Nursing Elites

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. 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.

3. This test measures the amount of blood the heart pumps with each beat, often used to assess heart function.

• A. Ejection fraction
• B. Cardiac output
• C. Stroke volume
• D. End-diastolic volume

Correct answer: A

Rationale: The correct answer is A: Ejection fraction. Ejection fraction is a measure of the percentage of blood that is pumped out of the left ventricle with each beat, used to assess heart function. Choice B, Cardiac output, is the total volume of blood pumped by the heart per minute and is not specific to each beat. Choice C, Stroke volume, is the amount of blood ejected by the heart in one contraction but does not specify the percentage of blood pumped out. Choice D, End-diastolic volume, is the volume of blood in the ventricle just before it contracts and does not directly measure the blood pumped with each beat.

4. What is a condition characterized by episodes of severe, acute shortness of breath, often occurring at night?

• A. Paroxysmal nocturnal dyspnea
• B. Sleep apnea
• C. Orthopnea
• D. Dyspnea

Correct answer: A

Rationale: Paroxysmal nocturnal dyspnea is the correct answer. It is characterized by sudden episodes of severe shortness of breath during sleep, often waking the individual. Choice B, Sleep apnea, involves pauses in breathing during sleep but does not usually present with acute shortness of breath. Choice C, Orthopnea, refers to shortness of breath that occurs when lying flat and is relieved by sitting up. Choice D, Dyspnea, is a general term for difficult or labored breathing and does not specifically describe acute episodes at night.

5. What is the condition where the heart's mitral valve does not close properly, allowing blood to leak backward into the left atrium?

• A. Mitral regurgitation
• B. Aortic stenosis
• C. Tricuspid regurgitation
• D. Pulmonary hypertension

Correct answer: A

Rationale: Mitral regurgitation is the condition where the heart's mitral valve does not close properly, allowing blood to leak backward into the left atrium. This can result in symptoms like shortness of breath and fatigue. Choices B, C, and D are incorrect because aortic stenosis, tricuspid regurgitation, and pulmonary hypertension involve different heart valves or conditions, not the mitral valve specifically.

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