Term
| What is the normal mean electrical axis? |
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Definition
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Term
| What 3 things may happen when a chamber hypertrophies or enlarges? |
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Definition
1. EKG wave may increase in duration (widen)
2. EKG wave may increase in amplitude
3. There may be a shift of the electrical axis |
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Term
| What kind of overload is dilation due to? |
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Definition
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Term
| What kind of overload is hypertrophy due to? |
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Definition
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Term
| How do you determine if the QRS axis is normal? |
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Definition
| If QRS is + in Lead I and aVF |
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Term
| If lead I is +, what is the possible range for the QRS axis? |
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Definition
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Term
| If aVF is +, what is the possible range for the QRS axis? |
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Definition
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Term
| What are the 2 ways to assess the QRS axis in limb leads? |
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Definition
1. Look for the tallest wave. If 2 waves are equally high - the mean QRS axis is between the 2.
2. Look for a biphasic wave - QRS axis is 90 degrees perpendicular to that lead. |
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Term
| Name the anterior leads, left lateral leads, inferior leads, and right ventricular leads. |
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Definition
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Leads
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Group
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V2, V3, V4
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Anterior
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I, aVL, V5, V6
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Left lateral
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II, III, aVF
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Inferior
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aVR, V1
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Right ventricular
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Term
| Define right axis deviation. |
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Definition
QRS axis between 90 and 180.
Lead I is -
aVF is + |
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Term
| Define left axis deviation. |
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Definition
QRS axis lies between 0 and -90.
Lead I is +
aVF is - |
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Term
| What is the axis called if it is between -90 and 180? |
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Definition
Extreme right axis deviation
Lead I and aVF are negative |
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Term
T/F
Axis is defined in the frontal plane only. |
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Definition
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Term
| What are the angles of the frontal leads? |
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Definition
Lead I 0
Lead II +60
Lead III +120
Lead aVL -30
Lead aVR -150
Lead aVF 90 |
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Term
T/F
Right ventricular hypertrophy is more common than left ventricular hypertrophy. |
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Definition
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Term
| What type of axis deviation results from left ventricular hypertrophy? |
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Definition
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Term
| When might right ventricular hypertrophy occur? |
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Definition
In patients with COPD sufficiently severe to cause pulmonary artery hypertension
Or in patients with uncorrected congenital hearts disease associated with profound volume or pressure overload of the right ventricle |
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Term
| What 3 things can happen to a wave on the EKG with enlargement or hypertrophy? |
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Definition
1. The wave can increase in duration.
2. The wave can increase in amplitude.
3. The electrical axis of the wave can deviate from normal. |
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Term
| How long is the normal P wave in duration? |
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Definition
| 0.12 sec (between 1/2 and 1 big box) |
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Term
| What is the largest amplitude of a normal P wave? |
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Definition
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Term
| What is the value of 1 small box vertically? 1 big box? |
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Definition
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Term
| What is the value of 1 small box horizontally? 1 big box? |
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Definition
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Term
| Draw the frontal leads on the heart with the correct angles. |
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Definition
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Term
T/F
The first half of the P wave represents left atrial depolarization. |
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Definition
| False - it represents right atrial depolarization |
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Term
| What leads do you look at to assess atrial enlargement? |
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Definition
Leads II and V1.
Lead II is nearly parallel to the P wave vector and is therefore the largest positive deflection.
V1 is perpendicular and therefore is biphasic so as to separate right and left atrial components. |
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Term
| How does the P wave change with right atrial enlargement? |
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Definition
| The amplitude of the first portion of the P wave increases, but duration (width) does not change |
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Term
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Definition
The classic picture of r. atrial enlargement - increased amplitude of the P wave in lead II and increased amplitude of the first half of the P wave in lead V1
So called because it is often caused by severe lung disease |
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Term
| How is right atrial enlargement diagnosed? |
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Definition
| By the presence of P waves with an amplitude > 2.5 mm in the inferior leads II, III, and aVF. |
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Term
| What is required for the diagnosis of left atrial enlargement? |
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Definition
terminal portion of the P wave should drop more than 1 mm below the isoelectric line in lead V1
And the P wave should also be at least 0.04 secs in duration (1 small block) |
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Term
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Definition
Picture of left atrial enlargment, increased amplitude of the second half of the P wave in lead II and in lead V1, also increased duration.
So called because mitral valve disease is a common cause of left atrial enlargement |
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Term
| Which leads do you examine to diagnose atrial enlargment? |
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Definition
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Term
| What 3 things characterize right atrial enlargment? |
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Definition
1. P waves with amplitude > 2.5 mm in inferior leads
2. No change in duration of P wave
3. Possible right axis deviation of P wave |
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Term
| What 3 things characterize left atrial enlargement? |
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Definition
1. Amplitude of negative component of P wave may be increased and must descend at least 1 mm below isoelectric line in lead V1.
2. The duration of the P wave is increased and the terminal portion of the P wave must be at least 0.04 secs in duration (1 small block).
3. No significant axis deviation because left atrium is normally electrically dominant |
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Term
T/F
Abnormalities of the P wave always suggest atrial enlargement or hypertrophy. |
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Definition
| False - they can suggest that the heart rhythm is arising from somewhere other than the sinus node. Also, often has no pathological correlate and may even reflect some nonspecific conduction abnormality. |
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Term
T/F
The diagnosis of ventricular hypertrophy requires assessment of the QRS complex in many leads. |
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Definition
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Term
| What is the most common feature associated with right ventricular hypertrophy that is seen in the limb leads? |
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Definition
| right axis deviation between 90 and 180 |
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Term
T/F
For the diagnosis of right ventricular hypertrophy, the QRS complex should be more negative than positive in lead I. |
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Definition
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Term
T/F
When evaluating for right ventricular hypertrophy, you should look at the precordial leads. |
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Definition
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Term
| In right ventricular hypertrophy, what do the R and S waves look like in leads V1 and V6? |
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Definition
Lead V1 - R wave > S wave
Lead V6 - S wave > R wave |
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Term
| What are the most common causes of right ventricular hypertrophy? |
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Definition
| pulmonary disease and congenital heart disease |
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Term
T/F
The diagnosis of R ventricular hypertrophy is more complicated than for L ventricular hypertrophy. |
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Definition
| False - L VH is more complicated to diagnose. |
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Term
| What forms the basis for the diagnosis of left ventricular hypertrophy? |
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Definition
increased R wave amplitude in those leads overlying the left ventricle
increased S wave amplitude in those leads overlying the right ventricle |
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Term
| Which leads are more sensitive for the diagnosis of L ventricular hypertrophy? |
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Definition
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Term
| Name the 4 most useful criteria in the precordial leads for diagnosis of L ventricular hypertrophy. |
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Definition
1. R amplitude in V5 or V6 + the S amplitude in V1 or V2 exceeds 35 mm
2. R amplitude in V5 exceeds 26 mm
3. R amplitude in V6 exceeds 18 mm
4. R amplitude in V6 exceeds the R amplitude in V5
useful in those > 35 years |
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Term
| Name the 4 most useful criteria in the limb leads for diagnosis of L ventricular hypertrophy. |
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Definition
1. R amplitude in aVL exceeds 13 mm
2. R amplitude in aVF exceeds 21 mm
3. R amplitude in lead I exceeds 14 mm
4. R amplitude in lead I + S amplitude in lead III exceeds 25 mm |
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Term
| What are the leading causes of L ventricular hypertrophy? |
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Definition
| systemic hypertension and valvular disease |
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Term
T/F
Both R and L ventricular hypertrophy may prolong the QRS complex but rarely beyond 0.1 sec. |
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Definition
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Term
| What are secondary repolarization abnormalities? What are these also called? |
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Definition
1. Down sloping ST segment depression
2. T wave inversion
Strain |
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Term
T/F
Repolarization abnormalities are most evident in those leads with tall R waves. |
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Definition
True
R vent. repolarization will be seen in leads V1 and V2
L vent. repolarization will be seen in Leads I, aVL, V5 and V6 |
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Term
| When are repolarization abnormalities most likely to be seen? |
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Definition
with severe hypertrophy
may herald the onset of ventricular dilation |
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Term
| What are the 2 main characteristics of R ventricular hypertrophy? |
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Definition
1. Right axis deviation, with QRS axis exceeding 100
2. R wave > S wave in V1
S wave > R wave in V6 |
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Term
| What are the 2 main characteristics of L ventricular hypertrophy? |
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Definition
1. R in V5 or V6 + S in V1 or V2 exceeds 35 mm
2. R in aVL exceeds 13 mm
Also see T wave inversion and down-sloping ST segement. Left axis deviation exceeding -15 present too. |
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Term
| How sensitive and specific is L ventricular hypertrophy EKG criteria? |
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Definition
| It is not very sensitive (only shows up in 50% of patients), but it is pretty specific (if it's there, 90% have hypertrophy) |
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