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

Workshop 1_Tomaselli_2025_case 1 answer

Video Transcription

Video Summary

The key observation is that cells in panel A, exposed to dofetilide, have longer action potentials that lengthen more at longer pacing cycle lengths compared to cells in panel B. This is because dofetilide lengthens action potential duration and exhibits reverse use-dependency, meaning it causes greater prolongation at slower pacing rates. In contrast, ranolazine and diltiazem shorten action potential duration by blocking specific currents, and amiodarone has minimal impact on action potential duration and frequency dependence.

Keywords

dofetilide

action potential

reverse use-dependency

ranolazine

diltiazem