Fall Quiz 2 Flashcards

0
Q

What is the difference between a compensatory and non compensatory premature beat?

A

A compensatory premature beat will have QRS complexes that march out evenly before and after the pause.

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1
Q

What is a premature beat?

A

When an irritable ectopic focus fires prematurely.

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2
Q

What is an escape beat?

A

When the SA node doesn’t fire at its regular interval and an ectopic focus fires.

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3
Q

What is a reentry circuit?

A

A group of cardiac cells that depolarize in a circular pattern that is rapid and repetitive.

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4
Q

What is the underlying mechanism of most tachydysrhytmias?

A

Reentry circuits

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5
Q

What are the 2 types of reentry circuits?

A

Macroentry & Microentry

This refers to the amount of tissue that is affected by the circuit.

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6
Q

List the 3 conditions necessary to establish a reentry circuit.

A
  1. Two separate parallel paths of impulse conduction.
  2. Slowed conduction or complete unidirectional block in one of the pathways.
  3. The right timing of the absolute refractory period.
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7
Q

What is Wolf Parkinson White Syndrome? (WPW)

A

A macroreentry pathway where an accessory pathway provides secondary access to the ventricles.

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8
Q

List 6 types of Atrial Rhythms.

A
W:  Wandering atrial pacemaker (WAP)
E:  Ectopic atrial tachycardia (EAT)
A:  Atrial Fibrillation (AFib)
P:  Premature atrial contraction (PAC)
M:  Multifocal atrial tachycardia (MAT)
A:  Atrial Flutter
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9
Q

Explain WAP

A
  • Regular to irregularly irregular
  • Wandering Atrial Pacemaker
  • Pacemaker shifts between multiple foci (impulse origins)
  • must have at least 3 different p-wave morphologies
  • normal rate (60-100)
  • normal QRS (less than 0.12)
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10
Q

Explain MAT rhythm.

A
  • Regular to irregularly irregular
  • Multifocal Atrial Tachycardia
  • Tachycardic version of WAP
  • 3 different pwave morphologies
  • Less common than, and easy to confuse with AFib
  • look for inverted pwaves to differentiate from AFib
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11
Q

Explain PAC rhythm.

A
  • Premature Atrial Contraction
  • Results from premature discharge of an ectopic atrial focus.
  • characterized by a premature abnormal pwave.
  • pwave may be buried in twave.
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12
Q

List 3 causes of PAC

A

Caffeine
Sympathomimetics
Hypoxia

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13
Q

What is a nonconducted PAC

A

It is a premature atrial contraction from an ectopic focus that is not transmitted through the AV node, resulting in a premature pwave with no corresponding QRS.

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14
Q

Explain EAT rhythm.

A
  • Ectopic Atrial Tachycardia
  • regular rhythm
  • results from increased automaticity from an ectopic atrial focus or microreentry circuit.
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15
Q

Explain AFib.

A
  • Atrial fibrillation
  • caused by many irritable atrial foci firing at once, causing chaos.
  • only some impulses are transmitted through the AV node resulting in irregularly irregular rhythm.
  • PRI: non-existent
  • QRS: <0.12
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16
Q

List some etiology of AFib.

A
  • Atrial enlargement
  • Age
  • Pericarditis
  • Coronary artery disease
  • MI
  • hypertension
  • Alcohol abuse
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17
Q

List 2 problems associated with chronic AFib.

A
  • Reduced cardiac output

* blood clots formed in the atria can lead to embolism or stroke

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18
Q

Explain Atrial Flutter

A
  • rapid discharge of single ectopic focus causing atrial rate of 250-500 (usually 300)
  • usually a regular rhythm
  • is an example of a macro-reentry circuit
  • rare - usually converts on its own.
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19
Q

Name the 4 junctional rhythms.

A

PJC: Premature Junctional Contraction
Junctional rhythm
Accelerated junctional rhythm
Junctional tachycardia

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20
Q

Describe what junctional p-waves look like.

A

No p-wave or inverted p-wave and occasionally retrograde

p-waves.

21
Q

Describe a PJC.

A

Premature junctional contraction.
Caused by a premature discharge of an ectopic focus in the AV node.
Absent, inverted, or retrograde p-waves.
Usually a regular underlying rhythm.

22
Q

Explain junctional rhythm.

A
Rhythm that originates in the AV node as the SA node has either slowed or failed.
Rhythm: regular
Rate: 40-60
P-waves: absent, inverted or retrograde
QRS: narrow
23
Q

What is accelerated junctional rhythm?

A

Same as junctional rhythm with a rate of 60-100

24
Q

What is junctional tachycardia?

A

Same as junctional rhythm with a rate over 100

25
Q

Describe AVNRT

A

AV node reentrent tachycardia
About 10% of population have 2 pathways through the AV node
Sometimes a reentry circuit develops if the conditions are right
*regular
*very rapid
*no discernible p-waves
*narrow QRS

26
Q

Describe AVRT.

A

AV reentrant tachycardia
Can occur when an accessory pathway connects the atria and ventricles
WPW (wolf Parkinson white) is the most common

27
Q

List the 4 rhythms that are very difficult to tell apart and that (for this class) are referred to as SVT (supraventricular tachycardia)

A

EAT: ectopic atrial tachycardia
Junctional tachycardia
AVNRT
AVRT

28
Q

What is the general formula for Determining a patients natural maximum heart rate (sinus heart rate)?

A

220-age.

This formula can help determine between SVT and sinus tach

29
Q

How do you differentiate an inverted junctional p-wave from an inverted atrial p-wave?

A

PRI less than 0.12 is considered junctional.

PRI longer than 0.12 is considered atrial.

30
Q

By definition, where do all ventricular rhythms originate?

A

In the ventricles, below the bundle of His

31
Q

Describe ventricular QRS complexes?

A

They are ALL wide

32
Q

Define and describe a PVC

A

Premature Ventricular Contraction

  • results from an ectopic focus in the ventricles
  • no p-wave
  • wide QRS, often distorted or bizarrely shaped
33
Q

What is the difference between a unifocal and Multifocal PVC?

A

Unifocal have the same focus, Multifocal have numerous foci.

34
Q

What is bigeminy? Trigeminy?

A

Bigeminy: when every other beat is a PVC
Trigeminy: when every 3rd beat is a PVC

35
Q

Name 6 etiology of PVC’s

A
Sympathomimetics
Hypoxia
Caffeine
Idiopathic
Myocardial ischemia
Electrolyte imbalance
36
Q

What are the characteristics of Ventricular Escape Rhythm?

A
Rhythm: regular
Rate:  less than 40
P-waves: none
PRI: none
QRS: wide, sometimes bizarre
37
Q

List 3 etiology of ventricular escape rhythm

A

Damage to higher pacemaker
Complete heart block
First successful rhythm following defibrillation

38
Q

What is accelerated Ventricular rhythm?

A

Same as ventricular rhythm with a rate of 40-100

39
Q

Describe ventricular tachycardia

A

Rhythm: regular or slightly irregular
Rate: greater than 100-250

40
Q

List 4 vtach etiology

A
Acute MI
Myocardial ischemia
Electrolyte imbalances
Acid base disturbances
**nearly all vtachs occur because of micro reentry circuits due to slow or non-conducting tissue
41
Q

What is Torsades de Pointes?

A

A polymorphic vtach
Frequently occurs in the setting of prolonged QT
Treated with mag sulfate

42
Q

Why is prolonged QTI problematic?

A

Because of the excessive relative refractory period.

43
Q

Describe Vfib.

A

Completely chaotic electrical activity in the ventricles.

Always pulseless.

44
Q

Name 5 etiology of Vfib.

A
MI
Hypoxia
Electrolyte imbalances
Electrical shock
Drugs
45
Q

Describe asystole.

A

No electrical activity

Final ECG in all deaths

46
Q

Describe bundle branch blocks.

A

Must originate supraventrically
Wide QRS
Can be identified generically in lead II
12-lead needed to differentiate the side of the block

47
Q

What type of pacemaker only fires when the intrinsic ones fail?

A

A “demand” pacemaker

48
Q

Define the term “ventricular capture”

A

When a pacemaker spike is followed by a wide QRS

49
Q

Define “intrinsic beat”

A

A beat from the hearts own rhythm.

50
Q

Define a fusion beat.

A

A complex formed when a paced beat fires simultaneously with an intrinsic beat.