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Time sequence of direct vascular and inotropic effects following intravenous administration of digoxin in normal man
International Journal of Clinical Pharmacology and Biopharmacy
|April 1, 1977
Insights
Digoxin bolus injection initially increases systemic vascular resistance. The positive inotropic effects on heart muscle function are delayed, occurring 10–30 minutes post-injection in healthy individuals.
Area of Science:
- Cardiology
- Pharmacology
- Physiology
Background:
- Digoxin is a cardiac glycoside used to treat heart failure and arrhythmias.
- Understanding its hemodynamic effects and onset of action is crucial for clinical application.
Purpose of the Study:
- To investigate the acute hemodynamic and left ventricular functional effects of a digoxin bolus injection.
- To determine the time course of digoxin's inotropic action on the myocardium.
Main Methods:
- Utilized cardiac ultrasound, electrocardiogram (ECG), carotid pulse pressure, and arterial blood pressure monitoring.
- Administered a bolus injection of digoxin to 5 healthy human volunteers.
- Analyzed immediate and delayed physiological responses.
Main Results:
- Observed an immediate increase in systemic vascular resistance post-digoxin injection.
- Demonstrated a delayed onset of inotropic action on the myocardium, ranging from 10 to 30 minutes.
- Cardiac ultrasound and hemodynamic parameters revealed specific changes in ventricular function.
Conclusions:
- The hemodynamic response to digoxin is biphasic, with initial vascular effects preceding myocardial contractility enhancement.
- Clinicians should be aware of the delayed inotropic effect of digoxin when initiating therapy or managing acute conditions.
Abstract:
The effects of a bolus injection of digoxin upon hemodynamics and left ventricular function were studied in 5 normal volunteers using cardiac ultrasound, ECG, carotid pulse pressure, and arterial blood pressure recording. Whereas the injection was followed by an immediate rise of the systemic vascular resistance, the inotropic action upon the myocardium followed with a delay of 10 to 30 minutes after injection.