EKG Flashcards

1
Q

What types of pathology can we identify and study from ECGs?

A

Arrhythmias
MI and infarction
Pericarditis
Chamber hypertrophy
Electrolyte disturbances
Drug toxicity

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2
Q

What are the 12 leads?

A

3 limb leads (I, II, III)
3 Augmented leads (aVR, aVL, aVF)
6 Precordial leads (V1-V6)

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3
Q

Einthoven’s Triangle

A

An imaginary equilateral triangle having the heart at its center and formed by lines that represent the three standard limb leads of the electrocardiogram.

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4
Q

Lead I

A

Consists of positive electrode on the left arm looking toward the negative electrode on the right arm for electrical energy

Produces upward deflection of the QRS

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5
Q

Lead II

A

Consists of positive electrode on the left foot, negative electrode on the right arm.

Shows most upright QRS complexes and most prominent P wave

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6
Q

Lead III

A

Consists of positive electrode on the left foot, negative electrode on the left arm.

Produces upward QRS deflection

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7
Q

Lead aVR

A

Consists of positive electrode on the right arm- only limb lead on the right side of the body

Is the only lead with downward deflected QRS (normal EKG)

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8
Q

Lead aVL

A

Consists of positive electrode on the left arm, looks to the right and down.

Produces the least upright QRS among the limb leads.

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9
Q

Lead aVF

A

Consists of positive electrode on the left leg and looks straight up to the center of the chest.

Has very upright QRS complexes with prominent P waves.

Known as inferior lead (along with Leads II and III) because all look upward

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10
Q

Lead V1 location

A

Located at the right sternal border, forth intercostal space.

Lies above the right ventricle and septum

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11
Q

Lead V2 Location

A

Located at the left sternal border, fourth intercostal space.

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12
Q

Lead V3 Location

A

Located midway between leads V2 and V4

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13
Q

Lead V4 Location

A

Located at the midclavicular line, fifth intercostal space

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14
Q

Lead V5 Location

A

Located at the anterior axillary line, fifth intercostal space

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15
Q

Lead V6

A

Located at the midaxillary line, fifth intercostal space, above lateral wall of the left ventricle.

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16
Q

The QRS Axis

A

Represents the net overall direction of the heart’s electrical activity.

Leads I and aVF to determine axis. Normal = -30 degrees to 90 degrees.

Left axis deviation -30- -90 degrees

Right axis deviation 90- 180 degrees

Abnormality can mean ventricular enlargement or conduction blocks.

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17
Q

Bundle Branch blocks

A

Most common ECG abnormality

Appears as a wider than normal QRS complex

Occurs when one of the two bundle branches can’t conduct the impulse

Most common cause: ischemic heart disease

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18
Q

Right Bundle Branch Block

A

Impulse conduction to the right ventricle is blocked.

Examine lead V1 to identify.

ECG shows delayed or positive R wave (rabbit ears)

Key Identifier: QRS complex wider than 0.12 seconds with positive R wave in V1.

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19
Q

Left Bundle Branch Block

A

Electrical impulses don’t reach the left side of the heart.

QRS wider than 0.12 seconds.

Key Identifier: wide downward S wave or rS wave in leads V1 and V2.

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20
Q

What is the widow maker?

A

Left anterior descending coronary artery.

V1 and V2

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21
Q

Reciprocal Changes

A

Changes seen in the wall of the heart opposite the location of the infarction. These are normally seen at the onset of MI and are short lived.

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22
Q

Posterior Myocardial Infarction

A

Suggested by the following changes in V1-V3

  1. Horizontal ST depression
  2. Tall, broad R waves (>30ms)
  3. Upright T waves
    1. Dominant R wave (R/S ratio >1) in V2
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23
Q

Location of Posterior EKG leads

A

V7- Left posterior axiallary line, in the same horizontal plan as V6.

V8- Tip of the left scapula, in the same horizontal plane as V6

V9- Left paraspinal region, in the same horizontal plan as V6.

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24
Q

8 Step Process for Rhythm Interpretation

A
  1. Rate
  2. Rhythm
  3. P wave
  4. PR Interval
  5. QRS complex
    1. Ratio of P:QRS
  6. T wave
  7. QT
  8. Identify
    1. Ectopic beats
    2. Check ST segments
    3. U wave presence
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25
Q

EKG changes in Pericarditis

A

Typical ECG findings include diffuse concave-upward ST-segment elevation and, occasionally, PR-segment depression.

26
Q

What is an EKG?

A

Representation of the electrical events of the cardiac cycle. Each event has a distinct waveform, the study of which can lead to greater insight into a patient’s cardiac pathophysiology.

27
Q

P-Wave

A

Atrial depolarization/contraction

About .06-.10ms.

28
Q

QRS Complex

A

Ventricular depolarization

Normal .06-.10

29
Q

PR Interval

A

Time it takes for the electrical impulse to get from the atria to the bundle branch.

.12-.20ms.

30
Q

T-Wave

A

Ventricular Repolarization

31
Q

QT Interval

A

Less than half of the R-R

It represents the time it takes for the ventricles of the heart to depolarize and repolarize, or to contract and relax.

Normal- about .4-.44 seconds.

Longer in women and slower heart rates.

32
Q

U-Wave

A

Repolarization of the perkinje fibers

Seen more often in electrolyte imbalances

33
Q

EKG Paper

A

One small box = 0.04s

One large box = 0.20s

One large box vertically = 0.5mV (how strong)

Every 3 seconds (15 boxes) is marked by a vertical line

34
Q

6 Steps for Rhythm Analysis

A
  1. Calculate Rate
  2. Determine Regularity
  3. Assess the P waves
  4. Determine PR interval
  5. Determine QRS duration
  6. Determine QT interval
35
Q

Ways to Calculate EKG Rate

A
  1. Count the # of R waves in a 6 second strip then multiply by 10 or multiply by 6 in a 10 second strip. Works well for irregular rhythms.
  2. Rule of 300’s (300, 150, 100, 75, 60, 50) Good for regular rhythms.
36
Q

T Wave Inversion

Peaked T-wave

Flat T-wave

Hyperacute T-Wave

A

Inversion

  1. Coronary ischemia
  2. Wellen’s syndrome
  3. Left ventricular hypertrophy
  4. CNS disorder

Peaked- hyperkalemia

Flat- Coronary ischemia, hypokalemia

Hyperacute- can be the earliest EKG finding of ST-elevation MI and Prinzmetal angina.

37
Q

Appropriate T wave discordance

A

When a BBB is present, the T wave should be deflected opposite the terminal deflection of the QRS complex.

38
Q

J-Point

A

End of the QRS segment, beginning of the ST segment.

Some use this for determining fibrolytic therapy.

39
Q

Sinus Rhythm

A

Sinus node is the pacemaker firing 60-100 bpm. Each impulse is conducted normally through the ventricles.

No interventions.

40
Q

Sinus Bradycardia

  • Causes
  • Nursing Measures
A

Sinus node is firing at a rate less than 60 bpm. Each impulse is conducted normally through the ventricles.

Check vital signs, assess for symptoms.

Causes: Inferior wall MI, BB, hypothyroid, hypothermia

41
Q

Sinus Tachycardia

  • Causes
  • Nursing Measures
A

Sinus node is firing at a rate greater than 100 bpm. Each impulse is conducted normally through the ventricles.

Causes: caffeine, nicotine, alcohol ingestion, hypo or hyperthyroidism, digoxin toxicity.

Nursing Measures: Check vital signs including temperature. Assess for symptoms.

42
Q

Sinus Pause (<3 seconds) or Sinus Arrest (>3 seconds)

  • Causes
  • Nursing Measures
A

The normal sinus rhythm is interrupted by a lack of impulse formation from the sinus node. One or more PQRST complexes will be missing.

Causes- Acute infection, acute inferior wall MI, cardiac glycoside, quinidine or salicylate toxicity, CAD, Sick sinus syndrome, vagal stimulation.

Nursing Measures- Check vital signs including temperature, assess for symptoms.

43
Q

Wandering Atrial Pacemaker

A

The pacemaker site rotates between the sinus node, the atria, and the AV junction. Each impulse is conducted normally through the ventricles.

Different p-waves.

Causes: Increased vagal tone, inflamed or irritated atrial tissue resulting from rheumatic carditis, pulmonary disease with hypoxemia.

Nursing Measures

-Check vital signs. Normally asymptomatic, but with an irregular pulse.

44
Q

Paroxysmal Supraventricular Tachycardia

A

A single irritable site above the ventricle fires repetitively at a very rapid rate. Each impulse is conducted normally through the ventricles. May see a rapid rate start and stop which defines paroxysmal. May also see paroxysmal atrial tachycardia. (All of a sudden!)

Causes- dig toxicity, MI, cardiomyopathy, WPW syndrome (j-wave), COPD

Nursing Measures- Check vitals, Assess for symptoms.

45
Q

Atrial Flutter

  • Causes
  • Nursing Measures
A

A single irritable focus within the atria, which fires at a very rapid repetitive rate. The AV node is able to block some impulses from conducting through the ventricles.

Causes: chronic or acute disorder, transient complication of inferior wall MI, digoxin toxicity, alcoholism, cardiac surgery, hyperthyroidism.

Nursing Measures: Check vital signs, pt may have fast HR. Assess for symptoms.

46
Q

Atrial Fibrillation

  • Causes
  • Nursing Measures
A

Many irritable focuses within the atria, which first at a very rapid repetitive rate. The AV node still is able to control the impulses going through the ventricles which controls the heart rate.

-Causes: Increase in sympathetic activity, rheumatic heart disease, valvular disorders, HTN, MI, CHF, cardiomyopathy, COPD

47
Q

Junctional Rhythm

  • Causes
  • Nursing Measures
A

Originates in the AV junctional tissue at the rate of the inherent pacemaker which is 40-60 bmp (not sinus brady). Regular rhythm, normal QRS, no p-wave.

Causes: SSS, dig toxicity, increased vagal tone.

Nursing Measures: Vitals, monitor for s/s of decreased cardiac output. CP, diaphoresis, hypotension.

48
Q

First Degree AV Block

  • Causes
  • Nursing Measures
A

A conduction disturbance in which electrical impulses slow normally from the SA node through the atria but are delayed at the AV node. The AV node holds the impulse longer than normal before conducting it through to the ventrilces. PR longer than .20 seconds.

Causes: Drug toxicity, hypokalemia, hypothermia, hypothyroidism, prior MI.

Nursing Measures: Vital signs, usually asymptomatic unless HR slows.

49
Q

Second Degree AV Block Type 1

  • Causes
  • Nursing Measures
A

Wenckebach

The sinus node initiates the impulse, each one is delayed in the AV node a little longer than the preceding one until eventually one is blocked completely. This cycle is repeated, but it does not effect the conduction through the ventricles.

Causes: MI, BB, dig toxicity, increased vagal stimulation.

Nursing Measures: Check vitals, normally asymptomatic unless slow HR.

50
Q

Second Degree AV Block Type II

  • Causes
  • Nursing Measures
A

Mobitz

A delay or interruption of the conduction originating in the AV node in which a dropped beat occurs without warning. The abnormal conduction is in the bundle of His of the bundle branches. More serious than Type 1. Dropped beat without warning.

Causes: Organic heart disease, Anterior Wall MI, Severe CAD

Nursing Measures: Check vitals, if HR slows may be symptomatic, assess for symptoms.

51
Q

Third Degree Heart Block

  • Causes
  • Nursing Measures
A

All atrial impulses are blocked at the av junction, and the atria and ventricles are beating independently. This may be a chronic or acute condition. All other blocks can progress to this. The PR intervals vary.

Causes: severe dig toxicity, bb or ccb, anterior or inferior wall MI, complications from atrial septal defects, mitral valve repair.

Nursing Measures- check vital signs, assess for symptoms of decreased HR.

52
Q

Ventricular Tachycardia

  • Causes
  • Nursing Measures
A

More than 3 PVCs in a row. HR normally greater than 100bpm. Can be paroxysmal or sustain for a period of time. Life-threatening arrhythmia.

Causes: Acute MI, cardiomyopathy, electrolyte imbalance, heart failure, mitral valve prolapse, pulmonary embolism.

Nursing Measures: Vitals, check patient, assess for symptoms if no pulse and full code call a code blue.

53
Q

Ventricular Fibrillation

  • Causes
  • Nursing Measures
A

It is composed of multiple foci in the ventricles that become irritable and generate chaotic disorganized impulses, which in turn causes the heart to just quiver.

Causes: acute MI, digoxin, epinephrine or quinidine toxicity, electric shock, hypothermia, electrolyte imbalance.

Nursing Measures: Check patient, call a code blue, defibrillate.

54
Q

Asystole

A

Heart has lost all electrical activity.

Causes: severe metabolic deficit, acute respiratory failure, extensive myocardial damage possibly from ischemia.

Nursing Measures: Verify in 2 leads, check pulse, call code blue.

55
Q

Lead V2, V3, V4

A

Anterior

Mid left anterior descending of diagonal branch LAD

56
Q

Lead II, II, aVF

A

Inferior

Right or Posterolateral circumflex

57
Q

Lead I, aVL, V5, V6

A

Lateral

Circumflex or lateral ventricular branch

58
Q

Lead V1 and V2

A

Septum

Left anterior descending

59
Q

Tall R wave in Lead V1, V7, V8, V9

A

Posterior

Posterolateral of circumflex or posterior descending of right

60
Q

Lead V3r, V4r

A

Right Ventricle

Right Coronary

61
Q

Lead I, aVL, V2-V6

A

Anterolateral

Proximal left anterior descending

62
Q

Lead II, III, aVF, I, aVL, V5, V6

A

Inferolateral

Proximal circumflex or large lateral ventricle in left dominant system