Notes on Atria and Ventricle Repolarization and Depolarization

Introduction

• Presenter: Sarah from registerednessrn.com.
• Topic: Review of atria and ventricle repolarization and depolarization.
• Objective: Understanding the electrical conduction system essential for EKG interpretation and the PQRST complex.

Key Concepts

Electrical Conduction System

• Essential for sending electrical signals targeting atrial and ventricular cells to contract and relax.
• Repolarization and Depolarization: Crucial processes for heart cell activity.

Heart Cell Dynamics

• Resting Heart Cell:
  • Negatively charged on the inside (polarized state).
  • Different ion concentrations inside vs. outside.
  • Membrane is impermeable to sodium (Na+).
• Depolarization:
  • Triggered by a jolt of electricity from the conduction system.
  • Sodium enters the cell, changing it to a less negative charge (more positive).
  • Leads to contraction of the heart cell.
• Repolarization:
  • Follows contraction, returning the cell to its negative state (relaxation).
  • Remember: "Relax" starts with "Re" as does "Repolarization".

Atrial and Ventricular Contraction/Relaxation

• Atrial Depolarization: Refers to atrial contraction.
• Ventricular Repolarization: Refers to ventricular relaxation.

PQRST Complex Breakdown

• Section 1 (P Wave): Atrial depolarization begins (atria contract).
• Section 2 (PR Segment): Atrial depolarization completes.
• Section 3 (QRS Complex): Ventricular depolarization begins; includes unseen atrial repolarization.
• Section 4 (ST Segment): Ventricular depolarization completes.
• Section 5 (T Wave): Ventricular repolarization begins.
• Section 6 (Isoelectric Line): Ventricular repolarization completes.

Conclusion

• Recap of how depolarization and repolarization occur in the PQRST complex.
• For further learning, access additional ECG interpretation videos via the provided YouTube link.