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96 Cards in this Set
- Front
- Back
An increase in muscle mass
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hypertrophy
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What is the cause of most heart chamber hypertrophy?
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pressure overload
(pumping against increased resistance) |
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What is another term for dilation of a particular heart chamber?
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enlargement
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What is typically the cause of heart chamber enlargement?
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volume overload
(increased amount of blood in chamber) |
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True or False:
EKG is very efficient at distinguishing between hypertrophy and enlargement. |
False
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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. |
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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
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What is another commonly used term for atrial enlargement on EKG.
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atrial abnormalities
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Name the three things that can happen to a wave on EKG when a chamber hypertrophies or enlarges.
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(1) Increase in duration
(2) Increase in amplitude (3) Electrical axis shift |
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What term describes the average vector of all instantaneous vectors recorded by EKG?
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the mean vector
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What term refers to the direction of the mean vector on EKG?
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the mean electrical axis
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On which plane of the EKG is axis defined?
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frontal plane
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True or False:
The horizontal plane defines the axis. |
False.
Axis is defined on the frontal plane only. |
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What is the range of the normal QRS axis?
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90 degrees to 0 degrees
(or 90 to negative 30, according to most cardiologists) |
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Which two leads are used to quickly determing whether the QRS axis on any EKG is normal?
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Lead I and AVF
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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. |
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True or False:
If the QRS complex is positive in leads I and AVF, the QRS axis MUST be normal. |
True.
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True or False:
If the QRS complex in either lead I or AVF is not predominantly positive, the QRS axis is not normal. |
True.
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If Lead I is negative and AVF is negative, define the axis.
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extreme right axis deviation
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If Lead I is negative and AVF is positive, define the axis.
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right axis deviation
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If Lead I is positive and AVF is negative, define the axis.
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left axis deviation
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If Lead I is positive and AVF is positive, define the axis.
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normal axis
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What kind of deflections would you expect on Lead I and AVF on a normal EKG?
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predominantly positive
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What is the normal P wave axis in adults?
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between 0 and 70 degrees
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What is the normal P wave axis in children?
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between 0 and 90 degrees
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What is the normal T wave axis?
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Variable, but within 50 to 60 degrees of the QRS axis
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What is a simple way to define an axis precisely.
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Look for the most biphasic limb lead; the axis must be perpendicular to it.
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True or False:
Biphasic waves sometimes appear flat on EKG. |
True.
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True or False:
The concept of axis deviation is most successfully applied to ventricular hypertrophy. |
True
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In which direction would you expect the axis to deviate with left ventricular hypertrophy?
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leftward
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What is the duration of a normal P wave?
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less than 0.12 seconds
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What is the largest deflection of a normal P wave?
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not to exceed 2.5 mm
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Which two leads contain virtually all of the information needed to assess atrial enlargement?
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Leads II and V1
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Why is Lead II useful for assessing atrial enlargement?
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It is nealy parallel to the flow of current through the atria and records the largest deflection.
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Why is Lead V1 useful for assessing atrial enlargement?
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Because it is perpendicular to atrial depolarization, it produces a biphasic wave that separates the right and left atrial components.
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True or False:
With right atrial enlargement, the amplitude of the first portion of the P-wave increases. |
True.
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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. |
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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?
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right atrial enlargement
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What diagnosis is made in the presence of a P wave that drops at least 1mm below the isoelectric line on V1?
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left atrial enlargement
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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. |
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What is usually the most prominent P wave change in cases of left atrial enlargement?
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an increase in duration
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Why does left (but not right) atrial enlargement increase the duration of the P wave.
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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.
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What myocardial event does increased P-wave duration reflect?
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prolonged depolarization
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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.
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What is the minimum width of the terminal portion of the P wave in order to make a diagnosis of left atrial enlargement?
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1 small block
(0.04 seconds) |
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Name the three signs that characterize right atrial enlargement.
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(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 |
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Name the three signs that characterize left atrial enlargement.
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(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 |
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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. |
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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. |
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What is the most common feature associated with right ventricular hypertrophy in the limb leads?
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right axis deviation
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According to many cardiologists, what degree of right axis deviation must be exceeded to make the diagnosis of right ventricular hypertrophy?
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100 degrees
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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. |
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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. |
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True or False:
The precordial leads are helpful in diagnosing right ventricular hypertrophy. |
True.
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What two simple precordial lead findings help to indentify right ventricular hypertrophy?
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V1: R wave larger than S wave
V6: S wave larger than R wave |
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True or false:
R wave progression across precordial leads may reverse in right ventricular hypertrophy. |
True
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What are the two most common causes of right ventricular hypertrophy?
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pulmonary disease and
congenital heart disease |
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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. |
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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. |
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True or False:
There are myriads of criteria for identifying left ventricular hypertrophy. |
True
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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
|
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True or False:
In general, the precordial leads are more sensitive than the limb leads for the diagnosis of left ventricular hypertrophy. |
True
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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).
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(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 |
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The sum of the R wave amplitude in V5 and the S wave amplitude in V1 exceed 35 mm. What do you suspect?
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left ventricular hypertrophy
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When adding together the R and S waves in V6 and V2, the total exceeds 35 mm. What is the diagnosis?
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left ventricular hypertrophy
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If the R wave amplitude in V5 is 25 mm, what can you say about the left ventricle.
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It is probably normal.
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If the R wave amplitude in V5 is about 27 mm, what can you say about the left ventricle?
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It may be hypertrophied.
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Left vertricular hypertrophy may exist if the R wave in V6 exceeds what amplitude?
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18 mm
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Left ventricular hypertrophy may exist if the R wave in V5 exceeds what amplitude?
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26 mm
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What if the R wave amplitude in V6 is less than the R wave amplitude in V5?
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this is normal
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What if the R wave amplitude in V6 exceeds the R wave amplitude in V5?
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There is possible left ventricular hypertrophy.
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Ventricular hypertrophy may be present if the R wave amplitude in V5 is less than the R wave amplitude in which lead?
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V6
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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?
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35 mm
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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. |
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What effect does a thin chest wall, especially in those under the age of 35, have on EKG?
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Voltage and amplitude are increased in many cases.
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In diagnosing left ventricular hypertrophy, what are the four most useful criteria in limb lead assessment?
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(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. |
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You would suspect left ventricular hypertrophy if AVL shows an R wave that exceeds what amplitude?
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13 mm
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You would suspect left ventricular hypertrophy if AVF shows an R wave that exceeds what amplitude?
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21 mm
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You would suspect left ventricular hypertrophy if Lead I shows an R wave that exceeds what amplitude?
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14 mm
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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?
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25 mm
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True or False:
Both right and left ventricular hypertrophy may slightly prolong the QRS complex. |
True.
But rarely beyond 0.1 second. |
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What happens when both the right and left ventricles are hypertrophied?
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The effects of the usually dominant left ventricle obscure those of the right ventricle, in most cases.
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Phenomenon that may occur with ventricular hypertrophy in which the ST segment and T wave are dramatically altered.
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secondary repolarization abnormalities
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Secondary abnormalities generally include what characteristics?
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Down-sloping ST segment depression
T wave inversion |
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What is the cause of secondary repolarization abnormalities.
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Theories range from hypoperfusion to overlapping depolarization and repolarization forces, but no one knows for sure.
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Until recently, what term was used to describe secondary repolarization abonormalities?
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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.
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Name the phenomenon in which a depressed ST segment and inverted T wave blend to form a single, asymmetric wave.
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secondary repolarization abnormalities
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Phenomenon involving the ST interval in which the downward slope is gradual and the upward slope is abrupt.
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secondary repolarization abnormalities
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True or False:
Repolarization abnormalities are not at all uncommon. |
True.
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In which leads are repolarization abnormalities most evident?
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In those with tall R waves.
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In which leads are repolarization abnormalities associated with the right ventricle likely to be most clearly seen?
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V1 and V2
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In which leads are repolarization abnormalities associated with the left ventricle likely to be most clearly seen?
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V5, V6, AVL, and Lead I
(leads with the tallest R waves) |
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True or False:
Right ventricular repolarization abnormalities are more common than left ventricular abnormalities. |
False.
Left ventricular repolarization abnormalities are far more common. |
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True or False:
Repolarization abnormalities usually accompany sever hypertrophy and may even herald the onset of ventricular dilation. |
True.
|
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Summarily, what are the two most useful criteria for identifying right ventricular hypertrophy?
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(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) |
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Summarily, what are the two most useful criteria for identifying left ventricular hypertrophy?
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(1) R in V5 or V6 plus S in V1 or V2 exceed 35 mm
(2) R in AVL exceeds 13 mm |