HRS Board Review 2025 New Courses (Reviewers Copy)-Workshop 1_Tomaselli_2025

Video Transcription

Video Summary

Adenosine activation of A1 receptors is the correct answer for affecting cardiac electrophysiology, causing a more negative maximal diastolic potential, slowing phase IV diastolic depolarization, and shortening the action potential duration. These effects occur via direct activation of G-protein coupled adenosine receptors and IKACH, leading to potassium channel opening and hyperpolarization. Indirectly, adenosine inhibits adenylyl cyclase, resulting in anti-adrenergic effects and reduced calcium current. Adenosine's impact can be altered by blocking its transport with dipyridamole or its receptors with methylxanthines, affecting heart rhythm management.

Keywords

Adenosine

Cardiac electrophysiology

G-protein coupled receptors

IKACH

Hyperpolarization