Cardiovascular System Exam

Correct Answer: A

Rationale: Excitability is the correct term that describes the ability of cardiac cells to respond to an impulse by contracting. Excitability refers to the cell's ability to respond to stimuli and generate an action potential. Choice B, Contractility, is incorrect as it refers to the ability of cardiac cells to contract after receiving a stimulus, not the response to the impulse itself. Choice C, Rhythmicity, is incorrect as it pertains to the heart's ability to contract rhythmically without external stimulation. Choice D, Conductivity, is incorrect as it refers to the ability of cardiac cells to transmit an impulse from cell to cell, not the direct response to the impulse by contracting.

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.

Correct Answer: A

Rationale: The correct answer is A, Angina. Angina is chest pain or discomfort caused by reduced blood flow to the heart muscle, often due to coronary artery disease. Choice B, Myocardial infarction, involves the death of heart muscle tissue due to a lack of blood supply, presenting with symptoms similar to angina but more severe. Pericarditis (Choice C) is inflammation of the pericardium, the sac surrounding the heart, which may cause chest pain but is not primarily due to reduced blood flow. Arrhythmia (Choice D) refers to abnormal heart rhythms but is not directly related to chest pain due to reduced blood flow.

Correct Answer: A

Rationale: In this scenario, the nurse's priority action should be to hold the digoxin and notify the healthcare provider. A heart rate of 48 bpm is low, and digoxin, being a medication that can further decrease the heart rate, should be withheld. Administering the digoxin as ordered (Choice B) would not be appropriate in this situation as it can exacerbate bradycardia. Atropine (Choice C) is not the initial treatment for this scenario; holding the digoxin is the first action. Increasing the dose of digoxin (Choice D) would be contraindicated due to the client's bradycardia. Therefore, the correct action is to hold the digoxin and inform the healthcare provider for further guidance.

Correct Answer: A

Rationale: The correct action for the nurse to take when a client on a beta blocker presents with a blood pressure of 88/58 mm Hg is to hold the beta blocker and notify the healthcare provider. Beta blockers can further decrease blood pressure, which is already low in this case. Administering the beta blocker as ordered (Choice B) would exacerbate the hypotension. Increasing the dose of the beta blocker (Choice C) would be inappropriate and unsafe given the low blood pressure. Continuing to monitor the client and reassessing in 30 minutes (Choice D) could lead to a delay in necessary intervention. Therefore, the priority is to hold the medication and seek guidance from the healthcare provider.