13. ECG waves
P wave-atrial depolarization
QRS complex-ventricular
depolarization
ST segment,T wave-
ventricular repolarization
14.
15. PWAVE
Atrial depolarization
Always positive in lead I and II
Always negative in lead aVR
< 3 small squares in duration
< 2.5 small squares in amplitude
Commonly biphasic in leadV1
Best seen in leads II,v1
22. TWAVE
NormalT wave is asymmetrical, first half
having a gradual slope than the second
Should be at least 1/8 but less than 2/3 of the
amplitude of the R
T wave amplitude rarely exceeds 10 mm
AbnormalT waves are symmetrical, tall,
peaked, biphasic or inverted.
T wave follows the direction of the QRS
deflection.
33. ST SEGMENT
ST Segment is flat
(isoelectric)
• Elevation or
depression of ST
segment by mm or more
• “J” (Junction) point is
the point between QRS
and ST segment
34.
35.
36.
37. Causes of ST Segment Elevation
Acute myocardial infarction
Coronary vasospasm (Printzmetal’s angina)
Pericarditis
Benign early repolarization
Left bundle branch block
Left ventricular hypertrophy
Ventricular aneurysm
Brugada syndrome
Ventricular paced rhythm
Raised intracranial pressure
38. Causes of ST Depression
Myocardial ischaemia / NSTEMI
Reciprocal change in STEMIPosterior MI
Digoxin effect
Hypokalaemia
Supraventricular tachycardia
Right bundle branch block
Right ventricular hypertrophy
Left bundle branch block
Left ventricular hypertrophy
Ventricular paced rhythm
41. DEWINTERTWAVE
Diagnostic Criteria
•Tall, prominent, symmetric T waves in the precordial leads
•Upsloping ST segment depression >1mm at the J-point in the precordial leads
•Absence of ST elevation in the precordial leads
•ST segment elevation (0.5mm-1mm) in aVR
•“Normal” STEMI morphology may precede or follow the deWinter pattern
45. UWAVE
small, round, symmetrical and
positive in lead II, with amplitude <
2 mm
U wave direction is the same as
T wave
More prominent at slow heart rates
46. Inverted U waves
• U-wave inversion is abnormal (in leads with
upright T waves)
• A negative U wave is highly specific for the
presence of heart disease
▪ Common causes of inverted U waves
• Coronary artery disease
• Hypertension
• Valvular heart disease
• Congenital heart disease
• Cardiomyopathy
• Hyperthyroidism
47. ▪ In patients presenting with chest pain,
inverted U waves:
• Are a very specific sign of myocardial
ischaemia
• May be the earliest marker of unstable
angina and evolving myocardial infarction
48. QT INTERVAL
1.Total duration of Depolarization and Repolarization
2. QT interval decreases when heart rate increases
3. For HR = 70 bpm, QT<0.40 sec.
4. QT interval should be 0.350.45s,
5. Should not be more than half of the interval between adjacent R waves
(RR interval).
69. RATE
Normal from 60-100
Rate
If regular
________ 300____________
Number of big square bet.RR
If irregular
a) Count 30 big square
b) Count number of R waves inside 30 big square.
c) Number of R X 10 = HR/min
70.
71.
72.
73.
74.
75. RYTHM
ASKYOURSELF 4 QUESTION
▪ Are there normal P waves present?
▪ Are the QRS complexes wide or narrow?
▪ What is the relationship between the P waves
and QRS complexes?
▪ Is the rhythm regular or irregular?
76. Assess the P waves
- Are there P waves?
- Does the P waves all look alike?
- Does the P waves occur at a regular rate?
- Is there one P wave before each QRS?
Interpretation? Normal P waves with 1 P
wave for every QRS
96. INFERIOR MI
How to recognise an
inferior STEMI
ST elevation in leads II, III
and aVF
Progressive development of
Q waves in II, III and aVF
Reciprocal ST depression in
aVL (± lead I)
97.
98.
99.
100.
101. ANT STEMI
How to Recognise Anterior
STEMI
ST segment elevation with Q
wave formation in the precordial
leads (V1-6) ± the high lateral
leads (I and aVL).
Reciprocal ST depression in the
inferior leads (mainly III and
aVF).
102.
103.
104.
105.
106. POST MI
Posterior MI is suggested by
the following changes in V1-3:
Horizontal ST depression
Tall, broad R waves (>30ms)
Upright T waves
Dominant R wave (R/S ratio
> 1) in V2
115. NSR Parameters
- Rate:- 60 - 100bpm
- Regularity rhythm :-regular
- P wave:- Normal
• - PR interval :- 0.12 - 0.20 s
- QRS duration :- 0.04 - 0.12 s
Any deviation from above is sinus tachycardia, sinus bradycardia or an
arrhythmia
131. VentricularTachycardia
Criteria
Rate : Generally 100 to 220 bpm
Rhythm : Generally regular, on occasions, can be modestly irregular.
P wave : Absent
QRS : Broad and bizarre indicating that QRS complexes are arising from
complex ventricles
Capture : Appearance of normal QRS complex in the middle of
ventricular beat tachycardia
Fusion beat : This type of complex is caused by two pacemakers, SA
node and ventricular pacer. The result is hybrid of fusion complex,
which is a complex with some features of both
134. Criteria
▪ Rate : Very rapid, too disorganized to count.
Arround 350–500 bpm
▪ Rhythm : Irregular, waveform varies in size and
shape
▪ QRS : QRS complexes are wide, bizarre and
irregular
▪ complexes Absent ST segments, P waves, T
waves
