EKG Interpretation Basics

Introduction

• Speaker: Sarah from registernursern.com
• Topic: Basics of EKG (ECG) interpretation
• Supplementary: Free quiz available to test knowledge

What is an EKG?

• EKG (ECG): Electrocardiogram
• Purpose: Assesses the electrical conduction system of the heart
• Function: Ensures heart contracts and pumps blood efficiently

Heart Blood Flow and Electrical Conduction

• Blood Flow Overview:
  • Right side: Blood enters right atrium → tricuspid valve → right ventricle → pulmonic valve → pulmonary artery → lungs (oxygenation)
  • Left side: Oxygenated blood enters left atrium → mitral valve → left ventricle → aortic valve → aorta
• Electrical Conduction System: Coordinates heart contractions

Key Terms

• Depolarization: Leads to contraction (e.g., atrial depolarization → atrial contraction)
• Repolarization: Leads to relaxation (e.g., ventricular repolarization → ventricular relaxation)

Electrical Conduction Pathway

• SA Node (Sinoatrial Node):
  • Located in the right atrium
  • Known as the heart's pacemaker (60-100 bpm)
  • Causes atrial depolarization
• AV Node (Atrioventricular Node):
  • Acts as a gatekeeper; delays impulses
  • Ensures atria empty into ventricles before ventricles contract
• Bundle of His & Purkinje Fibers:
  • Lead to ventricular contraction

PQRST Complex

• Normal Rhythm: SA node firing leads to a normal sinus rhythm
• P Wave: Atrial depolarization
• PR Segment: Delay by AV node
• PR Interval: Time for impulse from atria to AV node
• QRS Complex: Ventricular depolarization; atrial repolarization occurs simultaneously but is overshadowed
• J Point & ST Segment: Transition from depolarization to repolarization; should be isoelectric (flat)
• T Wave: Ventricular repolarization
• QT Interval: Total time for ventricles to contract and rest

EKG Strip Analysis

• Components of the Strip: Contains small and large squares representing time
  • Small Square: 0.04 seconds
  • Large Square: 0.20 seconds

Analyzing a Rhythm

• Six-second Strip: 30 large squares represent 6 seconds
• Questions to Consider:
  • P Waves: Regularity, Rate, Resemblance
  • QRS Complex: Regularity, Rate, Resemblance
  • T Waves: Position and appearance
  • Check PR Interval, ST Segment, QT Interval

Practical Steps

1. Measure P Waves: Check regularity, count for rate, assess appearance
2. Measure QRS Complex: Assess regularity, calculate rate, evaluate resemblance
3. Evaluate T Waves: Ensure presence and proper shape
4. Check Intervals:
   • PR Interval: 0.12 to 0.20 seconds
   • QRS Complex Duration: < 0.12 seconds
   • QT Interval: 0.35 to 0.44 seconds
   • ST Segment: Should remain flat

Conclusion

• Example Walkthrough: Step-by-step analysis of a sample EKG strip leading to normal sinus rhythm determination
• Further Learning: Additional videos available via provided link