Which EKG finding is associated with lithium use?

• A. Inverted T-waves
• B. Prolonged PR interval
• C. ST segment elevation
• D. U waves

Answer: (A)

Lithium can alter the heart’s electrical repolarization, and inverted T waves are a recognized ECG finding in patients on lithium. This pattern reflects changes in ventricular repolarization rather than conduction delay or acute ischemia. The other patterns describe ECG changes more typical of different issues: a prolonged PR interval signals slowed AV conduction from medications or conduction system disease; ST segment elevation points to acute myocardial injury; and U waves are commonly linked to electrolyte disturbances like hypokalemia, not specifically lithium. If a patient on lithium shows T-wave inversions, evaluate electrolytes and renal/thyroid function and monitor for potential toxicity, keeping in mind that isolated inverted T waves can occur with lithium use.