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EKG Certification > Chapter 5 > Flashcards

Chapter 5 Flashcards

1
Q

Why is there a delay in the electrical impulse?

A

Allows the atria to contract and complete filling of ventricles before the next ventricular contraction

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2
Q

Job of the Bundle of His?

A

Connects AV node with bundle branches

Has pacemaker cells capable of discharging at a rhythmic rate of 40-60bpm

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3
Q

When would the AV junction assume responsibility for pacing the heart? Why?

A

The AV junction will assume responsibility when the SA node fails to discharge (sinus arrest)

SA node impulse is generated but blocked as it exists the SA node (SA block)

The rate of discharge of the SA node is slower than that of the AV junction (sinus bradycardia or the slower phase of the sinus arrhythmia)

An impulse from the SA node is generated and is conducted through the atria but is not conducted to the ventricles (AV block)

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4
Q

In what direction does the electrical impulse travel to activate the atria?

A

If the AV junction paces the heart, the electrical impulse must travel in a backward (retrograde) direction to activate the atria

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5
Q

Sinus arrest

A

Missing beat - SA node not firing properly - after missing beat, next one is late

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6
Q

AV junction (P waves)

A
  1. With a sinus rhythm, the P wave is positive (upright) because the wave of depolarization is moving toward the positive electrode
  2. P wave associated with a junctional beat may be inverted (retrograde) and appear before the QRS
  3. P wave may be hidden by the QRS
  4. P wave can appear after the QRS
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7
Q

Premature Junctional Complexes (PJC)

A

Occurs when an irritable site within the AV node junction fires before the next expected sinus beat

QRS will usually measure 0.11sec or less (narrow QRS - supraventricular)

Often followed by a noncompensatory (incomplete) pause

May occur in patterns

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8
Q

How to recognize PJCs?

A

Rhythm: irregular because of the premature beats

Rate: usually within normal range but depends on underlying rhythm

P waves: may occur before, during or after the QRS; if visible, the P wave is inverted in leads II, III, and aVF

PR interval: if a P wave occurs before the QRS, the PR interval will usually be 0.12 sec or less; if no P wave occurs before the QRS, there will be no PR interval

QRS duration: 0.11sec or less unless abnormally conducted

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9
Q

What causes PJCs?

A
  1. Acute coronary syndromes
  2. Digitalis toxicity
  3. Electrolyte imbalance
  4. Heart failure
  5. Mental and physical fatigue
  6. Rheumatic heart disease
  7. Stimulants (caffeine, tobacco, cocaine)
  8. Sympathomimetics
    9.valvular heart disease
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10
Q

What to do about PJCs?

A

Most individuals with PJCs are asymptomatic

PJCs may lead to symptoms of palpitations or the feeling of skipped beats

Lightheadedness, dizziness, and other signs of decreased cardiac output can occur if PJCs are frequent

If PJCs occur because of the ingestion of stimulants or digitalis toxicity, these substances should be withheld.

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11
Q

Junctional Escape Beats

A

Junctional escape beat originates in the AV junction and appears LATE (after the next expected beat of the underlying rhythm

A JEB is protective - preventing cardiac standstill

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12
Q

Characteristics of a Junctional escape beat

A

Rhythm: irregular because of the late beat

Rate: depends on rhythm

P waves: inverted before or after QRS or absent

PR interval: 0.12-0.20sec and constant

QRS duration: 0.11sec or less (narrow)

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13
Q

Junctional Escape Rhythm

A

When you have 3 JEB in a row, it is called a junctional escape rhythm

Several sequential junctional escape beats

Intristic rate of the AV junction is 40-60bpm

If the AV junction paces the heart at a rate slower than 40bpm, the resulting rhythm is called junctional bradycardia

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14
Q

How to recognize junctional rhythm?

A

Rhythm: regular

Rate: 40-60bpm

P waves: may occur before, during or after the QRS; if visible, the P wave is inverted in leads II, III, and aVF

PR interval: if P wave occurs before QRS, the PR interval will usually be 0.12sec or less; if no P wave occurs, there will be no PR interval

QRS duration: 0.11sec or less unless abnormally conducted (narrow)

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15
Q

Causes of junctional rhythm

A
  1. Acute coronary syndrome (notably inferior wall MI)
  2. Effects of medications including amiodarone, beta blockers, calcium channel blockers, digitalis
  3. Hypokalemia
  4. Immediately after cardiac surgery
  5. Increased parasympathetic tone
  6. Obstructive sleep apnea
  7. Rheumatic heart disease
  8. SA node disease
  9. valvular disease
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16
Q

What to do about junctional rhythm? (asymptomatic)

A

Patient may be asymptomatic or may experience signs and symptoms associated with the slow heart rate and decreased cardiac output

If the patient is experiencing symptoms, try to determine their frequency, timing, duration, severity, longevity, circumstances, triggers, and alleviating factors

17
Q

What to do about junctional rhythm? (Signs and symptoms related to slow heart rate)

A
  1. Apply a pulse oximeter
  2. Administer supplemental oxygen, if indicated
  3. Establish intravenous (IV) access
  4. Obtain a 12 lead ECG
  5. Administer IV atropine
  6. Reassess the patient; continue monitoring
18
Q

Accelerated Junctional Rhythm

A

An ectopic rhythm caused by abnormal automaticity of the bundle of his

Results in regular ventricular response at rate of 60-100bpm

19
Q

How to recognize atrial junctional rhythm?

A

Rhythm: regular

Rate: 60-100bpm

P waves: may occurs before, during or after the QRS; if visible, the P wave is inverted in leads II, III, and aVF (retrograde P waves)

PR intervals: if a P wave occurs before the QRS, the PR interval will usually be 0.12sec or less; if no P wave occurs before the QRS, no PRI

QRS duration: 0.11sec or less unless abnormally conducted (narrow)

20
Q

What causes AJR?

A
  1. Acute myocardial infraction
  2. Cardiac surgery
  3. Chronic obstructive pulmonary disease
  4. Digitalis toxicity
  5. Hypokalemia
  6. Rheumatic fever
21
Q

What to do about AJR?

A

Patient may be asymptomatic but monitor closely

If the rhythm is caused by digitalis toxicity, this medication should be withheld

22
Q

Junctional tachycardia

A

Ectopic rhythm that begins in the bundle of his

Exists when three or more sequential PJCs occur at a rate more than 100bpm

23
Q

How to recognize junctional tachycardia?

A

Rhythm: ventricular rhythm usually regular, but may be irregular

Rate: 101-220bpm

P waves: may occur before, during or after the QRS; if visible the P wave is inverted in leads II, III, aVF (retrograde P waves - before QRS)

PR interval: none

QRS duration: 0.11sec or less - narrow QRS

24
Q

Nonparoxysmal (gradual onset) junctional tachycardia

A

Benign dysrhythmia that is usually associated with a gradual increase in rate

Rarely exceeds 120bpm

25
Q

Paroxysmal junctional tachycardia

A

Starts and ends suddenly

Often precipitated by a PJC

Ventricular rate is generally faster, at a rate of 140bpm or more

26
Q

What causes junctional tachycardia?

A

Disorder of impulse formation (automaticity)

Uncommon in adults but may occur because of
-acute coronary syndromes
-digitalis toxicity
-heart failure
-theophylline administration

27
Q

What to do about junctional tachycardia?

A

Patient may be asymptomatic

With sustained ventricular rates of 150bpm or more, the patient may complain of fatigue, palpitations or chest discomfort or may experience syncope

Decreased cardiac output may result because of the fast ventricular rate

Depending on severity of the symptoms

Observe patient and if symptomatic:
-apply pulse oximeter, administer oxygen
-establish IV access
-obtain 12 lead ECG
-Vagal maneuvers, adenosine
-Possible beta blocker, calcium channel blocker, if no contraindications exist
-synchronized cardioversion is not indicated

28
Q

Select the correct statements about PJCs
A. A noncompensatory (incomplete) pause often follows a PJC
B. Unlike premature atrial complexes, PJCs do not occur in patters
C. If seen, the P wave of a PJC is negative and may appear before or after the QRS complex
D. A PJC begins within the AV junction and appears earlier than the next expected beat of the underlying rhythm

A

A, C, D

29
Q

An accelerated junctional rhythm is identified by a regular ventricular response occurring at the rate of:
A. 20 to 40bpm
B. 40 to 60bpm
C. 61 to 100bpm
D. 101 to 180bpm

A

C

30
Q

The term junctional bradycardia is used to describe a rhythm that is junctional in origin with:
A. An atrial rate of 40 to 60bpm
B. An atrial rate slower than 60bpm
C. A ventricular rate of 40 to 60bpm
D. A ventricular rate slower than 40bpm

A

D

31
Q

When viewing a junctional rhythm in lead II, where is the P wave location on the ECG if ventricular depolarization precedes atrial depolarization?
A. Before the QRS complex
B. During the QRS complex
C. After the QRS complex

A

C

32
Q

In rhythms originating from the AV junction, the QRS duration is typically _________ or less unless an intraventricular conduction delay exists
A. 0.04sec
B. 0.11sec
C. 0.14sec
D. 0.20sec

A

B

33
Q

Select the correct statements regarding junctional dysrhythmias
A. The intrinsic rate of the AV junction is 40 to 60bpm
B. Junctional dysrhythmias may be seen in acute coronary syndromes
C. An accelerated junctional rhythm is a potentially life threatening dysrhythmia
D. The ventricular rhythm associated with junctional dysrhythmias is usually very regular

A

A, B, D

34
Q

The primary waveform used to differentiate PJCs from PACs is the
A. P wave
B. Q wave
C. R wave
D. T wave

A

A

35
Q

A 63 year old man is complaining of dizziness that began about 45min ago while cleaning his garage. Because the patients oxygen level on room air was 88%, supplemental oxygen is being administered. The cardiac monitor has been applied, revealing the rhythm in Fig. 5.10. A coworker is attempting to establish intravenous access.

Which of the following statements are true about this patients cardiac rhythm?
A. The atrial rhythm is regular
B. The QRS complex is narrow
C. ST segment elevation is present
D. The ventricular rhythm is regular
E. There are more P waves than QRS complexes

A

B, D

36
Q

A 63 year old man is complaining of dizziness that began about 45min ago while cleaning his garage. Because the patients oxygen level on room air was 88%, supplemental oxygen is being administered. The cardiac monitor has been applied, revealing the rhythm in Fig. 5.10. A coworker is attempting to establish intravenous access.

The rhythm shown on the cardiac monitor is
A. Sinus bradycardia
B. Junctional bradycardia
C. Junctional escape rhythm
D. Accelerated junctional rhythm

A

B

37
Q

A 63 year old man is complaining of dizziness that began about 45min ago while cleaning his garage. Because the patients oxygen level on room air was 88%, supplemental oxygen is being administered. The cardiac monitor has been applied, revealing the rhythm in Fig. 5.10. A coworker is attempting to establish intravenous access.

The patients blood pressure is 82/50mm hg. Ventilation is 16. He states his normal blood pressure is about 130/80mm hg. The patient denies chest discomfort and states that he takes no prescription medication. His skin is cool, pink and moist, and his breath sounds are clear. Intravenous access has been successfully established. Based on the information provided, which of the following states is true regarding this patient situation?
A. Because the patient is symptomatic with this rhythm, a vagal maneuver should be attempted
B. The patient is symptomatic with this rhythm. Obtain a 12 lead ECG then administer atropine IV
C. Therapeutic interventions are not indicated because there is no evidence of ST segment elevation on the cardiac monitor
D. Although the patient is complaining of dizziness, this symptom does not warrant any further intervention other than cardiac monitoring at this time

A

B

EKG Certification (9 decks)

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