Correct Answer: A

Rationale: The correct answer is the SA node. The sinoatrial (SA) node is known as the natural pacemaker of the heart as it generates electrical impulses initiating each heartbeat. The SA node is located in the right atrium and sets the rhythm and rate of the heartbeat. The AV node (choice B) is responsible for delaying the electrical impulse to allow the atria to contract before the ventricles. Purkinje fibers (choice C) are specialized cardiac fibers responsible for the rapid conduction of impulses to the myocardial cells, and the atria (choice D) are the upper chambers of the heart involved in receiving blood from the veins.

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.

Correct Answer: A

Rationale: Pleural effusion is the correct answer as it refers to the accumulation of excess fluid between the layers of the pleura surrounding the lungs and chest cavity. This condition can be caused by various factors such as infections, heart failure, or cancer. Pulmonary edema (choice B) involves fluid accumulation in the lungs' air sacs and is not specific to the pleura. Atelectasis (choice C) is the collapse or closure of a lung leading to airless lung tissue and is not related to fluid buildup. Sarcoidosis (choice D) is a condition characterized by the growth of tiny collections of inflammatory cells in different parts of the body, not specifically involving fluid accumulation in the pleural space.

Correct Answer: A

Rationale: The correct answer is A, Coronary artery bypass graft (CABG). This surgical procedure involves grafting a blood vessel to bypass a blocked coronary artery, improving blood flow to the heart muscle. Choice B, Valve replacement, is a procedure to replace a damaged heart valve and is not directly related to bypassing blocked arteries. Choice C, Stent placement, involves inserting a mesh tube to keep blocked arteries open and is different from grafting a blood vessel. Choice D, Angioplasty, is a procedure to widen narrowed or blocked arteries, typically using a balloon catheter, and does not involve grafting a blood vessel.

Correct Answer: A

Rationale: When a client on amiodarone develops pulmonary fibrosis, a serious side effect, the immediate action the nurse should take is to notify the healthcare provider. This is crucial because pulmonary fibrosis can lead to severe respiratory compromise and requires prompt evaluation and management by the healthcare provider. Continuing the medication (choice B) can worsen the condition, and delaying action by reducing the dose and monitoring respiratory status (choice D) may not be appropriate given the seriousness of pulmonary fibrosis. Discontinuing the medication and starting oxygen therapy (choice C) may be necessary, but the priority is to notify the healthcare provider first for further assessment and guidance.