This document provides a 7-step approach to interpreting electrocardiograms (ECGs). The steps include: 1) assessing heart rate, 2) determining heart rhythm, 3) identifying the electrical heart axis, 4) measuring the PR interval, 5) analyzing the QRS complex, 6) examining repolarization in the ST-T segment, and 7) evaluating the R/S ratio. Common arrhythmias and abnormalities are described under each step along with their characteristic ECG patterns and management approaches. Assessment techniques using a caliper, pen and paper are recommended to accurately measure intervals and analyze rhythms and complexes.

1. Dr.Sherif Magdy
ECG Simple Approach

2. How to Interpret an ECG
in 7 Steps

3. Step 1: Heart Rate
Step 2: Heart Rhythm
Step 3: Electrical Heart AXIS
Step 4: The PR Interval
Step 5: The QRS Complex
Step 6: Repolarization ST-T
Step 7: The R/S Ratio

4. 1-Heart Rate

5. Before you
start
Look at speed
25 mm/s.

6. Caliper & speed

7. RATE
Rule of 300

10. Sinus Tachycardia

Normal Sinus Rhythm with HR > 100
Management : treat the cause.

11. Supraventricular Tachycardia ( SVT )
• Regular , HR > 150 !!
• No P or retrograde P
Management :
1- Cardioversion ( DC, Medical )
3- Radiofrequency ablation.

13. Atrial flutter
• Regular + saw tooth P wave
• may be irregular if there is variable block in AV node
Management : ( like AF, transient rhythm )
1- Cardioversion ( medical , electrical )
2- Rate control ( BB, CCB , Digoxin )
3- Anticoagulation

14. Ventricular Tachycardia ( VT, V Tach )
HR > 100 , Wide QRS > 3 small , AV
dissociation
Sustained VT : run of more than 30 s
Non-sustained VT : run of less than 30 s
Management :
Cardioversion :
1- DC cardioversion.
2- Medical ( Amiodarone, Lidocain )

16. 2-Heart Rhythm

17. Rhythm

Regular OR irregular

18. Pen & Paper

19. 3- AXIS

23. 4-The PR Interval

24. PR Interval
Normal: 0.12 - 0.20 seconds
(3 to 5 small boxes)

26. 5-The QRS Complex

28. Left Ventricular Enlargement
R ( in V5 or V6 )
> 35 ss (7 large
large)
+ Lt axis
S ( in V1 or V2 )
+

29. Right Ventricular Enlargement
R > S in
V1
S > R in
V6
+ Rt axis

31. RVH with Strain

32. QRS duration
Normal: 0.04 - ≤ 0.10 seconds.
( ≤ 2.5 boxes)

33. Bundle Branch Block
Simple method
Wide QRS complex---- BBB
Look to V1
If mainly +ve complex R ------- RBBB
If mainly -ve complex ---------- LBBB

36. Remember

if V1 is +ve

Some thing Right

RBBB or RVH

37. 6- Repolarization ST-T

38. Myocardial
Ischemia
and
Infarction

39. ST SEGMENT

40. Ischemic ECG Changes
• ST segment elevation.
• ST segment depression.
• T wave flatting and inversion.
• Pathological Q wave.

41. Stages of STEMI
1- Hyperacute T wave : Tall broad T wave.
2- ST segment elevation.
3- Q wave formation ( may occur early ) .
then T wave inversion & and ST Normalization.
1 2
3

48. R wave
progression
7-The R/S Ratio

53. Simply at the end

54. don’t small us in front of
profs
Remember
Men are parkings
‫للترجمة‬ ‫عبيد‬ ‫انيس‬ ‫معامل‬
From the end