A client who has a history of a major myocardial infarction is taking

A client who has a history of a major myocardial infarction is taking digoxin. The nurse explains this medication helps increase cardiac output by:

1. Increasing the heart rate
2. Reducing the resistance of pulmonary circulation
3. Increasing the force of the myocardial contraction
4. Increasing cardiac conduction

ANSWER

ANS: 3
Myocardial contractility affects stroke volume and cardiac output. Increased contraction increas-es the amount of blood ejected by the ventricles. Digoxin increases cardiac output by inhibiting the sodium-potassium ATPase, which makes more calcium available for contractile proteins, which results in a positive inotropic effect. One of the adverse reactions of digoxin is bradycar-dia. Digoxin does not reduce the resistance of pulmonary circulation or affect the electrical con-duction of the heart.