Why does digoxin cause ST segment depression?
Mechanism. The ECG features of digoxin effect are seen with therapeutic doses of digoxin and are due to: Shortening of the atrial and ventricular refractory periods — producing a short QT interval with secondary repolarisation abnormalities affecting the ST segments, T waves and U waves.
Does digoxin cause ST depression?
Digoxin can cause many different ECG abnormalities when supratherapeutic levels occur. The classic digoxin effect appears as a downsloping ST segment depression, also known as the “reverse tick” or “reverse check” sign.
How does digoxin work in terms of altering movement of Na+ K+ and Ca ++ and how does that relate to the improvement in cardiac function?
Digoxin increases the force of contraction of the muscle of the heart by inhibiting the activity of an enzyme (ATPase) that controls movement of calcium, sodium, and potassium into heart muscle. Calcium controls the force of contraction.
What is downsloping ST depression?
Exercise-induced downsloping ST-segment depression is a common manifestation of severe myocardial ischemia. Although greater downsloping ST-segment depression is suspected to indicate more severe ischemia, its exact relationship to regional myocardial blood flow (RMBF) has not yet been clarified.
What does ST-segment depression indicate?
It is often a sign of myocardial ischemia, of which coronary insufficiency is a major cause. Other ischemic heart diseases causing ST depression include: Subendocardial ischemia or even infarction. Subendocardial means non full thickness ischemia.
Which would be considered a therapeutic effect of digoxin?
Digoxin is used to treat heart failure and abnormal heart rhythms (arrhythmias). It helps the heart work better and it helps control your heart rate.
How does digoxin work with potassium?
Digoxin blocks the sodium/potassium ATPase pump. The mechanism by which this decreases AV conduction is not clear but is perhaps due to increased vagal tone. Intracellular calcium within the cardiac myocytes is increased by digoxin, resulting in increased inotropy, or contractility.
How does digoxin work in atrial fibrillation?
Digoxin is a type of drug called a cardiac glycoside. Their function is to slow your heart rate down and improve the filling of your ventricles (two of the chambers of the heart) with blood. For people with atrial fibrillation, where the heart beats irregularly, a different volume of blood is pumped out each time.