23-51: Digoxin Effect, Toxicity

ECG Findings

• ST segment shortening and depression leading to a “scooped” appearance.

• QT interval shortening.

• PR interval prolongation.

• Decreased T-wave amplitude.

• Premature ventricular complexes are the most common dysrhythmia.

• Bradydysrhythmias, heart block, especially with findings consistent with increased automaticity (atrial tachycardia with block, atrial fibrillation with slow ventricular response, accelerated junctional rhythms).

• Bidirectional VT may rarely be seen (see Fig. 17.99).

Pearls

1. ECG changes associated with digoxin can be seen from therapeutic or toxic levels.

2. ST-segment changes may be exaggerated by myocardial disease or tachycardia.

3. An acute overdose of a digoxin is usually associated with hyperkalemia, which may increase the height of the T wave.

4. Avoid calcium for treatment of hyperkalemia in the setting of digoxin toxicity as this may potentiate adverse effects of digoxin.