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96 Cards in this Set

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An increase in muscle mass
hypertrophy
What is the cause of most heart chamber hypertrophy?
pressure overload
(pumping against increased resistance)
What is another term for dilation of a particular heart chamber?
enlargement
What is typically the cause of heart chamber enlargement?
volume overload
(increased amount of blood in chamber)
True or False:
EKG is very efficient at distinguishing between hypertrophy and enlargement.
False
True or False:
On the EKG, it is common to speak of "atrial hypertrophy."
False.
It is traditional to speak of "atrial enlargement" within the context of EKG readings.
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.
True
What is another commonly used term for atrial enlargement on EKG.
atrial abnormalities
Name the three things that can happen to a wave on EKG when a chamber hypertrophies or enlarges.
(1) Increase in duration
(2) Increase in amplitude
(3) Electrical axis shift
What term describes the average vector of all instantaneous vectors recorded by EKG?
the mean vector
What term refers to the direction of the mean vector on EKG?
the mean electrical axis
On which plane of the EKG is axis defined?
frontal plane
True or False:
The horizontal plane defines the axis.
False.
Axis is defined on the frontal plane only.
What is the range of the normal QRS axis?
90 degrees to 0 degrees

(or 90 to negative 30,
according to most cardiologists)
Which two leads are used to quickly determing whether the QRS axis on any EKG is normal?
Lead I and AVF
True or False:
Lead I and AVF negative deflections indicate a normal QRS axis.
False.
Positive deflections on Lead I and AVF are consistent with a normal axis.
True or False:
If the QRS complex is positive in leads I and AVF, the QRS axis MUST be normal.
True.
True or False:
If the QRS complex in either lead I or AVF is not predominantly positive, the QRS axis is not normal.
True.
If Lead I is negative and AVF is negative, define the axis.
extreme right axis deviation
If Lead I is negative and AVF is positive, define the axis.
right axis deviation
If Lead I is positive and AVF is negative, define the axis.
left axis deviation
If Lead I is positive and AVF is positive, define the axis.
normal axis
What kind of deflections would you expect on Lead I and AVF on a normal EKG?
predominantly positive
What is the normal P wave axis in adults?
between 0 and 70 degrees
What is the normal P wave axis in children?
between 0 and 90 degrees
What is the normal T wave axis?
Variable, but within 50 to 60 degrees of the QRS axis
What is a simple way to define an axis precisely.
Look for the most biphasic limb lead; the axis must be perpendicular to it.
True or False:
Biphasic waves sometimes appear flat on EKG.
True.
True or False:
The concept of axis deviation is most successfully applied to ventricular hypertrophy.
True
In which direction would you expect the axis to deviate with left ventricular hypertrophy?
leftward
What is the duration of a normal P wave?
less than 0.12 seconds
What is the largest deflection of a normal P wave?
not to exceed 2.5 mm
Which two leads contain virtually all of the information needed to assess atrial enlargement?
Leads II and V1
Why is Lead II useful for assessing atrial enlargement?
It is nealy parallel to the flow of current through the atria and records the largest deflection.
Why is Lead V1 useful for assessing atrial enlargement?
Because it is perpendicular to atrial depolarization, it produces a biphasic wave that separates the right and left atrial components.
True or False:
With right atrial enlargement, the amplitude of the first portion of the P-wave increases.
True.
True or False:
In atrial enlargement, the tallest P-wave may occasionally appear in AVF or Lead III instead of Lead II.
True.
This is possible in cases where right atrial enlargement shifts the P-wave axis to the right.
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?
right atrial enlargement
What diagnosis is made in the presence of a P wave that drops at least 1mm below the isoelectric line on V1?
left atrial enlargement
True or False:
The second portion of the P wave may increase in amplitude with right atrial enlargement.
False.
An increase in amplitude of the second portion of the P wave would indicate LEFT atrial enlargement.
What is usually the most prominent P wave change in cases of left atrial enlargement?
an increase in duration
Why does left (but not right) atrial enlargement increase the duration of the P wave.
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.
What myocardial event does increased P-wave duration reflect?
prolonged depolarization
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.
True.
What is the minimum width of the terminal portion of the P wave in order to make a diagnosis of left atrial enlargement?
1 small block
(0.04 seconds)
Name the three signs that characterize right atrial enlargement.
(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
Name the three signs that characterize left atrial enlargement.
(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
True or False:
EKG evidence of atrial enlargement (especially left atrial enlargement) often has no pathologic correlate.
True.
Interpretation of atrial enlargement on EKG must be tempered by knowledge of the clinical setting.
True or False:
The diagnosis of ventricular hypertrophy is made by viewing V1 and V6 alone.
False.
Thr diagnosis of ventricular hypertrophy requires a careful assessment of the QRS complex in many leads.
What is the most common feature associated with right ventricular hypertrophy in the limb leads?
right axis deviation
According to many cardiologists, what degree of right axis deviation must be exceeded to make the diagnosis of right ventricular hypertrophy?
100 degrees
True or False:
In right ventricular hypertrophy, the QRS complex in lead I must be positive.
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.
True or False:
An essential criterion for diagnosing right ventricular hypertrophy is a slightly negative QRS complex in Lead I.
True.
Many cardiologists believe this to be the case.
True or False:
The precordial leads are helpful in diagnosing right ventricular hypertrophy.
True.
What two simple precordial lead findings help to indentify right ventricular hypertrophy?
V1: R wave larger than S wave

V6: S wave larger than R wave
True or false:
R wave progression across precordial leads may reverse in right ventricular hypertrophy.
True
What are the two most common causes of right ventricular hypertrophy?
pulmonary disease and
congenital heart disease
True or False:
The diagnosis of left ventricular hypertrophy is more complicated than that of right ventricular hypertrophy.
True.
Since the left ventrical is normally dominant anyway, enhanced levels of dominance are not always easy to pick out.
True or False:
Left axis deviation beyond negative 15 degrees is often seen in left ventricular hypertrophy.
True.
But this is not a very useful diagnostic feature.
True or False:
There are myriads of criteria for identifying left ventricular hypertrophy.
True
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.
True
True or False:
In general, the precordial leads are more sensitive than the limb leads for the diagnosis of left ventricular hypertrophy.
True
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).
(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
The sum of the R wave amplitude in V5 and the S wave amplitude in V1 exceed 35 mm. What do you suspect?
left ventricular hypertrophy
When adding together the R and S waves in V6 and V2, the total exceeds 35 mm. What is the diagnosis?
left ventricular hypertrophy
If the R wave amplitude in V5 is 25 mm, what can you say about the left ventricle.
It is probably normal.
If the R wave amplitude in V5 is about 27 mm, what can you say about the left ventricle?
It may be hypertrophied.
Left vertricular hypertrophy may exist if the R wave in V6 exceeds what amplitude?
18 mm
Left ventricular hypertrophy may exist if the R wave in V5 exceeds what amplitude?
26 mm
What if the R wave amplitude in V6 is less than the R wave amplitude in V5?
this is normal
What if the R wave amplitude in V6 exceeds the R wave amplitude in V5?
There is possible left ventricular hypertrophy.
Ventricular hypertrophy may be present if the R wave amplitude in V5 is less than the R wave amplitude in which lead?
V6
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?
35 mm
True or False:
Precordial lead findings are often of little value in individuals younger than 35 years of age.
True.
This is because the voltage and amplitude is generally increased due to a relatively thin chest wall.
What effect does a thin chest wall, especially in those under the age of 35, have on EKG?
Voltage and amplitude are increased in many cases.
In diagnosing left ventricular hypertrophy, what are the four most useful criteria in limb lead assessment?
(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.
You would suspect left ventricular hypertrophy if AVL shows an R wave that exceeds what amplitude?
13 mm
You would suspect left ventricular hypertrophy if AVF shows an R wave that exceeds what amplitude?
21 mm
You would suspect left ventricular hypertrophy if Lead I shows an R wave that exceeds what amplitude?
14 mm
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?
25 mm
True or False:
Both right and left ventricular hypertrophy may slightly prolong the QRS complex.
True.
But rarely beyond 0.1 second.
What happens when both the right and left ventricles are hypertrophied?
The effects of the usually dominant left ventricle obscure those of the right ventricle, in most cases.
Phenomenon that may occur with ventricular hypertrophy in which the ST segment and T wave are dramatically altered.
secondary repolarization abnormalities
Secondary abnormalities generally include what characteristics?
Down-sloping ST segment depression

T wave inversion
What is the cause of secondary repolarization abnormalities.
Theories range from hypoperfusion to overlapping depolarization and repolarization forces, but no one knows for sure.
Until recently, what term was used to describe secondary repolarization abonormalities?
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.
Name the phenomenon in which a depressed ST segment and inverted T wave blend to form a single, asymmetric wave.
secondary repolarization abnormalities
Phenomenon involving the ST interval in which the downward slope is gradual and the upward slope is abrupt.
secondary repolarization abnormalities
True or False:
Repolarization abnormalities are not at all uncommon.
True.
In which leads are repolarization abnormalities most evident?
In those with tall R waves.
In which leads are repolarization abnormalities associated with the right ventricle likely to be most clearly seen?
V1 and V2
In which leads are repolarization abnormalities associated with the left ventricle likely to be most clearly seen?
V5, V6, AVL, and Lead I

(leads with the tallest R waves)
True or False:
Right ventricular repolarization abnormalities are more common than left ventricular abnormalities.
False.
Left ventricular repolarization abnormalities are far more common.
True or False:
Repolarization abnormalities usually accompany sever hypertrophy and may even herald the onset of ventricular dilation.
True.
Summarily, what are the two most useful criteria for identifying right ventricular hypertrophy?
(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)
Summarily, what are the two most useful criteria for identifying left ventricular hypertrophy?
(1) R in V5 or V6 plus S in V1 or V2 exceed 35 mm

(2) R in AVL exceeds 13 mm