ECG Interpretation Flashcards

(46 cards)

1
Q

If the magnitude of the upward and downward deflections are equal, this is known as isoelectric and indicates that the depolarization wave is moving

A

Perpendicular to the lead

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2
Q

The 6 limb leads (Inferior: II, III, and aVF, left lateral I and aVL, and right lateral aVR) tell us about the

A

Frontal plane of the heart

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3
Q

What does the PR segment show?

A

Atrial depolarization and AV node delay

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4
Q

How do we determine electrical axis of the heart?

A

Determine QRS voltages from leads I, II, and aVF

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5
Q

The average cardiac electrical axis approximates 50-60 degrees and falls somewhere between 0 and 90 degrees. Both leads I and aVF are predominantly

A

Positive

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6
Q

Leads I and II are positive and lead aVF is negative for a

A

Normal variant of 0-30 degrees

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7
Q

If

  1. ) Lead I is negative
  2. ) Lead II is isoelectric
  3. ) Lead aVF is positive

We have an axis of

A

Greater than 100 degrees and RIGHT axis deviation (RAD)

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8
Q

If

  1. ) Lead I is positive
  2. ) Lead II is negative
  3. ) Lead aVF is negative

We have an axis between

A

-30 and -90 degrees and a LEFT axis deviation (LAD)

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9
Q

On an ECG, one LARGE horizontal box equals

A

0.20 seconds

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10
Q

In an ECG, each SMALL horizontal box equals

A

0.04 seconds

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11
Q

How do we calculate beats per minute?

A

Look from R to R and do 300/number of large boxes

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12
Q

To calculate BPM from small boxes, do

A

Number of small boxes x 0.04

THEN

60 seconds / answer

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13
Q

Sinus brachycardia is a rate

A

Below 60 BPM

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14
Q

Sinus Tachycardia is a rate

A

Above 100 BPM

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15
Q

Refers to the time between R-R intervals

A

Rythym

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16
Q

During sinus rhythm, the time between R-R intervals is consistent during a given

A

Rate

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17
Q

Means that R-R intervals are not consistent

A

Irregular rhythm

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18
Q

How do we determine the rate for a slow irregular rythm?

A

Count the number of R peaks within 30 large boxes and multiply by 10

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19
Q

A normal PR interval is between

A

0.12 - 0.20 seconds

20
Q

How do we determine PR interval?

A

For the LONGEST PR seen, count number of little boxes between beginninng of P wave and first deflection of QRS

21
Q

Normal QRS intervals are

A

Less than 0.12 seconds

22
Q

Increased QRS intervals are

A

Greater than or equal to 0.12 seconds

23
Q

How do we calculate corrected QT interval?

A

QT interval / square root of preceding R-R interval

24
Q

What is a normal corrected QT interval?

A

0.35-0.43 seconds

25
Normally isoelectric with the other segments. Elevation or depression an indicate a pathological process such as myocardial injury or ischemia
ST segment
26
The time when the myocardium is electrically silent -isoelectric line of ECG
TP interval
27
Leads I and aVF are equally positive than
Axis is midway between 0 and 90 degrees (normal)
28
If ledds I and aVF are both positive but Lead I is MORE positive than aVF than
Axis is oriented more towards 0 (20 degrees to 40 degrees) -The normal variant
29
If lead I is positive and lead aVF is almost isoelectric than
The axis is approaching 0 -still normal
30
When lead I is positive and lead aVF is negative than
The axis is oreiented negatively past 0 -Left axis deviation (-30)
31
If lead I is negative and lead aVF is positive than
Right axis deviation
32
If both leads I and aVF are negative than we have an
Intermediate axis (-135)
33
If the QRS axis in leads I and II are positive than we have a
Normal axis
34
When interpreting P waves use leads
II and V1
35
If one half of the P wave is larger than the other, than we see
Atrial enlargement
36
Most common cause for left atrial enlargement?
Chronic hypertension or aortic stenosis
37
What is the criteria for classifying SINUS rythm
P precedes QRS and ratio is 1:1
38
What are some other things to look at on ECG?
1. ) P wave for atrial enlargement (II and V1) 2. ) ST elevation or depression 3. ) Be able to localize an MI 4. ) Inverted T waves in leads I, II, III
39
For rythm, don’t forget to check the
Rythm strip
40
In a normal heart, P and T waves should be positive in leads
I and II
41
Biphasic P waves are normal in the
Precordial leads
42
Atrial enlargement is best seen in Leads
II and V1
43
What is the criteria for A-fib?
1. ) Irregularly irregular rythm | 2. ) Absence of discernible P waves
44
Prolonged PR signifies
Primary Heart Block
45
Multiple P waves suggests
Secondary Heart Block
46
In order, what 5 things do you calculate on ECG?
1. ) Rate and rythm 2. ) PR interval 3. ) QRS interval 4. ) QT interval (and QTc for brachycardia and tachycardia) 5. ) QRS axis