Correct Answer: A

Rationale: The correct answer is A, Arrhythmia. Arrhythmia refers to an irregular heartbeat caused by the malfunction of the heart's electrical system. Bradycardia (choice B) is a condition characterized by a slow heart rate, while Tachycardia (choice C) is a condition characterized by a fast heart rate. Ventricular fibrillation (choice D) is a life-threatening arrhythmia where the heart's lower chambers quiver erratically.

Correct Answer: A

Rationale: Mitral regurgitation is the correct answer. It occurs when the mitral valve does not close properly, allowing blood to flow backward into the left atrium. This condition can lead to symptoms such as fatigue, shortness of breath, and if left untreated, it can progress to heart failure. Aortic stenosis (choice B) is a different heart valve condition characterized by narrowing of the aortic valve, restricting blood flow from the heart. Tricuspid regurgitation (choice C) involves the tricuspid valve not closing properly, leading to blood flowing back into the right atrium. Pulmonary hypertension (choice D) is a condition characterized by high blood pressure in the arteries of the lungs.

Correct Answer: A

Rationale: The correct action for a client on spironolactone with a potassium level of 6.0 mEq/L is to hold the medication and notify the healthcare provider. Spironolactone is a potassium-sparing diuretic that can further elevate potassium levels, which are already high. Administering a potassium supplement (Choice B) would exacerbate the hyperkalemia. Continuing the spironolactone as ordered (Choice C) could lead to worsening hyperkalemia. Increasing the dose of spironolactone (Choice D) would be contraindicated in the presence of elevated potassium levels.

Correct Answer: A

Rationale: The correct answer is Purkinje fibers. Purkinje fibers are specialized conducting fibers that distribute the electrical impulse to the ventricles, leading to their contraction. The SA node (sinoatrial node) is responsible for initiating the electrical impulse in the heart, the AV node (atrioventricular node) delays the impulse to allow for proper atrial contraction before ventricular contraction, and the Bundle of His transmits the impulse from the AV node to the ventricles. Therefore, choices B, C, and D are not the correct options for fibers directly distributing the impulse to the ventricles.

Correct Answer: A

Rationale: The correct answer is A, pulmonary embolism. Pulmonary embolism is a condition where a blood clot blocks one of the pulmonary arteries in the lungs, resulting in symptoms like chest pain, shortness of breath, and other related signs. Choices B, C, and D are incorrect because pneumothorax refers to a collapsed lung, pulmonary edema is the build-up of fluid in the lungs, and pulmonary hypertension is high blood pressure in the arteries of the lungs - none of which directly involve a blood clot blocking the pulmonary arteries.