Introduction to ECGs

1
Introduction to ECGs

• EMS Technology
• Temple College

2
Discussion Topics

• Standardized Methods Devices
• Components Measurements of the ECG Complex
• Component Associations
• Rhythm Assessment Format

3
Standardized Methods Devices

• ECG Paper
• Device Paper Speed
• Device Calibration
• Electrode Placement
• Variations Do Exist!

4
Standardized Methods Devices

• ECG Graph Paper
• Vertical axis- voltage1 small box 1 mm
• Horizontal axis - time1 small box 1 mm 0.04
  sec.
• Every 5 lines (boxes) are bolded
• Horizontal axis - 1 and 3 sec marks

5
Standardized Methods Devices

• ECG Paper Examples
• Vertical Axis
• No. of mm in 10 small boxes?
• No. of small boxes in 2 mm?
• Horizontal Axis
• No. of seconds in 5 small boxes?
• No. of small boxes in 0.2 second?
• No. of small boxes in 1 second?

6
Standardized Methods Devices

• Paper Speed Calibration
• Paper Speed - 25 mm/sec standard
• Calibration of Voltage is Automatic
• Both Speed and voltage calibration can be changed
  on most devices

7
Standardized Methods Devices

• Electrode Placement
• Standardization improves accuracy of comparison
  ECGs
• 3 Lead and 12 Lead Placement are most common
• Avoid
• Bone
• Moving muscle
• Limb best but more artifact

8
Components of the ECG Complex

• Components Their Representation
• P, Q , R, S, T Waves
• PR Interval
• QRS Interval
• ST Segment

9
Components of the ECG Complex

• Normal Values
• PRI 0.12 - 0.20 seconds
• QRS Interval lt 0.12 seconds
• Ventricular rate 60-100 (adult)

10
Component Association

• Specific associations found with normal ECG
• Normal P wave before each complex (Indicative
  of?)
• Relationship of P wave to QRS complex is 11
  (Indicative of?)
• ST segment visible
• Distinct isoelectric line, waves intervals

11
ECG Rhythm Assessment Format (3 Lead)

• Rate (3 methods)
• Regularity (RR interval)
• Components Relationships
• Waves (Present? Alike?)
• Intervals
• PRI QRS duration
• PQRS relationship
• Consistent?
• Extras? Other Info?

12
ECG Rhythm Assessment Format (3 Lead)

• Clues
• Normal vs. Abnormal rate
• AV association vs. dissociation
• PQRS
• R-R
• Pacemaker site
• QRS Duration
• PQRS relationship and PRI
• Premature complexes

13
Practice

• Textbook, PP. 38-39, 40-44, 61-66
• Identifying Components
• Determining Rates using various methods
• Determining Regularity the degree of
  Irregularity
• Measuring intervals and durations

14
Lab

• Device Familiarization (LifePak 10, Codemaster
  100, Zoll )
• Power (Batteries, Warnings)
• Electrical Rate vs. Mechanical (common error with
  counting QRS)
• Printing
• Failures
• Electrode Placement
• Causes of Artifact
• Examples