Understanding Cardiovascular Diagnostic Tests

Sep 11, 2024

Cardiovascular Diagnostic Tests Lecture Notes

Introduction

  • Presenter: Cathy from Level Up RN
  • Focus: Diagnostic tests related to the cardiovascular system
  • Quiz at the end to test knowledge
  • Reference materials: Medical Surgical Nursing Second Edition and Lab Values Flashcard Deck

Cardiac Enzymes

  • Purpose: Released in response to ischemia during myocardial infarction
  • Key Enzymes:
    • CKMB
      • Found in cardiac muscle
      • Normal: 0%
      • Elevation indicates heart muscle damage
      • Elevated 3-6 hours post-damage, lasts 2-3 days
    • Myoglobin
      • Found in heart and skeletal muscle
      • Normal: <90
      • Elevation could indicate heart or skeletal muscle damage
      • Elevated 2-3 hours post-damage, lasts 24 hours
    • Troponin T and I
      • Specific proteins in heart muscle fibers
      • Troponin T: Normal <0.1
      • Troponin I: Normal <0.03
      • Elevation indicates heart damage
      • Elevated 2-3 hours post-damage
      • Troponin T lasts elevated for 2 weeks (T for two)
      • Troponin I lasts elevated for 1 week (I looks like Roman numeral I)

Cholesterol Levels

  • Total Cholesterol: <200
  • LDL (Low-Density Lipoprotein)
    • "Lousy" cholesterol
    • Normal: <130, <100 if high cardiovascular risk
  • HDL (High-Density Lipoprotein)
    • "Happy" cholesterol
    • Females: >55, Males: >45
  • Triglycerides
    • Females: 35-135
    • Males: 40-160

Blood Pressure

  • Expected: Systolic <120, Diastolic <80
  • Note: Prehypertension, Stage 1 & 2 hypertension, and hypertensive crisis ranges vary by source

Additional Lab Values

  • Red Blood Cells (RBC)
    • Females: 4.2-5.4
    • Males: 4.7-6.1
  • Platelets: 150,000-400,000
  • Hemoglobin
    • Females: 12-16
    • Males: 14-18
  • Hematocrit
    • Females: 37-47%
    • Males: 42-52%
    • Tip: Hematocrit is approximately 3x hemoglobin
  • APTT (Activated Partial Thromboplastin Time)
    • Measures intrinsic and common pathways
    • Normal: 30-40 seconds
    • On heparin: 45-80 seconds (1.5-2x normal)
  • PT (Prothrombin Time) and INR
    • PT Normal: 11-13 seconds, Warfarin: 17-26 seconds
    • INR Normal: ~1, Warfarin: 2-3
  • D-dimer
    • Normal: <0.4
    • Elevated in presence of clots (DVT, PE)
  • HBNP
    • Normal: <100
    • Elevated indicates heart failure due to fluid overload

Quiz

  1. Which cardiac enzyme is most specific for diagnosing heart ischemia?
    • Answer: Troponin
  2. What is the normal range for platelets?
    • Answer: 150,000 to 400,000
  3. What lab value is elevated in the presence of a clot?
    • Answer: D-dimer

Conclusion

  • Encouragement to like, comment, and subscribe to the channel
  • Invitation to share video with classmates and friends in nursing school.