A nurse is reviewing laboratory results for a client who has atrial fibrillation. Which of the following blood test results should the nurse understand can be a possible cause of atrial fibrillation?

A. Atrial fibrillation: Atrial fibrillation is characterized by an irregularly irregular rhythm, absence of identifiable P waves, and irregular ventricular response. The heart rate in atrial fibrillation can be variable, and the absence of identifiable P waves indicates disorganized atrial electrical activity.

B. Sinus bradycardia: Sinus bradycardia is characterized by a regular rhythm with a heart rate less than 60 beats per minute (bpm) and normal P waves preceding each QRS complex. In sinus bradycardia, the PR interval and QRS duration are typically within normal limits.

C. Supraventricular tachycardia: Supraventricular tachycardia (SVT) is characterized by a regular rhythm with a heart rate greater than 100 bpm. SVT typically presents with narrow QRS complexes and may or may not have discernible P waves.

D. First-degree heart block: First-degree heart block is characterized by a prolonged PR interval (>0.20 seconds) but maintains a regular rhythm with normal QRS duration. In first-degree heart block, P waves are typically identifiable, and the rhythm is not irregular.

A. A CT angiogram will reveal any edema within the brain tissue: CT angiography primarily focuses on visualizing blood vessels and blood flow within the brain. While it may incidentally detect areas of edema, its primary purpose is to assess vascular structures rather than brain tissue changes such as edema.

B. A CT angiogram will reveal any overproduction of cerebrospinal fluid (CSF): CT angiography does not assess cerebrospinal fluid (CSF) production. Its main function is to visualize blood vessels and blood flow within the brain, particularly to detect abnormalities such as aneurysms, arteriovenous malformations, or vasospasm.

C. A CT angiogram will reveal any fractures within the skull or spine: CT angiography primarily focuses on imaging blood vessels and is not the preferred modality for detecting fractures within the skull or spine. CT scans or plain radiography are typically used to assess bony structures for fractures.

D. A CT angiogram will reveal any decreased blood flow related to vasospasm: This statement is correct. CT angiography is a specialized imaging technique that combines computed tomography (CT) scanning with contrast dye to visualize blood vessels and blood flow within the brain. It is commonly used to detect and monitor vasospasm, a potentially serious complication of subarachnoid hemorrhage, where blood vessels in the brain constrict, leading to decreased blood flow. CT angiography allows for the visualization of these changes in blood vessel diameter and blood flow dynamics.