Transcript ECG Leads

ECG
Dr. Amal Al Maqadma
Teaching assistant
IUG
MI
When myocardial blood supply is abruptly reduced to
a region of the heart, a sequence of injurious events
occur :
 Ischemia ( subendocardial or
transmural)
 Injury
 Necrosis, and eventual fibrosis
(scarring) if the blood supply isn't
restored in an appropriate period of
time
Hyperacute T wave is the earliest sign of
acute myocardial infarction
Precordial Septal Leads
 V1 – V2
– Look at the
Septum of
the heart
– The septal
branch of the
LAD
Precordial
Anterior Leads
 V3 – V4
–anterior wall
of the left
ventricle
–The LAD
diagonal
branch)
Anterior-Septal Terminology
Lateral Precordial Leads
 I,AVL,V5 – V6
 lateral of the
left ventricle
 The left
circumflex
Inferior border leads
 II, III and aVF
 the Inferior wall
of the RV
 Posterior
Descending
Branch of the
RCA.
Posterior MI
 No leads look at the posterior wall.

usually associated with inferior and/or lateral wall MI.

The changes of posterior myocardial infarction are seen
indirectly in the anterior precordial leads. Leads V1 to V3 face
the endocardial surface of the posterior wall of the left
ventricle. As these leads record from the opposite side of the
heart instead of directly over the infarct, the changes of
posterior infarction are reversed in these leads. The R waves
increase in size, becoming broader and dominant, and are
associated with ST depression and upright T waves. This
contrasts with the Q waves, ST segment elevation, and T wave
inversion seen in acute anterior myocardial infarction.

ST depression is considered reciprocal ECG changes in what
should be ST elevation for acute posterior wall injury.
ECG Leads - Views of the Heart
lead
V3 & V4
V1 & V2
a VL,V5 & V6
II+III+AVF
border
Arterial
supply
anterior Right RCA
Ventricle
Septum
LAD
Lateral Left
LCX
Ventricle
inferior
RCA
borderof right
ventricle
Principles of ECG recording
 Explain the indication and the procedure for
the patient. (assurance )
 Ask the patient to take off any metals he/she
wears.
 Expose the wanted sites.
 Cleaning of skin and shaving if necessary.
 Place the electrodes in the correct positions .
 Instruct the patient to remain still (should not
talk during the test ) and relax their shoulders
and legs while the recording takes place (1
min)
 See video
How to comment on ECG
 Name.Age ,Date and time.
 Calibration and Speed of paper
 RAWIHI :
RAWIHI
 R: rate, regularity,rhythm(sinus or
asinus),
 A: axis.
 W:waves.
 I :intervals.
 H: hypertrophy.
 I: ischemia
Normal Sinus Rhythm








Rate = 60-100 beat / minute.
The rhythm is regular
All intervals are within normal limits
There is a P for every QRS and a QRS for
every P.
P : QRS ratio = 1 : 1.
The P waves all look the same
Presence of P, QRS, T in each cycle.
Normal shape, time of waves, segments
and intervals
Interfering factors
Inaccurate placement of the electrodes
Electrolyte imbalances
Poor contact between the skin and the
electrodes
Movement or muscle twitching during the test
Drugs that can affect results include digitalis,
quinidine, and barbiturates