Beta-blocker overdose in a child is likely to cause which cardiac effect?

Beta-blocker overdose in a child is likely to cause which cardiac effect?

• A. Tachycardia
• B. Bradycardia
• C. Hypertension
• D. Ventricular fibrillation

Answer: (B)

Beta-adrenergic blockade in the heart primarily slows the heart rate and slows the conduction through the AV node. When a beta-blocker overdoses, the blockade of beta-1 receptors in the SA node and conduction system becomes exaggerated, reducing automaticity and slowing AV nodal conduction. The result is a pronounced bradycardia, with possible decreased contractility and lower blood pressure if the output drops enough. This is the most expected cardiac effect in a child with beta-blocker overdose. Tachycardia would require sympathetic stimulation or anticholinergic effects, which isn’t typical here; hypertension would usually not be driven by beta-blockade, and ventricular fibrillation, while dangerous, is not the typical early or common manifestation of overdose.

Beta-adrenergic blockade in the heart primarily slows the heart rate and slows the conduction through the AV node. When a beta-blocker overdoses, the blockade of beta-1 receptors in the SA node and conduction system becomes exaggerated, reducing automaticity and slowing AV nodal conduction. The result is a pronounced bradycardia, with possible decreased contractility and lower blood pressure if the output drops enough. This is the most expected cardiac effect in a child with beta-blocker overdose. Tachycardia would require sympathetic stimulation or anticholinergic effects, which isn’t typical here; hypertension would usually not be driven by beta-blockade, and ventricular fibrillation, while dangerous, is not the typical early or common manifestation of overdose.