EKG Interpretation Basics

Introduction

• Presenter: Sarah Thurston, NurseRN.com
• Focus: Basics of EKG (electrocardiogram) interpretation
• Purpose: Understand EKG interpretation and test knowledge with a free quiz after the video

EKG Overview

• EKG (Electrocardiogram): Assesses the electrical conduction system of the heart
• Purpose: Ensure the heart contracts and pumps blood throughout the body

Blood Flow in the Heart

1. Right Side of Heart
   • Blood enters right atrium (needs oxygen)
   • Right atrium contracts, blood moves to right ventricle via tricuspid valve
   • Right ventricle contracts, blood moves to lungs via pulmonic valve
   • Gas exchange occurs in lungs, blood gets oxygenated
2. Left Side of Heart
   • Oxygenated blood enters left atrium via pulmonary vein
   • Left atrium contracts, blood moves to left ventricle via mitral valve
   • Left ventricle contracts, blood moves to aorta via aortic valve, supplying body with oxygenated blood

Electrical Conduction System

• Role: Send electrical signals to heart cells for contraction and relaxation
• Requires understanding of depolarization and repolarization

Heart Cell Dynamics

• Resting State: Negative charge inside (polarized)
• Depolarization:
  • Triggered by electrical jolt, membrane permeability changes, sodium enters cell
  • Leads to contraction
• Repolarization: Returns to negative state, leads to relaxation

Electrical Conduction Pathway

• SA Node (Sinoatrial Node): Pacemaker, located in right atrium, initiates atrial contraction
• AV Node (Atrioventricular Node): Gatekeeper, delays impulses to allow atria to empty before ventricles contract
• Bundle of His: Pathway for ventricle depolarization, leading to contraction
• Bundle Branches & Purkinje Fibers: Spread impulse through ventricles
• PQRST Complex: Represents electrical conduction visualized on EKG

Analyzing EKG Strips

1. EKG Paper Basics:
   • Small squares: 0.04 seconds
   • Large squares: 0.20 seconds
2. PQRST Complex Components:
   • P Wave: Atrial depolarization
   • PR Segment: Delay by AV node
   • QRS Complex: Ventricular depolarization
   • ST Segment: Transition from depolarization to repolarization
   • T Wave: Ventricular repolarization
   • QT Interval: Duration of ventricular cycle
3. Measurements to Note:
   • P Wave: < 0.12 seconds
   • PR Interval: 0.12 to 0.20 seconds
   • QRS Complex: < 0.12 seconds
   • ST Segment: Should be flat
   • QT Interval: 0.35 to 0.44 seconds

Analyzing Rhythms

• Method: Use 6-second EKG strip, check regularity, rate, and resemblance of P waves and QRS complexes
• Check Regularity: Use calipers or paper to ensure equal distances between waves
• Rate Calculation: Count waves in 6 seconds, multiply by 10
• Resemblance: Ensure proper wave shapes and intervals
• Normal Sinus Rhythm: Identified by regular measurements and intervals

Conclusion

• Summary: Reviewed basic EKG interpretation and application
• Additional Resources: More videos available through YouTube link in description