From the Guidelines
The ST segment changes that could be read as a digitalis (digoxin) effect are a sagging or scooped ST segment, often described as a "scoop" or "soup ladle" shape.
Digitalis Effect on ECG
- The digitalis effect is typically seen with prolonged use of digitalis [ 1 ]
- This effect is a result of the drug's impact on cardiac repolarization, leading to characteristic changes in the ST segment
- The "scoop" or "soup ladle" ST segment is a classic description of the digitalis effect, which occurs independently of QRS depolarization changes [ 1 ]
- It is essential to consider electrolyte abnormalities, such as serum calcium and potassium levels, when interpreting ECG changes, as they can also affect repolarization [ 1 ]
From the FDA Drug Label
The use of therapeutic doses of digoxin may cause prolongation of the PR interval and depression of the ST segment on the electrocardiogram. Digoxin may produce false positive ST-T changes on the electrocardiogram during exercise testing. Digoxin produces PR prolongation and ST segment depression which should not by themselves be considered digoxin toxicity.
The ST segment changes that could be read as a digitalis (digoxin) effect are ST segment depression. 2 2
From the Research
ST Segment Changes Associated with Digitalis Effect
The ST segment changes that could be read as a digitalis (digoxin) effect include:
- Depression of the ST segment, which can be dose-dependent and may be associated with therapeutic digitalis levels 3, 4
- A linearly intensifying depression of the ST segment with increasing digitalis dosage 4
- Severe ST-segment depression with a J point of greater than or equal to 100 microV, which can be a strong indicator of higher serum digoxin concentrations 3
- Upsloping ST segment, which can be distinguished from the ST segment changes associated with hypokalemia 5
Key Characteristics of Digitalis-Induced ST Segment Changes
The digitalis-induced ST segment changes can be characterized by:
- A trend toward progressive depression of the ST segment with increasing serum digoxin concentrations 3
- A decrease in T-wave amplitude, which can be associated with digitalis effect 3, 6
- The presence of a normal ST segment in four leads (I, aVF, V5, V6) can exclude the presence of a serum digoxin concentration greater than 1.3 ng/ml 3