Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

Internal Medicine > JH IM Board Review - Electrocardiogram Review I > Flashcards

JH IM Board Review - Electrocardiogram Review I Flashcards

1
Q

5 Fundamental features to assess when reading an electrocardiogram:

A
  1. Rate (beats per minute).
  2. Rhythm.
  3. Axis.
  4. Intervals.
  5. Waveforms.
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

Rate (beats per minute):

A
  1. Normal is 60 to 100 beats/min.
  2. Estimate rate by dividing 300 by the RR interval (as measured by number of large boxes (0.2sec) from R to R.
  3. Measure the RR interval to nearest 0.01sec and divide into 60 to calculate the rate more accurately (eg 60/0.4 = 150).
  4. For irregular rhythms, count the number of QRS complexes in 5, 6, 10, 20sec and multiply by the correct integer to get beats per minute.
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

For example, a standard ECG printout displays 10sec of data, so if there is a total of 25 QRS complexes …?

A

Multiply 25 x 6 = 150 beats/min.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

Rhythm - Basic questions:

A
  1. Too fast or too slow?
  2. Regular or irregular?
  3. Ventricular or supraventricular?
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

Axis - By convention, normal axis is …?

A

-30 to +90 degrees.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

Determine axis quadrant by evaluating …?

A

Positive or negative deflection of the QRS complex in leads I and aVF.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

Suggested method for axis determination:

A
  1. Examine lead I (0 degrees) and lead aVF (90 degrees).

2. Axis is normal if both leads are in the NET POSITIVE AREA (ie R-wave > Q + S-wave area).

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

If QRS area is negative in lead aVF, examine lead II:

A
  1. If QRS area is POSITIVE in LEAD II (ie R wave area > Q + S wave area) ==> Axis remains normal (between 0 and 30 degrees).
  2. If QRS area is NEGATIVE in LEAD II, then left-axis deviation is present (area between -30 and -90 degrees).
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

If QRS area is NEGATIVE in lead I, and POSITIVE in lead aVF, then …?

A

RIGHT-AXIS DEVIATION is present (area between +90 and 180 degrees).

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

If QRS area is NEGATIVE in leads I and aVF, then …?

A

Extreme axis deviation is present (-90 to 180 degrees or 180 to +270 degrees).

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

Intervals - PR:

A

Normal is 0.12-0.20sec.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

Intervals - QRS:

A

Normal is LESS THAN 0.12sec.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

Intervals - QT interval varies with HR:

A
  1. Inversely proportional to HR.
  2. Roughly, prolonged QT is present when the QT interval is MORE THAN THE HALF the preceding RR interval (less reliable at faster heart rates).
  3. Corrected QT adjusts for HR ==> QT divided by the square root of RR interval.

==> NORMAL QTc is 0.36-0.41sec.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

Waveforms - Pathologic Q waves (indicative of previous transmural STEMI):

A

To be considered pathologic, Q waves must be 1 small box wide and 1 small box deep.
(1 small box in width equals 0.04sec at 25mm/s)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

Waveforms - Septal Q waves:

A

ANY SIZE Q waves are abnormal in leads V1-V3.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

Waveforms - Anterior Q waves

A

Pathologic Q waves in leads V2-V4.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

Waveforms - Lateral pathologic Q waves:

A

Pathologic Q waves in leads I, aVL, V5-V6.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

Waveforms - Apical Q waves:

A

Pathologic Q waves in leads V5-V6.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

Waveforms - Inferior Q waves:

A

Pathologic Q waves in leads II, III, and aVF.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

Waveforms - Posterior Q waves:

A

No Q waves are present with this type of MI.

==> Prominent R waves in leads V1 and V2.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

Waveforms - ST segments:

A

Elevation or depression >1mm.

22
Q

Waveforms - T wave abnormalities:

A

Inversion or pseudonormalization.

23
Q

Selected EKG abnormalities - AV block 1st degree:

A
  1. PR interval greater than 0.2sec.
  2. By itself, of no clinical consequence (can be EXACERBATED with AV nodal blocking agents, such as verapamil or digoxin).
24
Q

Selected EKG abnormalities - AV block 2nd degree - Mobitz I (Wenkenbach block):

A
  1. Gradually increasing PR interval until a P wave is not followed by a QRS complex.
  2. Usually not clinically significant, but caution needed if administering AV nodal blocking agents.
25
Q

AV block 2nd degree - Mobitz II:

A
  1. Occasional dropped QRS complexes with no changes in PR interval for conducted beats ==> Higher degree of block, where oly a fraction of the P waves are followed by QRS complexes (eg 3:1).
  2. Usually caused by disease of the His-Purkinje system rather than the AV node itself.
  3. Worrisome conduction pattern, often progressing to complete heart block (requiring pacemaker therapy).
26
Q

AV block 3rd degree:

A
  1. Complete heart block.
  2. AV dissociation, where the PP and the RR intervals are different and the P waves are NOT responsible for subsequent QRS complexes.
  3. Usually symptomatic and requires pacemaker therapy.
27
Q

AV block 3rd degree - QRS complexes are usually …?

A

At a slow rate (“escape”), arising from INTRINSIC DEPOLARIZATION of the AV node (approx. 45-55 beats/min and with a NARROW [<0.12sec] QRS complex)

or the ventricle (approx. 35-45 beats/min and with a WIDE [>0.12sec] QRS complex.

28
Q

Low voltage - Definition:

A
  1. No R or S wave in limb leads greater than 5mm.

2. No R or S wave in precordial leads greater than 10mm.

29
Q

Low voltage - Causes:

A
  1. Obesity.
  2. COPD (incr. thorax size).
  3. Pericardial effusions or less commonly pleural effusions.
  4. Hypothyroidism.
  5. Addison.
  6. Infiltrative diseases (eg amyloidosis, hemochromatosis, sarcoidosis).
  7. Diffuse myocardial infarctions.
30
Q

LV hyperthrophy (LVH)- ECG:

A

NOT sensitive or specific for suggesting LVH (echo is the gold standard).

==> Many different ECG criteria exist for suggesting LVH.

31
Q

LVH - Suggested method:

A

Increased QRS voltage + evidence of “Strain”, left-axis deviation, or left atrial abnormality.

32
Q

Increased QRS voltage, as evidenced by one of the following:

A
  1. R or S wave greater than 20mm in any limb lead.
  2. S wave in leads V1-V3 or R wave in leads V4-V6 greater than 30mm.
  3. R wave in lead V5 + S wave in lead V1 greater than 35mm.
  4. R wave in lead aVL of 11mm or more.
  5. R wave in aVL + S wave in lead V3 of 28mm or more (men) or 20mm or more (women).
33
Q

“Strain” pattern:

A

ST-T changes (usually downward-sloping ST depression and T-wave inversion or biphasic T waves).

34
Q

Left atrial abnormality:

A

P wave greater than 0.12sec (in lead II) OR net negative P wave in lead V1 (negative amplitude >0.1mV).

35
Q

LVH - Causes:

A
  1. HTN.
  2. AV disease.
  3. Mitral insufficiency.
  4. HCM or DCM.
36
Q

Wide QRS complex - Definition:

A

QRS complex 0.12sec or more.

37
Q

Wide QRS complex - Potential causes:

A
  1. BBB.
  2. Ventricular rhythm.
  3. Hyperkalemia.
  4. WPW syndrome.
38
Q

BBB - Causes:

A
  1. Myocardial infarction.
  2. Infiltrative diseases (eg amyloidosis, hemochromatosis, sarcoidosis).
  3. Conduction system degeneration.
39
Q

ST-segment elevation abnormalities - Consider MI if:

A
  1. Located regionally (ie anterior [V2-V4], inferior [II, III, aVF], or lateral [V4-V6]).
  2. ST-segment is convexed upward (sharp angle of takeoff from QRS complex) or horizontal.
40
Q

ST-segment elevation abnormalities - Other causes include:

A
  1. EARLY REPOLARIZATION ==> typically diffuse concave upward ST-segment elevation.
  2. VENTRICULAR ANEURYSM ==> Acute, sharp-angled ST-segment elevation persisting after an ST-segment elevation MI.
  3. PERICARDITIS ==> Diffuse ST-segment elevation and concave upward (smooth, curved takeoff from QRS complex) (also associated with PR segment depression).
41
Q

Early repolarization is typically considered benign, BUT …?

A

Recent research suggests that it may be associated with SLIGHTLY INCREASED RISK OF EARLY CARDIAC DEATH, particularly if present in the inferior leads (II, III, and aVF.

42
Q

RBBB - Description:

A

Terminal S in I + V6

AND

rSR’ or tall R in V1.

43
Q

LBBB - Description:

A

Tall broad R in I + V6

AND

QS or rS in V1.

44
Q

Bifascicular block - Description:

A

RBBB + Left-axis deviation beyond -30 degrees.

OR

RBBB + Right axis deviation at least +120 degrees.

OR

LBBB.

45
Q

Trifascicular block - Description:

A

Bifascicular block (at right, LBBB) + Prolonged PR interval.

46
Q

Osborn waves:

A
  1. Positive deflection off declining shoulder of R wave.
  2. Gives a “notched” appearance to the R wave.
  3. Often seen with hypothermia.
47
Q

ECG findings associated with PE:

A
  1. MC ==> Sinus tachycardia.
  2. T wave inversions in inferior and precordial leads.
  3. Deep S wave in I (right-axis deviation) with a Q-wave and T-wave inversion in III (S1Q3T3).
48
Q

Electrical alternans:

A
  1. Alternating amplitude or direction of QRS complexes.

2. Associated with pericardial effusion caused by to-and-fro heart motion swinging in a fluid-filled pericardial sac.

49
Q

Inverted T waves - Potential causes (besides nonspecific):

A
  1. Intracranial hemorrhage or stroke ==> Classically associated with deep T-wave inversions and prolonged QT interval.
  2. Ischemia.
  3. Metabolic disorders.
  4. Stress cardiomyopathy (“broken heart syndrome”) ==> Acute, temporary, often profound cardiomyopathy frequently following sudden fear or surprise.
50
Q

Prolonged QT interval:

A

Associated with Torsades de pointes and sudden death.
Causes:

  1. Genetic.
  2. Metabolic (HYPOkalemia, HYPOmagnesemia, HYPOcalcemia).
  3. Medications (many cause QT prolongation).
  4. Ischemia.

Internal Medicine (106 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions