Dig and EKG

Q: 57 years old male is admitted to ICU with syncope. Further workup led to the diagnosis of Digitalis overdose. PR interval on EKG is expected to be? - select one

A) prolonged

B) shortened

Answer: A

Digitalis overdose can affect the EKG in various ways. Most common are:

• Depression of the J point
• Depression or sagging of the ST segment, concave in an upward direction
• Flattened T waves 
• Shortened QT interval
• PR interval slightly prolonged due to enhanced vagal effect on the atrioventricular node
• Prominent or inverted U waves - This can be a direct digitalis itself, or can be secondary to hypokalemia

#cardiology

#pharmacology

References:

1. Djohan AH, Sia CH, Singh D, Lin W, Kong WK, Poh KK. A myriad of electrocardiographic findings associated with digoxin use. Singapore Med J. 2020 Jan;61(1):9-14. doi: 10.11622/smedj.2020005. PMID: 32043160; PMCID: PMC7900815.

2. Muñoz NL, Buendía AB, Manterola FA. Electrocardiographic Changes After Suicidal Digoxin Intoxication in a Healthy Woman. Open Cardiovasc Med J. 2017 May 16;11:58-60. doi: 10.2174/1874192401711010058. PMID: 28572865; PMCID: PMC5447925.