29 Questions
What is the approximate 5-year mortality rate for heart failure?
50%
What is the most common cause of heart failure in the USA?
Coronary artery disease
In systolic failure, what is typically reduced?
Ejection fraction
Which type of heart failure is more common in older patients?
Diastolic failure
What is a characteristic of diastolic failure?
Stiffening and loss of adequate relaxation
What is the trend in the prevalence of heart failure?
Increasing
What are the two primary goals of treatment in heart failure?
Reducing symptoms and slowing progression
What is the name of the plant family that provides medically useful cardiac glycosides?
Digitalis
What is the extent of absorption of digoxin after oral administration?
65–80%
Where are cardiac glycosides distributed in the body?
Widely distributed to tissues, including the CNS
How is digoxin primarily eliminated from the body?
Excreted unchanged by the kidneys
What is the relationship between digoxin's renal clearance and creatinine clearance?
Directly proportional
What is the primary mechanism by which cardiac glycosides increase cardiac contractility?
Inhibition of Na+/K+-ATPase, leading to increased intracellular sodium concentration
What is the result of the inhibition of Na+/K+-ATPase by cardiac glycosides?
An increase in intracellular sodium concentration
What is the role of the sodium-calcium exchanger in the mechanism of cardiac glycosides?
It reduces calcium expulsion from the cell
What is the effect of cardiac glycosides on the electrical properties of the heart?
A mixture of direct and autonomic actions
What is the mechanism by which cardiac glycosides increase the free calcium concentration in the vicinity of the contractile proteins?
A two-step process involving Na+/K+-ATPase inhibition and the sodium-calcium exchanger
What is the therapeutic effect of cardiac glycosides?
Positive inotropy
What is the primary effect of cardiac glycosides on the cardiac action potential?
Early and brief prolongation of the action potential
What is the main mechanism by which cardiac glycosides slow AV conduction?
Increasing vagal outflow
What is the consequence of an excessively rapid ventricular rate?
Inadequate time for diastolic filling
What is the effect of larger doses of glycosides on sinus rhythm?
Disturbance of sinus rhythm
What is the result of inhibition of the Na+/K+ pump by glycosides?
Depolarization
What is the potential consequence of slowing AV conduction by cardiac glycosides?
AV block
What is the consequence of increased [Ca2+]i in the cardiac muscle?
Coupled beats followed by ventricular tachycardia and eventually ventricular fibrillation
What is the primary site of digitalis toxicity outside the heart?
Gastrointestinal tract
What is the cause of gastrointestinal toxicity associated with digitalis?
Both direct effects on the gastrointestinal tract and CNS actions
What is a rare effect of digitalis in men?
Gynecomastia
What is a possible CNS effect of digitalis?
Aberrations of color perception
Heart failure is a serious condition that occurs when the heart cannot provide enough oxygen to the body. Learn about the common causes, such as coronary artery disease and hypertension, and the two main types of heart failure. Test your knowledge on this critical topic.
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