A 83 year old woman presents with nausea, vomiting, and altered mental status. She is currently oriented x1 and very confused. Her family says that this is not normal for her. You place an IV, place the patient on cardiac monitoring, obtain a blood sugar, and obtain the following ECG below:

What medication is most likely the cause of her symptoms?

1. Azithromycin

2. Haldol

3. Digoxin

4. Metoprolol 

5. Sotalol

Answer D. Digoxin. If you look at the ECG above you can see beat to beat variation in QRS amplitude for leads V1-V3 which is suggestive of bidirectional ventricular tachycardia. Digoxin can cause many different types of dysrhythmias at toxic levels. This is because Digoxin inhibits the Na+/K+ ATP pump and alters the sodium gradient of the Na+/Ca++ exchanger. As a result, it increases levels of intracellular calcium. It also affects AV/SA nodal conduction.  As a result toxic levels of digoxin are associated with varying findings on ECG including: bradycardia, heart block, frequent PVCs, slow atrial fibrillation, ventricular tachycardia and more.  Bidirectional ventricular tachycardia is more specific for digoxin toxicity. Calcium is contraindicated in treatment of digoxin toxicity and can lead to cardiac arrest. The treatment for digoxin toxicity is digoxin-specific antibody fragments.

References:

• Albert, Chonyang & Kamdar, Forum & Hanna, Mazen. (2016). Contemporary Controversies in Digoxin Use in Systolic Heart Failure. Current Heart Failure Reports. 13. 10.1007/s11897-016-0302-z. 

• Mattu A, Tabas JA, Brady WJ. Electrocardiography in Emergency, Acute, and Critical Care. 2e, 2019

• https://litfl.com/bidirectional-ventricular-tachycardia-bvt-ecg-library/