Digoxin-induced positive exercise tests: their clinical and prognostic significance

Area of Science:

• Cardiology
• Exercise Physiology

Background:

• Digoxin is commonly prescribed, and its effect on exercise testing is not fully understood.
• Exercise stress tests are crucial for diagnosing coronary artery disease.

Purpose of the Study:

• To assess how digoxin impacts exercise test outcomes.
• To determine the prognostic value of digoxin-induced positive exercise tests.
• To explore the relationship between age and digoxin's effect on exercise tests.

Main Methods:

• 98 healthy men underwent daily exercise tests after 14 days of digoxin (0.25 mg/day) until a negative response.
• Follow-up included medical history and repeat exercise tests after 5 years.
• Logistic regression analysis was used to estimate the probability of digoxin-induced positive tests.

Main Results:

• 25% of subjects (22/98) exhibited digoxin-induced positive exercise tests.
• Positive test incidence increased with age, reaching 100% in men over 60.
• No significant S-T depression persisted beyond 6 minutes post-exercise, and tests normalized 12 days after digoxin withdrawal.

Conclusions:

• Exercise testing can provide valuable information in patients taking digoxin.
• The probability of a positive test being digoxin-induced can be estimated.
• Digoxin withdrawal for 12 days is necessary to eliminate its electrocardiographic effects.
• Digoxin may reveal underlying coronary artery disease.