Correct Answer: A

Rationale: Ventricular tachycardia is the correct answer. It is a condition characterized by the heart's electrical system malfunctioning, leading to very fast heartbeats originating from the ventricles. Ventricular tachycardia can be life-threatening as it may progress to ventricular fibrillation, causing cardiac arrest. Atrial fibrillation (choice B) involves rapid, irregular beating of the atria, not the ventricles. Supraventricular tachycardia (choice C) originates above the ventricles and does not involve ventricular malfunction. Bradycardia (choice D) is the opposite of tachycardia, characterized by an abnormally slow heart rate.

Correct Answer: B

Rationale: The correct answer is B: Atrioventricular Valves. The atrioventricular (AV) valves, including the mitral valve and tricuspid valve, close during ventricular systole to prevent backflow of blood from the ventricles into the atria. They open during ventricular diastole to allow blood flow from the atria into the ventricles. Semilunar valves, choice A, are located at the exits of the ventricles and prevent backflow into the ventricles. The mitral valve and tricuspid valve, choices C and D, are specific types of AV valves.

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.

Correct Answer: A

Rationale: The correct answer is A: Platelet count. When administering enoxaparin (Lovenox) for DVT prophylaxis, it is crucial to monitor the platelet count as enoxaparin can lead to thrombocytopenia, a decrease in platelet levels. Monitoring the platelet count helps in early detection of this potential adverse effect. Choices B, C, and D are incorrect because PT/INR, aPTT, and hemoglobin levels are not the most important lab values to monitor specifically for enoxaparin administration and DVT prophylaxis.

Correct Answer: A

Rationale: Thoracentesis is the correct answer. It is a procedure where a needle is inserted into the pleural space to drain fluid, relieving pressure and helping the patient breathe more easily. Bronchoscopy (choice B) is a procedure used to examine the airways, not to drain fluid. An echocardiogram (choice C) is an imaging test to assess the heart's structure and function, not related to draining pleural fluid. A CT scan (choice D) is a cross-sectional imaging test that provides detailed pictures of the inside of the body, not used for draining pleural fluid.