CAMRT Radiography Practice Exam

When are beta-blockers typically used in cardiac CT protocols?

1. When the patient's heart rate exceeds 65 bpm

2. When the patient exhibits symptoms of asthma

3. When there is a history of iodine allergy

4. When the patient is very active

The correct answer is: When the patient's heart rate exceeds 65 bpm

Beta-blockers are commonly used in cardiac CT protocols to manage heart rate during imaging procedures. The primary objective is to achieve a target heart rate, usually below 65 beats per minute, to enhance image quality and reduce motion artifacts. A slower heart rate allows for clearer images of the coronary arteries, making it easier to detect any potential abnormalities. In the context of cardiac assessments, a heart rate exceeding 65 bpm can hinder the resolution and clarity of the images captured, making it crucial to administer beta-blockers if the heart rate is high. They work by blocking the effects of adrenaline on the heart, leading to a decrease in heart rate and, therefore, improved imaging outcomes during a CT scan. Other options, while relevant to patient management in various contexts, do not align with the clinical rationale behind the use of beta-blockers specifically in cardiac CT protocols. For instance, managing asthma typically involves bronchodilators rather than beta-blockers, and issues such as iodine allergy pertain more to contrast media administration instead of heart rate management. Additionally, a patient’s level of physical activity could affect heart rate but does not serve as an indication for beta-blocker use prior to a cardiac CT.