What effect does digitalis have on the EKG?

What effect does digitalis have on the EKG?

• A. Gradual upward curve of ST segment
• B. Gradual downward curve of the ST segment
• C. Flattening of all waves
• D. Widening of the QRS complex

Answer: (B)

Digitalis, a cardiac glycoside, has specific effects on the heart's electrical conduction system, which can be observed on the EKG. The correct choice indicates a gradual downward curve of the ST segment, known as "digoxin effect". This downward trend is commonly associated with digitalis therapy.

When digitalis is administered, it increases intracellular calcium levels, which enhances the contractility of the heart. However, as it affects the repolarization processes, particularly through its influence on potassium and calcium channels, the ST segment becomes altered. Instead of remaining flat after the QRS complex, the ST segment appears to curve downward, reflecting the altered repolarization phase.

This characteristic change is significant in diagnosing digitalis toxicity and differentiating it from other conditions that may also affect the EKG but do not produce the same downward curvature in the ST segment. Understanding this effect is essential for medical professionals managing patients on digitalis therapy, as it can inform decisions around patient care and medication management.