Ekg Axis - Hypertrophy And Enlargement

Front 1

An increase in muscle mass

Back 1

hypertrophy

Front 2

What is the cause of most heart chamber hypertrophy?

Back 2

pressure overload
(pumping against increased resistance)

Front 3

What is another term for dilation of a particular heart chamber?

Back 3

enlargement

Front 4

What is typically the cause of heart chamber enlargement?

Back 4

volume overload
(increased amount of blood in chamber)

Front 5

True or False:
EKG is very efficient at distinguishing between hypertrophy and enlargement.

Back 5

False

Front 6

True or False:
On the EKG, it is common to speak of "atrial hypertrophy."

Back 6

False.
It is traditional to speak of "atrial enlargement" within the context of EKG readings.

Front 7

True or false:
It is traditional to speak of "ventricular hypertrophy" despite the fact that enlargement and hypertrophy of the ventricles may be indistinguishable on EKG.

Back 7

True

Front 8

What is another commonly used term for atrial enlargement on EKG.

Back 8

atrial abnormalities

Front 9

Name the three things that can happen to a wave on EKG when a chamber hypertrophies or enlarges.

Back 9

(1) Increase in duration
(2) Increase in amplitude
(3) Electrical axis shift

Front 10

What term describes the average vector of all instantaneous vectors recorded by EKG?

Back 10

the mean vector

Front 11

What term refers to the direction of the mean vector on EKG?

Back 11

the mean electrical axis

Front 12

On which plane of the EKG is axis defined?

Back 12

frontal plane

Front 13

True or False:
The horizontal plane defines the axis.

Back 13

False.
Axis is defined on the frontal plane only.

Front 14

What is the range of the normal QRS axis?

Back 14

90 degrees to 0 degrees

(or 90 to negative 30,
according to most cardiologists)

Front 15

Which two leads are used to quickly determing whether the QRS axis on any EKG is normal?

Back 15

Lead I and AVF

Front 16

True or False:
Lead I and AVF negative deflections indicate a normal QRS axis.

Back 16

False.
Positive deflections on Lead I and AVF are consistent with a normal axis.

Front 17

True or False:
If the QRS complex is positive in leads I and AVF, the QRS axis MUST be normal.

Back 17

True.

Front 18

True or False:
If the QRS complex in either lead I or AVF is not predominantly positive, the QRS axis is not normal.

Back 18

True.

Front 19

If Lead I is negative and AVF is negative, define the axis.

Back 19

extreme right axis deviation

Front 20

If Lead I is negative and AVF is positive, define the axis.

Back 20

right axis deviation

Front 21

If Lead I is positive and AVF is negative, define the axis.

Back 21

left axis deviation

Front 22

If Lead I is positive and AVF is positive, define the axis.

Back 22

normal axis

Front 23

What kind of deflections would you expect on Lead I and AVF on a normal EKG?

Back 23

predominantly positive

Front 24

What is the normal P wave axis in adults?

Back 24

between 0 and 70 degrees

Front 25

What is the normal P wave axis in children?

Back 25

between 0 and 90 degrees

Front 26

What is the normal T wave axis?

Back 26

Variable, but within 50 to 60 degrees of the QRS axis

Front 27

What is a simple way to define an axis precisely.

Back 27

Look for the most biphasic limb lead; the axis must be perpendicular to it.

Front 28

True or False:
Biphasic waves sometimes appear flat on EKG.

Back 28

True.

Front 29

True or False:
The concept of axis deviation is most successfully applied to ventricular hypertrophy.

Back 29

True

Front 30

In which direction would you expect the axis to deviate with left ventricular hypertrophy?

Back 30

leftward

Front 31

What is the duration of a normal P wave?

Back 31

less than 0.12 seconds

Front 32

What is the largest deflection of a normal P wave?

Back 32

not to exceed 2.5 mm

Front 33

Which two leads contain virtually all of the information needed to assess atrial enlargement?

Back 33

Leads II and V1

Front 34

Why is Lead II useful for assessing atrial enlargement?

Back 34

It is nealy parallel to the flow of current through the atria and records the largest deflection.

Front 35

Why is Lead V1 useful for assessing atrial enlargement?

Back 35

Because it is perpendicular to atrial depolarization, it produces a biphasic wave that separates the right and left atrial components.

Front 36

True or False:
With right atrial enlargement, the amplitude of the first portion of the P-wave increases.

Back 36

True.

Front 37

True or False:
In atrial enlargement, the tallest P-wave may occasionally appear in AVF or Lead III instead of Lead II.

Back 37

True.
This is possible in cases where right atrial enlargement shifts the P-wave axis to the right.

Front 38

What diagnosis is made in the presence of P-waves with an amplitude exceeding 2.5 mm in the inferior leads, II, III, and AVF?

Back 38

right atrial enlargement

Front 39

What diagnosis is made in the presence of a P wave that drops at least 1mm below the isoelectric line on V1?

Back 39

left atrial enlargement

Front 40

True or False:
The second portion of the P wave may increase in amplitude with right atrial enlargement.

Back 40

False.
An increase in amplitude of the second portion of the P wave would indicate LEFT atrial enlargement.

Front 41

What is usually the most prominent P wave change in cases of left atrial enlargement?

Back 41

an increase in duration

Front 42

Why does left (but not right) atrial enlargement increase the duration of the P wave.

Back 42

Any increase in the right atrial duration would be hidden by the left atrial portion of the P wave. Conversely, since the left atrial portion of the P wave is terminal, any increase in left atrial duration would be visible.

Front 43

What myocardial event does increased P-wave duration reflect?

Back 43

prolonged depolarization

Front 44

True or False:
The diagnosis of left atrial enlargement requires that the terminal portion of the P wave should be at least one small block (0.04 secs) in width.

Back 44

True.

Front 45

What is the minimum width of the terminal portion of the P wave in order to make a diagnosis of left atrial enlargement?

Back 45

1 small block
(0.04 seconds)

Front 46

Name the three signs that characterize right atrial enlargement.

Back 46

(1) P waves with an amplitute exceeding 2.5 mm in inferior leads

(2) No change in the duration of the P wave

(3) Possible right axis deviation of the P wave

Front 47

Name the three signs that characterize left atrial enlargement.

Back 47

(1) The amplitude of the terminal (negative) component of the P wave may be increased and must descend at least 1 mm below the isoelectric line on lead V1

(2) The duration of the P wave is increased, and the terminal (negative) portion of the P wave must be at least 1 small block (0.04 secs) in width

(3) No significant axis deviation is seen because the left atrium is normally electrically dominant

Front 48

True or False:
EKG evidence of atrial enlargement (especially left atrial enlargement) often has no pathologic correlate.

Back 48

True.
Interpretation of atrial enlargement on EKG must be tempered by knowledge of the clinical setting.

Front 49

True or False:
The diagnosis of ventricular hypertrophy is made by viewing V1 and V6 alone.

Back 49

False.
Thr diagnosis of ventricular hypertrophy requires a careful assessment of the QRS complex in many leads.

Front 50

What is the most common feature associated with right ventricular hypertrophy in the limb leads?

Back 50

right axis deviation

Front 51

According to many cardiologists, what degree of right axis deviation must be exceeded to make the diagnosis of right ventricular hypertrophy?

Back 51

100 degrees

Front 52

True or False:
In right ventricular hypertrophy, the QRS complex in lead I must be positive.

Back 52

False.
In right ventricular hypertrophy, since the axis will have shifted at least 100 degrees drifting away from Lead I, the QRS complex in Lead I must appear slightly more negative than positive.

Front 53

True or False:
An essential criterion for diagnosing right ventricular hypertrophy is a slightly negative QRS complex in Lead I.

Back 53

True.
Many cardiologists believe this to be the case.

Front 54

True or False:
The precordial leads are helpful in diagnosing right ventricular hypertrophy.

Back 54

True.

Front 55

What two simple precordial lead findings help to indentify right ventricular hypertrophy?

Back 55

V1: R wave larger than S wave

V6: S wave larger than R wave

Front 56

True or false:
R wave progression across precordial leads may reverse in right ventricular hypertrophy.

Back 56

True

Front 57

What are the two most common causes of right ventricular hypertrophy?

Back 57

pulmonary disease and
congenital heart disease

Front 58

True or False:
The diagnosis of left ventricular hypertrophy is more complicated than that of right ventricular hypertrophy.

Back 58

True.
Since the left ventrical is normally dominant anyway, enhanced levels of dominance are not always easy to pick out.

Front 59

True or False:
Left axis deviation beyond negative 15 degrees is often seen in left ventricular hypertrophy.

Back 59

True.
But this is not a very useful diagnostic feature.

Front 60

True or False:
There are myriads of criteria for identifying left ventricular hypertrophy.

Back 60

True

Front 61

True or False:
The central theme in identifying left ventricular hypertrophy is that there should be increased R wave amplitude in leads overlying the left ventricle and increased S wave amplitude overlying the right ventricle.

Back 61

True

Front 62

True or False:
In general, the precordial leads are more sensitive than the limb leads for the diagnosis of left ventricular hypertrophy.

Back 62

True

Front 63

List the four most useful precordial lead criteria used to diagnose left ventricular hypertrophy. (The more criteria that are positive, the greater the likelihood of ventricular hypertrophy).

Back 63

(1) R wave amplitude in V5 or V6 plus S wave amplitude in V1 or V2 exceeds 35mm

(2) R wave amplitude in V5 exceeds 26mm

(3) R wave amplitude in V6 exceeds 18 mm

(4) R wave amplitude in V6 exceeds R wave amplitude in V5

Front 64

The sum of the R wave amplitude in V5 and the S wave amplitude in V1 exceed 35 mm. What do you suspect?

Back 64

left ventricular hypertrophy

Front 65

When adding together the R and S waves in V6 and V2, the total exceeds 35 mm. What is the diagnosis?

Back 65

left ventricular hypertrophy

Front 66

If the R wave amplitude in V5 is 25 mm, what can you say about the left ventricle.

Back 66

It is probably normal.

Front 67

If the R wave amplitude in V5 is about 27 mm, what can you say about the left ventricle?

Back 67

It may be hypertrophied.

Front 68

Left vertricular hypertrophy may exist if the R wave in V6 exceeds what amplitude?

Back 68

18 mm

Front 69

Left ventricular hypertrophy may exist if the R wave in V5 exceeds what amplitude?

Back 69

26 mm

Front 70

What if the R wave amplitude in V6 is less than the R wave amplitude in V5?

Back 70

this is normal

Front 71

What if the R wave amplitude in V6 exceeds the R wave amplitude in V5?

Back 71

There is possible left ventricular hypertrophy.

Front 72

Ventricular hypertrophy may be present if the R wave amplitude in V5 is less than the R wave amplitude in which lead?

Back 72

V6

Front 73

Left ventricular hypertrophy may exist if the R wave in V5 or V6 plus the S wave in V1 or V2 exceeds what combined amplitude?

Back 73

35 mm

Front 74

True or False:
Precordial lead findings are often of little value in individuals younger than 35 years of age.

Back 74

True.
This is because the voltage and amplitude is generally increased due to a relatively thin chest wall.

Front 75

What effect does a thin chest wall, especially in those under the age of 35, have on EKG?

Back 75

Voltage and amplitude are increased in many cases.

Front 76

In diagnosing left ventricular hypertrophy, what are the four most useful criteria in limb lead assessment?

Back 76

(1) R wave amplitude in lead AVL exceeds 13 mm.

(2) R wave amplitude in lead AVF exceeds 21 mm.

(3) R wave amplitude in Lead I exceeds 14 mm.

(4) R wave amplitude in Lead I plus the S wave amplitude in Lead III exceeds 25 mm.

Front 77

You would suspect left ventricular hypertrophy if AVL shows an R wave that exceeds what amplitude?

Back 77

13 mm

Front 78

You would suspect left ventricular hypertrophy if AVF shows an R wave that exceeds what amplitude?

Back 78

21 mm

Front 79

You would suspect left ventricular hypertrophy if Lead I shows an R wave that exceeds what amplitude?

Back 79

14 mm

Front 80

You would suspect left ventricular hypertrophy if the combined amplitude of the Lead I R-wave and the Lead III S-wave exceeds what value?

Back 80

25 mm

Front 81

True or False:
Both right and left ventricular hypertrophy may slightly prolong the QRS complex.

Back 81

True.
But rarely beyond 0.1 second.

Front 82

What happens when both the right and left ventricles are hypertrophied?

Back 82

The effects of the usually dominant left ventricle obscure those of the right ventricle, in most cases.

Front 83

Phenomenon that may occur with ventricular hypertrophy in which the ST segment and T wave are dramatically altered.

Back 83

secondary repolarization abnormalities

Front 84

Secondary abnormalities generally include what characteristics?

Back 84

Down-sloping ST segment depression

T wave inversion

Front 85

What is the cause of secondary repolarization abnormalities.

Back 85

Theories range from hypoperfusion to overlapping depolarization and repolarization forces, but no one knows for sure.

Front 86

Until recently, what term was used to describe secondary repolarization abonormalities?

Back 86

Until recently, these changes were referred to as "strain." However, the implication that the changes necessarily reflect strained tissue has proven overly simplistic, so the term has been largely discarded.

Front 87

Name the phenomenon in which a depressed ST segment and inverted T wave blend to form a single, asymmetric wave.

Back 87

secondary repolarization abnormalities

Front 88

Phenomenon involving the ST interval in which the downward slope is gradual and the upward slope is abrupt.

Back 88

secondary repolarization abnormalities

Front 89

True or False:
Repolarization abnormalities are not at all uncommon.

Back 89

True.

Front 90

In which leads are repolarization abnormalities most evident?

Back 90

In those with tall R waves.

Front 91

In which leads are repolarization abnormalities associated with the right ventricle likely to be most clearly seen?

Back 91

V1 and V2

Front 92

In which leads are repolarization abnormalities associated with the left ventricle likely to be most clearly seen?

Back 92

V5, V6, AVL, and Lead I

(leads with the tallest R waves)

Front 93

True or False:
Right ventricular repolarization abnormalities are more common than left ventricular abnormalities.

Back 93

False.
Left ventricular repolarization abnormalities are far more common.

Front 94

True or False:
Repolarization abnormalities usually accompany sever hypertrophy and may even herald the onset of ventricular dilation.

Back 94

True.

Front 95

Summarily, what are the two most useful criteria for identifying right ventricular hypertrophy?

Back 95

(1) Right axis deviation exceeding 100 degrees

(2) R larger than S in V1; S larger than R in V6
(reverse of normal r-wave progression)

Front 96

Summarily, what are the two most useful criteria for identifying left ventricular hypertrophy?

Back 96

(1) R in V5 or V6 plus S in V1 or V2 exceed 35 mm

(2) R in AVL exceeds 13 mm