ATI RN
Cardiovascular System Practice Exam
1. The client on digoxin has a potassium level of 2.7 mEq/L. What is the nurse’s priority action?
- A. Hold the digoxin and notify the healthcare provider.
- B. Administer the digoxin as ordered.
- C. Increase the dose of digoxin.
- D. Administer potassium supplements.
Correct answer: A
Rationale: The correct answer is to hold the digoxin and notify the healthcare provider. A potassium level of 2.7 mEq/L is considered low and can increase the risk of digoxin toxicity. Holding the medication and informing the healthcare provider is crucial to prevent adverse effects. Administering the digoxin as ordered (Choice B) would put the client at a higher risk for toxicity. Increasing the dose of digoxin (Choice C) is not appropriate when the client's potassium level is low. Administering potassium supplements (Choice D) may be necessary but is not the priority action in this situation.
2. What is the term for the amount of blood ejected by the left ventricle into the aorta per beat, determined by preload, contractility, and afterload?
- A. Stroke volume
- B. Cardiac output
- C. End-diastolic volume
- D. Ejection fraction
Correct answer: A
Rationale: The correct answer is A: Stroke volume. Stroke volume refers to the volume of blood ejected by the left ventricle during each heartbeat. This is determined by preload (the degree of stretch of the cardiac muscle fibers at the end of diastole), contractility (the force of myocardial contraction), and afterload (the pressure or resistance that the ventricle must overcome to eject blood). Choice B, Cardiac output, is the volume of blood pumped by the heart per minute and is calculated by multiplying the heart rate by the stroke volume. Choice C, End-diastolic volume, is the volume of blood in the ventricle at the end of diastole before contraction. Choice D, Ejection fraction, is the proportion of blood pumped out of the ventricle with each contraction, calculated by dividing the stroke volume by the end-diastolic volume.
3. What is the term that describes the inability of cardiac cells to respond to a new stimulus while they are still in contraction from a previous stimulus?
- A. Refractoriness
- B. Excitability
- C. Contractility
- D. Automaticity
Correct answer: A
Rationale: Refractoriness is the correct term to describe the inability of cardiac cells to respond to a new stimulus while they are still in contraction from a previous stimulus. This period is essential for the heart to complete its contraction and relaxation phases without interference. Excitability refers to the ability of cells to respond to stimuli, not the inability to respond. Contractility is the force of cardiac muscle contraction, and automaticity is the ability of cardiac cells to generate electrical impulses spontaneously, which are not relevant to the described scenario.
4. What is a condition where the right side of the heart fails due to increased pressure in the pulmonary arteries, often caused by chronic lung disease?
- A. Cor pulmonale
- B. Heart failure
- C. Pulmonary embolism
- D. Myocarditis
Correct answer: A
Rationale: Cor pulmonale is the correct answer. It is a condition where the right side of the heart fails due to increased pressure in the pulmonary arteries, often caused by chronic lung disease such as COPD. Pulmonary embolism (choice C) is a blockage in one of the pulmonary arteries in your lungs. Myocarditis (choice D) is inflammation of the heart muscle. While heart failure (choice B) is a broad term that can involve the failure of either the right or left side of the heart.
5. What term refers to the degree of myocardial fiber stretch before contraction, related to the volume of blood distending the ventricles at the end of diastole, and determined by the amount of venous return?
- A. Preload
- B. Afterload
- C. Contractility
- D. Ejection fraction
Correct answer: A
Rationale: The correct answer is A: Preload. Preload is the degree of myocardial fiber stretch before contraction, influenced by the volume of blood returning to the heart. This parameter is related to the amount of blood in the ventricles at the end of diastole. Choice B, Afterload, refers to the pressure or resistance that the ventricles must overcome to eject blood. Choice C, Contractility, is the intrinsic ability of the heart muscle to contract. Choice D, Ejection fraction, is the percentage of blood pumped out of the ventricles with each contraction.
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