ECG (Main)

Measurement

All these measures are valid for the standard paper speed of 25 mm/Sec

• 1 small box = 1mm = 0.04 sec = 40 miliseconds
• 5 small boxes = 1 big box = 5mm = 0.2 sec = 200 miliseconds
• Standard 12 lead ECG duration = 10 seconds

Interval	Time(s)	Boxes
PR	0.12 - 0.20	3-5
QRS	0.06 - 0.10	1.5-2.5
QTc	<0.44	N/A

Primary Analysis

• ECG Rhythms
• ECG Axis
• Low ECG voltage

Segments & Intervals

• ST Elevation
• ST Depression
• QT Prolongation

Waves

• Q Waves
• T Waves
• R-wave in V1
• Wide QRS

Hypertrophy/Enlargement

Cardiac Hypertrophy and Enlargement

• Right atrial enlargement
• Left atrial enlargement
• Left ventricular hypertrophy
• Right ventricular hypertrophy

AV Blocks

AV Blocks

• First degree AV block
• Second degree AV block type I (Wenkebach)
• Second degree AV block type II
• Third degree AV block
• AV dissociation without complete heart block

Bundle and Fascicular Blocks

• Right Bundle Branch Block
• Left Bundle Branch Block
• Left Anterior Fascicular Block
• Left Posterior Fascicular Block

See Also

• ACS - Anatomical Correlation
• ECGs by Diagnosis
• STEMI equivalents
• Early Repolarization

External Links

• DDxOf: ECG Guide

References

Authors

Ross Donaldson, Daniel Eggeman, Tom Fadial, Abdus Salam Khan, Neil Young, Michael Hwang, Michael Holtz, Daniel Ostermayer, Kevin Lu