Sympathetic activation is an example of which chronotropic effect on heart rate?

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Prepare for the Cardiac Electrophysiology Test. Study with flashcards and multiple choice questions, each question includes hints and explanations. Enhance your expertise and get ready for your certification!

Multiple Choice

Sympathetic activation is an example of which chronotropic effect on heart rate?

Explanation:
Sympathetic activation increases heart rate, which is a positive chronotropic effect. Norepinephrine released onto beta-1 receptors in the SA node raises cAMP, activating PKA. This enhances the funny current (I_f) and L-type calcium current, making the diastolic depolarization steeper and speeding up SA nodal firing (and AV nodal conduction). The result is a faster heart rate. The term “inotropic chronotropic” isn’t appropriate here, since inotropic refers to contractility, not rate.

Sympathetic activation increases heart rate, which is a positive chronotropic effect. Norepinephrine released onto beta-1 receptors in the SA node raises cAMP, activating PKA. This enhances the funny current (I_f) and L-type calcium current, making the diastolic depolarization steeper and speeding up SA nodal firing (and AV nodal conduction). The result is a faster heart rate. The term “inotropic chronotropic” isn’t appropriate here, since inotropic refers to contractility, not rate.

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