cases of ecg interpretation

1. CENTRE FOR PHYSIOTHERAPY AND REHABILITATION SCIENCES
JAMIA MILLIA ISLAMIA
TOPIC - CASES OF ECG INTERPRETATION
SUBJECT – PHYSIOTHERAPY IN CARDIOPULMONARY CONDITIONS
SUBJECT CODE – BPT 402
SUBMITTED TO – DR. JA,MAL ALI MOIZ
SUBMITTED BY – ANHA ALI
ENROLLMENT NO- 17-7387
ROLL NO.- 17BPT004
DATE – 16-02-21

2. ECG GRIDE AND NORMAL VALUES
• In ECG paper the fine lines marked 1mm apart, bold lines are 5mm apart
• During ECG recording , the usual paper speed is 25mm per second , means 25 small square are covered
in one second , thus one small square is 1/25 or 0.04 seconds and the width of large square is 0.20
second
• Normally 1 millivolt signals from the machine produce a 10 milimeter vertical deflection thus each
small square on a vertical axis represent 0.1mV and each large square represent 0.5 mV

3. Normal P Wave
• Small round wave produced by atrial depolarization, reflects the sum of right and left artrial activation
P wave normally upright in most of ECG leads with two exception
i) In lead aVR1 it is inverted along with inversion of the QRS complex and the T Wave, as direction of
artrial wave away from lead
ii) In lead V1, it is generally biphasic that is upright but with a small terminal negative deflection
representing left atrial activation in reverse direction
• Normally P Wave has a single peak without a gap or notch between the right and left atrial components .
• A normal P Wave meets the following criteria
o Less then 2.5 mm (0.25 mV) in height
o Less then 2.5 mm (0.10 sec ) in width
Normal QRS complex
• The QRS complex is major positive deflection on the ECG produced
by ventricular depolarization
• The Q Wave is not visible in all ECG lead. Physiological Q wave
may be observed in leads L1, aVL, V5, V6
The physiological Q wave meet the following criteria:
o less then 0.04 sec in width
o less then 25% of R wave
• The R wave is major positive deflection of the QRS complex, it is upright in most leads except in lead
aVR where P wave and T wave are also inverted

4. • Normally R wave voltage gradually increases as we move from lead V1 to lead V6 known as normal R
wave progression in precordial leads.
• Normally R wave amplitude does not exceed 0.4 mV (4mm) in lead V1 where it reflect spatial activation
and does not exceed 2.5 mV in lead V6 where it reflect left ventricular activation.
• The r wave is smaller then S wave in lead V1 and the R wave is taller then the s wave in lead V6
• In lead V1 S wave reflect left ventricular activation while in a lead V6 the s wave reflect right ventricular
activation , thus S wave magnitude is greater then r wave height in lead V1 and the s wave is smaller than
the R wave in lead V6
• Normal value of s wave voltage does not be exceed 0.7mV
• the normal QRS complex is narrow, has a sharp peak and measure less then 0.08 sec ( 2mm) on
horizontal axis.
Normal T Wave
• large rounded wave produced by ventricular repolarization, normally upright
in most leads except in lead aVR
• The normal T wave is taller in lead V6 then in lead V1 . The amplitude
of the normal T wave does not generally exceeds 5mm in the limb leads and
10 mm in the precordial leads

5. Normal U Wave
• The U wave is a small rounded wave produced by slow and later repolarization of the intraventricular
Purkinje system . It is much smaller then T wave
• It is often difficult to notice U wave but when seen it is best appreciated in the precordial leads V2 to V4
• It is easy to recognize when Q-T interval is short or heart rate is slow.
Normal P-R interval
• Measured on the horizontal axis from the onset of P wave to the beginning of QRS complex irrespective of
whether it begins with Q wave or R wave
• It measures Atrioventricular (AV) conduction time
• Normal range is 0.12 to 0.20 sec. depending on heart rate
• It is prolonged at slow HR and shortened at fast HR
Normal QT interval
• Measured on horizontal axis from the onset of Q wave to the end of T wave
• QT interval denotes total duration of ventricular systole
• Normal ranges is 0.35 to 0.43sec
• Shorter in younger individual and longer in elderly.
• Shorter at fast HR and lengthen at the slow HR T

6. NORMAL ECG
A normal ECG is illustrated above . Heart beat is 60 – 100 beats per minute
1. P wave:
• upright in leads I, aVF and V3 - V6
• normal duration of less than or equal to 0.11 seconds
• polarity is positive in leads I, II, aVF and V4 - V6; diphasic in leads V1 and V3; negative in aVR
• shape is generally smooth, not notched or peaked

7. 2. QRS complex:
• small septal Q waves in I, aVL, V5 and V6 (duration less than or equal to 0.04 seconds; amplitude less
than 1/3 of the amplitude of the R wave in the same lead).
• represented by a positive deflection with a large, upright R in leads I, II, V4 - V6 and a negative
deflection with a large, deep S in aVR, V1 and V2
• in general, proceeding from V1 to V6, the R waves get taller while the S waves get smaller. At V3 or
V4, these waves are usually equal. This is called the transitional zone.
3..ST segment:
• isoelectric, slanting upwards to the T wave in the normal ECG
• can be slightly elevated (up to 2.0 mm in some precordial leads)
• never normally depressed greater than 0.5 mm in any lead
4.. T wave:
• T wave deflection should be in the same direction as the QRS complex in at least 5 of the 6 limb leads
• normally rounded and asymmetrical, with a more gradual ascent than descent
• should be upright in leads V2 - V6, inverted in aVR
• amplitude of at least 0.2 mV in leads V3 and V4 and at least 0.1 mV in leads V5 and V6
• isolated T wave inversion in an asymptomatic adult is generally a normal variant
5.. QT interval:
• Durations normally less than or equal to 0.40 seconds for males and 0.44 seconds for females.

8. CASES
1. ARTRIAL AND VENTRICULAR ENLARGEMENT
A. RIGHT ATRIAL ABNORMALITY
• Overload of the right atrium may produce an abnormally tall P wave (2.5 mm or more).
• Occasionally, right atrial abnormality (RAA) will be associated with a deep (negative) but narrow P wave in
lead V1, due to the relative inferior location of the right atrium relative to this lead.
• The abnormal P wave in RAA is sometimes referred to as P pulmonale
• The tall, narrow P waves characteristic of RAA can usually be seen best in leads II, III, aVF, and
sometimes V1.
• RAA is seen in a variety of important clinical settings. It is usually associated with right ventricular
enlargement. Two of the most common clinical causes of RAA are pulmonary disease and congenital heart
disease. The pulmonary disease may be either acute (bronchial asthma, pulmonary embolism) or chronic
(emphysema, bronchitis). Congenital heart lesions that produce RAA include pulmonary valve stenosis, atrial
septal defects, and teratology of fallot
B. LEFT ATRIAL ABNORMALITY
• Left atrial enlargement (LAE) characteristically produces a
wide P wave with duration of 0.12 sec or
more (at least three small boxes). With enlargement
of the left atrium the amplitude (height) of the
P wave may be either normal or increased.

10. • LAA may occur in Valvular heart disease, particularly aortic stenosis, aortic regurgitation, mitral
regurgitation, and mitral stenosis
• Hypertensive heart disease, which causes left ventricular enlargement and eventually LAA
• Cardiomyopathies (dilated, hypertrophic, and restrictive)
• Coronary artery disease
C. RIGHT VENTRICULAR HYPERTROPHY
• With right ventricular hypertrophy, lead V1 sometimes shows a tall R wave as part of the qR complex.
• Because of right atrial enlargement, peaked P waves are seen in leads II, III, and V1.
• The T wave inversion in lead V1 and the ST segment depressions in leads V2 and V3 are due to right
ventricular overload. The PR interval is also prolonged (0.24 sec).
• Right axis deviation also seen in severe RVH
• An important cause of RVH is congenital heart disease, such as pulmonary stenosis, atrial septal defect .
Patients with long-standing severe pulmonary disease may have pulmonary artery hypertension and RVH.
• Mitral stenosis can produce a combination of LAA and RVH.
D. LEFT VENTRICULAR HYPERTROPHY
There are following criteria have been proposed for the ECG diagnosis of LVH:
1. If the sum of the depth of the S wave in lead V1 (SV1) and the height of the R wave in either lead V5 or V6
(RV5 or RV6) exceeds 35 mm (3.5 mV), LVH should be considered . However, high voltage in the chest
leads is a common normal finding (see fig)
2. Just as RVH is sometimes associated with repolarization abnormalities due to ventricular overload, so ST-T
changes are often seen in LVH

11. • Right ventricular hypertrophy, lead V1 sometimes shows a tall R wave as part of the qR complex.
• Peaked P waves are seen in leads II, III, and V1.
• The T wave inversion in lead V1 and the ST segment depressions in leads V2 and V3
• The PR interval is also prolonged (0.24 sec).

12. •
•
• 2.)
•
• Repolarization abnormality inLVH
• reffered as strain pattern, characte-
• ized by slight ST segment
• depression with T wave inversion
in tall R wave lead
1. Pattern of left ventricular hypertrophy in a patient with severe hypertension. Tall voltages are seen in the
chest leads and lead aVL (R = 17 mm). A repolarization (ST-T) abnormality, formerly referred to as a
“strain” pattern, is also present in these leads. In addition, enlargement of the left atrium is indicated
by a biphasic P wave in lead V1.

13. 2. VENTRICULAR CONDUCTION DISTURBANCES: BUNDLE BRANCH BLOCKS AND
RELATED ABNORMALITIES
A.) RIGHT BUNDLE BRANCH BLOCK
• In RBBB the right ventricular stimulation will be delayed and the QRS complex will be widened.
• The change in the QRS complex produced by RBBB is a result of the delay in the total time needed for
stimulation of the right ventricle when there is a simultaneous depolarization of the left and right ventricles.
(3rd phase)
• This means that after the left ventricle has completely depolarized, the right ventricle continues to
depolarize.
Thus in RBBB, ECG represented as
o Lead V1 show rSR complex with wide R wave
o Lead V6 shows qRS pattern with wide S wave.
RBBB are of 2 types :-
a.) complete RBBB- QRS that is 0.12 sec or more
in with an rSR′ in lead V1 and a qRS in lead V6
b.) incomplete RBBB – shows same QRS pattern but
duration is in between 0.10 – 0.12
• RBBB may be caused by a number of factors, including
atrial septal defect with left-to-right shunting of
blood, pulmonary artery hypertension, coronary
disease and cardiomyopathies

14. B.) LEFT BUNDLE BRANCH BLOCK
• Left bundle branch block (LBBB) also produces a pattern with a widened QRS complex. The QRS
complex with LBBB is very different from that with RBBB. The major reason for this difference is
that RBBB affects mainly the terminal phase of ventricular activation, where as LBBB also affects the
early phase
• When LBBB is present, the septum depolarizes from right to left and not from left to right.
• The first major ECG change produced by LBBB is a loss of the normal septal r wave in lead V1 and
the normal septal q wave in lead V6. the total time for left ventricular depolarization is prolonged with
LBBB. As a result, the QRS complex is abnormally wide.
Thus major ECG changes seen in LBBB is
• Lead V1 usually shows a wide, entirely negative QS
complex (rarely, a wide rS complex).
• Lead V6 shows a wide, tall R wave without a q wave.
Complete LBBB QRS is 0.12 sec or wider
LBBB diagniosed in
• Advanced coronary artery disease
• Valvular heart disease
• Hypertensive heart disease
• Cardiomyopathy

15. 3. MYOCARDIAL INFRACTION
• Transmural MI is characterized by ischemia and ultimately necrosis of a portion of the entire or nearly the entire
thickness of the left ventricular wall. Most patients who present with acute MI have underlying atherosclerotic
coronary artery disease.
• The earliest ECG changes seen with an acute transmural ischemia/infarction typically occur in the ST-T complex in
sequential phases:
o The acute phase is marked by the appearance of ST segment elevations and sometimes tall positive (hyperacute) T
waves in multiple (usually two or more) leads. The term “STEMI” refers to this phase.
o The evolving phase occurs hours or days later and is characterized by deep T wave inversions in the leads that previously
showed ST elevations.
Example . Chest leads from a patient with acute anterior ST segment elevation myocardial infarction (STEMI).
FIG. A, In the earliest phase of the infarction, tall,
positive (hyperacute) T waves are seen in leads V2 to V5.
FIG B, Several hours later, marked ST segment elevation
is present in the same leads (current of injury pattern),
and abnormal Q waves are seen in leads
in V1 and V2.

16. SUMMARY :
 Characteristics of normal ECG
• P wave: upright in leads I, aVF and V3 - V6,normal duration of less than or equal to 0.11 seconds, polarity is
positive in leads I, II, aVF and V4 - V6, diphasic in leads V1 and V3; negative in aVR
• QRS complex: represented by a positive deflection with a large, upright R in leads I, II, V4 - V6 and a
negative deflection with a large, deep S in aVR, V1 and V2
• ST segment – lso electric
• T wave - should be upright in V2- V6, inverted in aVR
 Characteristics of RIGHT ARTRIAL ENLARGEMENT/ ABNORMAILY in ECG
• The tall, narrow P waves seen best in leads II, III, aVF, and sometimes V1.
 Characteristics of LEFT ARTRIAL ENLARGEMENT/ ABNORMAILY in ECG
• Wide P wave with duration of 0.12 sec or more (at least three small boxes), second hump may also seen in P
wave
 Right ventricular hypertrophy ECG changes
• Lead V1 sometimes shows a tall R wave, Peaked P waves are seen in leads II, III, and V1, The T wave
inversion in lead V1 and the ST segment depressions in leads V2 and V3 , The PR interval is also prolonged
 Left ventricular hypertrophy ECG changes
• Repolarization abnormality in LVH referred as strain pattern, characterized by slight ST segment depression
with T wave inversion in tall R wave lead
 Right bundle branch block (RBBB) ECG changes
• Lead V1 show rSR complex with wide R wave ,Lead V6 shows qRS pattern with wide S wave.
 Left bundle branch block (LBBB) ECG changes
• Lead V1 usually shows a wide, entirely negative QS complex (rarely, a wide rS complex), Lead V6 shows a
wide, tallR wave without a q wave.
 MI infraction ECG changes
• In the earliest phase of the infarction, tall,positive (hyperacute) T waves are seen in leads V2 to V5.
• Later stage , marked ST segment elevation is present in the same leads, and abnormal Q waves are seen in
leads in V1 andV2

17. References :
• GOLDBERGERS Clinical Electrocardiography A simplified approach (8th edition) by Zachary D.
Goldberger Alexei Shvilkin
• Hampton, John R. The ECG made easy 2008 eidition , by Churchill Livingstone
• Downie P A . Cash Textbook