Which cardiovascular effect is expected after epinephrine 1:1000 administration?

Which cardiovascular effect is expected after epinephrine 1:1000 administration?

• A. Decreased heart rate
• B. Increased heart rate
• C. Decreased contractility
• D. Decreased blood pressure

Answer: (B)

Epinephrine acts on beta-1 receptors in the heart, which increases the rate of firing of the SA node and speeds conduction through the AV node. This produces a positive chronotropic effect, meaning the heart rate goes up. It also boosts contractility (positive inotropy), but the question highlights the most prominent cardiovascular effect after this administration, which is tachycardia from beta-1 stimulation. While epinephrine also raises blood pressure via alpha-adrenergic vasoconstriction and beta-2–mediated effects, the direct, expected outcome on the heart’s rate is an increase. The other options describe effects that epinephrine does not primarily cause at this dose.

Epinephrine acts on beta-1 receptors in the heart, which increases the rate of firing of the SA node and speeds conduction through the AV node. This produces a positive chronotropic effect, meaning the heart rate goes up. It also boosts contractility (positive inotropy), but the question highlights the most prominent cardiovascular effect after this administration, which is tachycardia from beta-1 stimulation. While epinephrine also raises blood pressure via alpha-adrenergic vasoconstriction and beta-2–mediated effects, the direct, expected outcome on the heart’s rate is an increase. The other options describe effects that epinephrine does not primarily cause at this dose.