood.darbar@vanderbilt.edu

BACKGROUND: The characteristic ECG pattern of ST-segment elevation in V1 and V2 in the Brugada syndrome is dynamic; it is often intermittently present in affected individuals and can be unmasked by sodium channel blockers, including antiarrhythmic drugs and tricyclic antidepressants. We report here 2 patients who developed the Brugada ECG pattern after administration of lithium, a commonly used drug not previously reported to block cardiac sodium channels. METHODS AND RESULTS: Lithium induced transient ST-segment elevation (type 1 Brugada pattern) in right precordial leads at therapeutic concentrations in 2 patients with bipolar disorder. Lithium withdrawal in the patients resulted in reversion to type 2 or 3 Brugada patterns or resolution of ST-T abnormalities. In Chinese hamster ovary cells transfected with SCN5A, which encodes the cardiac sodium channel, lithium chloride caused concentration-dependent block of peak INa at levels well below the therapeutic range (IC50 of 6.8+/-0.4 micromol/L). CONCLUSIONS: The widely used drug lithium is a potent blocker of cardiac sodium channels and may unmask patients with the Brugada syndrome.

Published 13 September 2005 in Circulation, 112(11): 1527-31.
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