Exam

Heart Rate

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Heart Rate, Electrocardiogram Rate, EKG Rate, Maximal Heart Rate

  • See Also
  1. Vital Signs
  2. Pediatric Vital Signs
  3. Electrocardiogram
  4. Cardiac Electrophysiology Anatomy
  • Interpretation
  • General
  1. Heart Rate may be estimated from a regular pulse
    1. Count pulses for 6 seconds and multiply by 10
    2. Count pulses for 15 seconds and multiply by 4
  2. Maximal Heart Rate predicted by Age (may be used for Exercise target, typically 60-80% of maximum)
    1. Maximal Heart Rate = 220 - Age
    2. Women may be better estimated with St. James Women Take Heart Project Calculation
      1. Maximal Heart Rate = 206 - (Age * 0.88)
      2. Gulati (2010) Circulation 122(2):130-7 +PMID: 20585008 [PubMed]
  3. Heart Rate changes during respiration (respiratory variation)
    1. Heart Rate increases during inspiration
    2. Heart Rate decreases during expiration
  • Interpretation
  • Estimate from EKG Tracing
  1. Count Complexes in a 6 second EKG or Telemetry strip
    1. Normal recording is 25 mm/sec (5 large boxes per second, 30 per 6 seconds)
    2. Distance markers on EKG represent 15 large boxes (3 seconds)
    3. Count QRS Complexes between spanning 2 distance markers (30 large boxes, 6 seconds)
    4. Multiply complex count by 10 for Heart Rate per minute
  2. Interval between complexes
    1. Count large boxes (0.2 seconds) between complexes
    2. Divide 300 by box count: 300, 150, 100, 75, 60, 50
      1. 1 large box (200 ms or 0.2 seconds): 300 bpm
      2. 2 large boxes (400 ms or 0.4 seconds): 150 bpm
      3. 3 large box (600 ms or 0.6 seconds): 100 bpm
      4. 4 large boxes (800 ms or 0.8 seconds): 75 bpm
      5. 5 large box (1000 ms or 1.0 seconds): 60 bpm
      6. 6 large boxes (1200 ms or 1.2 seconds): 50 bpm
      7. 7 large box (1400 ms or 1.4 seconds): 43 bpm
      8. 8 large boxes (1600 ms or 1.6 seconds): 37 bpm
  • Interpretation
  • Background
  1. Intrinsic Rates
    1. Atria: 75
    2. AV Node: 60
    3. Ventricle: 40
  2. Rough estimates to remember
    1. Infant: 160
    2. Preschool: 120
    3. Teen: 100
  3. Normal Heart Rate for age
    1. Infant: 100-160
    2. Toddler: 90-150
    3. Preschool: 80-140
    4. School-age: 70-120
    5. Teen and adult: 60-100
  4. References
    1. Diekmann (2006) Pediatric Education for Prehospital Professionals, Jones and Bartlett
  • Interpretation
  1. Bradycardia: under 60 (adults, see pediatric range above)
  2. Normal Sinus Rhythm: 60 to 100 (adults, see pediatric range above)
  3. Narrow Complex Tachycardia
    1. Sinus Tachycardia: over 100
    2. Supraventricular Tachycardia
      1. Infants: over 220
      2. Children: over 180
      3. Adults: over 160
  4. Wide Complex Tachycardia
    1. Ventricular Tachycardia
    2. Supraventricular Tachycardia with aberrancy