ATI RN
Cardiovascular System Exam
1. What does the PR interval measure?
- A. Time it takes for the electrical impulse to travel from the atria to the ventricles
- B. Measurement of ventricular depolarization
- C. Duration of ventricular repolarization
- D. Segment representing the time between ventricular depolarization and repolarization
Correct answer: A
Rationale: The PR interval measures the time it takes for the electrical impulse to travel from the atria to the ventricles. It is crucial in diagnosing heart rhythm disorders, as abnormalities in this interval can indicate conduction abnormalities between the atria and ventricles. Choices B, C, and D are incorrect. The QRS complex represents ventricular depolarization, the QT interval represents the duration of ventricular repolarization, and the ST segment represents the time between ventricular depolarization and repolarization.
2. Which heart chamber receives oxygenated blood from the lungs and pumps it to the rest of the body?
- A. Left atrium
- B. Right atrium
- C. Left ventricle
- D. Right ventricle
Correct answer: C
Rationale: The correct answer is the left ventricle. It receives oxygenated blood from the left atrium and pumps it to the rest of the body through the aorta. The left atrium receives oxygenated blood from the lungs, the right atrium receives deoxygenated blood from the body, and the right ventricle pumps deoxygenated blood to the lungs.
3. What structures hold up the AV valves and are anchored to the ventricular wall by the papillary muscles?
- A. Chordae tendineae
- B. Papillary muscles
- C. Semilunar valves
- D. Aortic valve
Correct answer: A
Rationale: The correct answer is A: Chordae tendineae. Chordae tendineae are fibrous cords that connect the AV valves to the papillary muscles, preventing the valves from inverting during ventricular contraction. Papillary muscles (choice B) anchor the chordae tendineae to the ventricular wall but do not hold up the AV valves directly. Semilunar valves (choice C) are located between the ventricles and the major arteries and are not involved in holding up the AV valves. The aortic valve (choice D) is one of the semilunar valves and is not responsible for holding up the AV valves.
4. The client on furosemide (Lasix) has a potassium level of 3.1 mEq/L. What is the nurse’s priority action?
- A. Administer a potassium supplement.
- B. Hold the furosemide and notify the healthcare provider.
- C. Continue the current dose of furosemide.
- D. Administer Digibind.
Correct answer: A
Rationale: The correct answer is to administer a potassium supplement. A potassium level of 3.1 mEq/L indicates hypokalemia, which can lead to serious complications like cardiac dysrhythmias. Therefore, the priority action is to address the low potassium level by administering a potassium supplement. Holding the furosemide (Choice B) may be necessary in the long term to prevent further potassium loss, but the immediate need is to correct the low potassium level. Continuing the current dose of furosemide (Choice C) without addressing the low potassium level can worsen hypokalemia. Administering Digibind (Choice D) is not indicated for low potassium levels; Digibind is used to treat digoxin toxicity.
5. The client is on a calcium channel blocker. What is the expected effect on the heart?
- A. Increased heart rate
- B. Decreased heart rate
- C. Increased blood pressure
- D. Decreased blood pressure
Correct answer: D
Rationale: When a client is on a calcium channel blocker, the expected effect on the heart is a decreased heart rate and decreased blood pressure. Calcium channel blockers work by dilating blood vessels and reducing the heart's workload, resulting in decreased blood pressure. Choice A, increased heart rate, is incorrect as calcium channel blockers actually have a negative chronotropic effect, reducing the heart rate. Choice C, increased blood pressure, is also incorrect because these medications are used to lower blood pressure.
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