Introduction to ECGs
EMS Technology
Temple College
Discussion Topics
Standardized Methods & Devices
Components & Measurements of
the ECG Complex
Component Associations
Rhythm Assessment Format
Standardized Methods &
Devices
ECG Paper
Device Paper Speed
Device Calibration
Electrode Placement
Variations Do Exist!
Standardized Methods &
Devices
ECG Graph Paper
Verticalaxis- voltage;
1 small box = 1 mm
Horizontalaxis - time;
1 small box = 1 mm = 0.04 sec.
Every 5 lines (boxes) are bolded
Horizontal axis - 1 and 3 sec marks
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?
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
Standardized Methods &
Devices
Electrode Placement
Standardizationimproves accuracy
of comparison ECGs
3 Lead and 12 Lead Placement are
most common
Avoid
Bone
Moving muscle
Limb best but more artifact
Components of the ECG
Complex
Components & Their
Representation
P, Q , R, S, T Waves
PR Interval
QRS Interval
ST Segment
Components of the ECG
Complex
Normal Values
PRI = 0.12 - 0.20 seconds
QRS Interval < 0.12 seconds
Ventricular rate = 60-100 (adult)
Component Association
Specific associations found with
normal ECG
Normal P wave before each
complex (Indicative of?)
Relationship of P wave to QRS
complex is 1:1 (Indicative of?)
ST segment visible
Distinct isoelectric line, waves &
intervals
ECG Rhythm Assessment
Format (3 Lead)
Rate (3 methods)
Regularity (R:R interval)
Components & Relationships
Waves (Present? Alike?)
Intervals
PRI& QRS duration
P:QRS relationship
Consistent?
Extras? Other Info?
ECG Rhythm Assessment
Format (3 Lead)
Clues
Normalvs. Abnormal rate
AV association vs. dissociation
P:QRS
R-R
Pacemaker site
QRS Duration
P:QRS relationship and PRI
Premature complexes
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
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