What effect can gingival retraction cord soaked in epinephrine have on a patient?

When gingival retraction cord is soaked in epinephrine, it can lead to an increase in heart rate, a condition known as tachycardia. This is due to the physiological effects of epinephrine, which is a vasopressor and sympathomimetic agent. It stimulates the heart, increases cardiac output, and prepares the body for a 'fight or flight' response.

In a dental setting, using retraction cord with epinephrine helps to temporarily constrict blood vessels in the gingival tissue, reducing bleeding and providing better visibility for the dentist. However, this vasoconstrictive action of epinephrine can also increase heart rate, which is an essential consideration for dental professionals, especially when treating patients with cardiovascular issues.

While bradycardia, immune response, and a decrease in blood pressure are potential reactions to other medications or conditions, they are not effects typically associated with the use of epinephrine. Therefore, tachycardia is the correct choice, as it is a direct consequence of epinephrine's action on the cardiovascular system.