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[Behaviour of the ST segment under stress by atrial frequency and digitalis in latent coronary insufficiency
Insights
Therapeutic digitalis doses can cause ST segment depression in ECGs, potentially indicating myocardial ischemia. This effect is dose-dependent and regularly observed in patients, even at lower digoxin levels.
Area of Science:
- Cardiology
- Clinical Electrophysiology
- Pharmacology
Context:
- Digitalis glycosides are commonly prescribed for heart conditions.
- ST segment changes in ECGs can signify cardiac ischemia.
- The impact of digitalis on ECGs, particularly ST segments, requires clarification.
Purpose:
- To investigate the effect of therapeutic digitalis doses on ST segment behavior.
- To determine if digitalis-induced ST depression correlates with myocardial ischemia.
- To establish the dose-dependency of these ECG changes.
Summary:
- Therapeutic digitalis administration was studied in 7 patients using ECGs at rest and during induced atrial pacing.
- A consistent, dose-dependent ST segment depression was observed, linearly intensifying with increasing digitalis dosage.
- This effect was detectable even at an average effective digoxin level of 0.59 mg.
Impact:
- Glycoside-induced ST depressions are not benign and may reflect underlying myocardial ischemia.
- This finding necessitates careful interpretation of ECGs in patients on digitalis therapy.
- Highlights the importance of considering drug effects when assessing cardiac ischemia.
Abstract:
Therapeutic doses of digitalis may give rise to depressions and abnormities of the ST segment. In coronary patients this is occasionally also associated with anginal complaints. In 7 patients the ST segment was investigated at rest and under increasing stress by atrial frequency without and with digitalis at increasing therapeutic dosage. In all patients a glycoside-induced, linearly intensifying depression of the ST segment was demonstrated as a regular and dose-dependent pattern the onset of which was already recognizable at an average effective level of 0,59 mg digoxin. The opinion is held that glycoside-induced ST depressions in the ECG are not in general of insignificant nature but may be the reflection of myocardial ischemia.