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EKG Midterm > 4 Atrial and Ventricular Dysrhythmias > Flashcards

4 Atrial and Ventricular Dysrhythmias Flashcards

1
Q

Sinus rhythms originate from…

A

The sinoatrial (SA) node

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2
Q

During normal heart activity, the _____ acts as the primary pacemaker

A

SA node

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3
Q

NSR is ____ dependent

A

Age

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4
Q

NSR for newborns

A

110-150 bpm

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5
Q

NSR for 2 year olds

A

85-125 bpm

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6
Q

NSR for 4 year olds

A

75-115 bpm

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7
Q

NSR for 6+ year olds

A

60-100 bpm

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8
Q

Describe sinus bradycardia

A

HR < 60bpm

Rhythm is regular

P waves normal and homogenous

QRS complexes are normal and homogenous

PR intervals are normal

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9
Q

Examples of causes of sinus bradycardia

A

Cardiac diseases

Use of certain drugs (ie Digoxin, beta blockers, CCBs, Li, Amiodarone, propafenone, quinidine)

Excessive vagal tone or decreased sympathetic stimulation

Noncardiac disorders

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10
Q

_____ can result if the heart rate slows to the point where cardiac output drops significantly

A

Hypotension

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11
Q

Patients are less tolerant to bradycardia if HR < _____

A

45bpm

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12
Q

Describe Sinus Tachycardia

A

Rate is between 100 and 160 bpm

Rhythm is regular

P waves normal and all look alike (one precedes each QRS)

QRS complexes are normal and all look alike

PR intervals are normal

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13
Q

Examples of causes of Sinus Tachycardia

A

Cardiac Diseases (CHF, cardiogenic shock, pericarditis)

Use of certain drugs (sympathomimetics, dopamine, dobutamine, vagolytic drugs like atropine, caffeine, nicotine, amphetamines)

Increased sympathetic stimulation

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14
Q

Sinus tachycardia can increase….

A

Myocardial oxygen consumption —> aggravation of ischemia (bringing on CP) and infarction, particularly in those with CVD

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15
Q

Sinus Dysrhythmia is also known as…

A

Sinus arrhythmia

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16
Q

Sinus dysrhythmia is the same as NSR except…

A

There is a patterned irregularity

Cycle of slowing, then speeding up, then slowing again

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17
Q

What does respiration have to do with sinus dysrhythmia?

A

The beat-to-beat variation produced by irregular firing of the SA node usually corresponds with the respiratory cycle and changes in intrathoracic pressure

HR increases during inspiration and decreases during expiration

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18
Q

Sinus dysrhythmia can occur naturally in…

A

Athletes
Children
Older adults

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19
Q

Pathological conditions —> sinus dysrhythmia

A

Patients with heart disease or inferior wall MI

Individuals receiving certain drugs (digitalis and morphine)

Conditions in which there is increased intracranial pressure

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20
Q

Sinus dysrhythmia is usually of no clinical significance and produces no symptoms, but in some patients…

A

It may be associated with palpitations, dizziness, and syncope

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21
Q

Sinus pause/arrest occurs when…

A

The SA node transiently stops firing —> short periods of cardiac standstill until a lower-level pacemaker discharges or the SA node resumes its normal function

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22
Q

Sinus pause is when _____ beats are dropped, where as Sinus arrest is ______ beats dropped

A

1-2

3+

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23
Q

Most prominent characteristic of sinus pause/arrest on ECG

A

A flatline

Pause —> irregularity

Rhythm typically resumes its normal appearance after pause, unless an escape pacemaker resumes the rhythm

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24
Q

Describe sinus arrest

A

Rate typically between 60-100 bpm

Rhythm irregular

P waves are normal but are absent where there is a pause in rhythm

QRS complexes are normal and all look alike but are absent where there is a pause in rhythm

PR intervals are normal but absent where there is a pause in rhythm

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25
Q

Causes of sinus arrest

A

SA disease (fibrosis, degeneration)

Cardiac disorders (chronic CAD, MI, acute myocarditis, CM)

Use of certain drugs (digoxin, Procainamide, quinidine, salicylates, excessive doses of beta blockers or CCBs)

Increased vagal tone (valsalva, carotid sinus massage, vomiting)

Hyperkalemia

Hypoxia

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26
Q

What are some other names for Sinus Node Dysfunction?

A

Sick Sinus Syndrome

Brady-tachy syndrome

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27
Q

Sick Sinus Syndrome is primarily a disease of the ______ due to ________

A

Elderly

Degenerative disease of the SA node

(But it can occur in younger people too)

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28
Q

Sick Sinus Syndrome is characterized by …

A

Periods of bradycardia, tachycardia, prolonged pauses or alternating bradycardia and tachycardia

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29
Q

Treatment for Sick Sinus Syndrome

A

May require a pacemaker for the slow rhythms and medication for the fast rhythms

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30
Q

Atrial dysrhythmias originate in …

A

The atrial tissue or in the internodal pathways

Believed to be caused by three mechanisms:
Automaticity
Triggered activity
Recently

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31
Q

Atrial dysrhythmias can affect _______ and ____________, leading to ________

A

Ventricular filling time

Diminish the strength of the atrial contraction

Decreased CO and ultimately decreased tissue perfusion

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32
Q

Key characteristics of Atrial dysrhythmias

A

P waves that differ in appearance from normal sinus P waves (P’ waves)

Abnormal, shortened, or prolonged PR intervals

QRS complexes that appear narrow and normal

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33
Q

What is wandering atrial pacemaker?

A

Pacemaker site shifts between the SA node, atria, and/or AV junction

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34
Q

Most characteristic feature of Wandering Atrial Pacemaker

A

P waves that change in appearance (3 or more)

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35
Q

Describe Wandering atrial pacemaker

A

Rate normal (60-100bpm)

Slightly irregular rhythm

P waves differ continually**

QRS complexes normal/consistent

PR intervals vary (can be normal, short, long)

QT interval WNL

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36
Q

Wandering atrial pacemaker is generally caused by …

A

The inhibitory vagal effect of respiration on the SA node and AV junction

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37
Q

Wandering atrial pacemaker can be a normal finding in…

A

Children
Older adults
Well-conditioned athletes

No usually of any clinical significance, but may be related to some types of organic heart disease, esp DIGITALIS

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38
Q

Early ectopic beats that originate outside the SA node

A

Premature Atrial Complexes (PACs)

Produce an irregularity in the rhythm

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39
Q

Describe Premature Atrial Complexes

A

Have P waves that are upright (in lead II), preceding each QRS complex but have a different morphology than the normal P waves of the underlying rhythm

Followed by a non-compensatory pause

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40
Q

What is a non-compensatory pause?

A

A pause where there are less than two full R-R intervals between the R wave of the normal beat which precedes the PAC and the R wave of the first normal beat which follows it

The PAC inhibits and “resets” the SA node

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41
Q

Characteristics of PACs

A

Rate depends on underlying rhythm

Irregular rhythm due to the early beat

P waves may be upright or inverted, will appear different than those of the underlying rhythm

Normal QRS

PR interval varies

QT WNL or possibly shortened

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42
Q

Possible causes of PACs

A

Cardiac disease (Coronary or valvular heart disease, pulmonary disease)

Use of certain drugs (DIGITALIS**)

Acute resp failure, hypoxia, electrolyte imbalances, fever, alcohol, cigarettes, anxiety, fatigue, ID

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43
Q

If someone has taken too much digitalis, expect…

A

Premature Atrial Complexes (PACs)

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44
Q

When are PACs considered significant?

A

Isolated PACs in patients with healthy hearts

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45
Q

PACs may predispose a patient with heart disease to more serious dysrhythmias such as…

A

Atrial tachycardia
Atrial flutter
Atrial fibrillation

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46
Q

PACs can serve as an early indicator of ________ or _________ in patients experiencing an acute MI

A

Electrolyte Imbalance

CHF

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47
Q

What are the three categories of PACs?

A

Bigeminal (Normal, PAC, Normal, PAC, Normal, PAC)

Trigeminal (Normal, Normal, PAC, Normal, Normal, PAC)

Quadrigeminal (Normal, Normal, Normal, PAC)

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48
Q

PACs may have wide QRS complexes when seen with…

A

Abnormal ventricular conduction

They can therefore be easily confused with PVCs (PACs with aberrant ventricular conduction)

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49
Q

What helps distinguish PACs from PVCs?

A

PACs usually do not have a compensatory pause

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50
Q

What is Atrial Tachycardia?

A

Rapid dysrhythmia (rate of 150-250bpm) that arises from the atria

Rate is so fast it overrides the SA node

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51
Q

Characteristics of atrial tachycardia

A

Rate 150-250bpm

Regular rhythm unless the onset is witnessed

P waves may be upright or inverted, but will appear different than those of the underlying rhythm (can also be hidden in preceding T wave)

QRS normal

PR intervals can be normal, shorter than normal or immeasurable if the P waves are hidden

QT WNL

52
Q

Possible causes of atrial tachycardia

A

Sinus node disease (ie Sick Sinus)

Cardiac disorders (MI, CM, congenital anomalies, Wolff-Parkinson-White syndrome, valvular heart disease, systemic HTN, cor pulmonale)

Use of certain drugs (digitalis*****)

Hyperthyroidism

53
Q

What is the most common cause of atrial tachycardia?

A

DIGITALIS TOXICITY

54
Q

Atrial tachycardia may occur in ______ or may be ________

A

Short bursts (Paroxysmal atrial tachycardia) or may be sustained

Short bursts are well tolerated in otherwise normally healthy people

55
Q

What can occur with sustained atrial tachycardia?

A

Ventricular filling may not be complete during diastole —> compromised CO in patients with underlying heart disease

May increase myocardial ischemia —> MI

56
Q

Pathological condition that presents with changing P wave morphology and heart rates of 120-150 bpm

A

Multifocal Atrial Tachycardia (MAT)

The rhythm is irregular due to the multiple Fock

57
Q

Multifocal Atrial Tachycardia has the same features as _________ but faster rate

A

Wandering atrial pacemaker

May be confused with atrial fibrillation as well

58
Q

Supraventricular Tachycardia (SVT) arises from…

A

Above the ventricles but cannot be definitely identified as atrial or junctional tachycardia because the P waves cannot be seen sufficiently

Includes Paroxysmal SVT, Nonparoxysmal atrial tachycardia, and multifocal atrial tachycardia

59
Q

Rapid depolarization re-entry circuit in the atria with a rate of 250-350bpm

A

Atrial Flutter

60
Q

What dysrhythmia produces p waves that have a characteristic saw-tooth appearance?

A

Atrial flutter (“F waves”)

61
Q

Characteristics of Atrial Flutter

A

Ventricular rate may be slow, normal, or fast but atrial rate is between 250-350bpm

Regularity - may be reg or irregular

P waves - absent, instead there are F waves

QRS normal

PR immeasurable

QT immeasurable

62
Q

Possible causes of atrial flutter

A

Conditions that enlarge atrial tissue and elevate atrial pressures

COPD, hypoxia, digitalis, hyperthyroidism, infection, catecholamines

May occur in healthy people who use coffee, alcohol, or cigarettes or who are fatigued/under stress

63
Q

Chaotic, asynchronous firing of multiple areas within the atria (>350bpm)

A

Atrial fibrillation

64
Q

Characteristics of atrial fibrillation

A

Totally irregular rhythm with no discernible p waves - instead there is a chaotic baseline of fibrillatory f waves representing atrial activity

65
Q

Atrial fibrillation leads to loss of ….

A

Atrial kick —> decreased CO by up to 25%

Patients may develop intra-atrial emboli as the atria are not contracting and blood stagnates in the atrial chambers forming a thrombus

66
Q

Why are patients with a fib more predisposed to stroke?

A

Patients can develop intra-atrial emboli as the atria are not contracting and blood stagnates in the atrial chambers —> thrombus

67
Q

Where do junctional dysrhythmias originate?

A

In the AV junction (area around AV node and bundle of His)

68
Q

Key characteristics of junctional dysrhythmias

A

P waves may be inverted with a short PR interval, they may be absent (buried in QRS complex) or they may follow QRS complexes

QRS complexes are usually normal (unless there is an intraventricular conduction defect, aberrancy, or pre-excitation)

69
Q

Single early electrical impulse that arises from the AV junction

A

Premature Junctional Complex (PJC)

70
Q

Characteristics of Premature Junctional Complexes

A

Rate depends on underlying rhythm

Irregular rhythm due to early beat

P waves will be INVERTED - may precede, be buried in, or follow the QRS complex

QRS complex is normal

PR interval short

QT WNL

PJCs are followed by a non-compensatory pause

71
Q

Possible causes of PJCs

A

Cardiac disorders (Ischemia, acute MI, damage to AV junction, CHF, valvular disease, rheumatic heart disease, swelling of AV junction after surgery)

Certain drugs (digitalis, cardiac meds, sympathomimetic drugs)

Excessive caffeine, tobacco, or alcohol, increased vagal tone, hypoxia, electrolyte imbalance (particularly Mg and K), exercise

72
Q

What is junctional escape rhythm?

A

Arises from AV junction at a rate of 40-60 bpm

Regular rhythm

P waves are inverted and may be before, during, or after QRS

QRS normal

If present, PR intervals shorter than normal

QT normal

73
Q

Possible causes of junctional escape rhythm

A

Increased vagal tone, sick sinus syndrome, inferior wall MI, rheumatic heart disease, valvular disease

Certain drugs (digitalis, quinidine, beta blockers, CCBs)

Post cardiac surgery, hypoxia

74
Q

Accelerated junctional rhythms arise from…

A

The AV junction at a rate of 60-100 bpm but with inverted P waves

75
Q

Characteristics of accelerated junctional rhythms

A

60-100bpm

Regular rhythm

Inverted p waves

Normal QRS

PR intervals short if present

QT normal

76
Q

Fast ectopic rhythm that arises from bundle of His at rate of 100-180 bpm

A

Junctional tachycardia

77
Q

Characteristics of junctional tachycardia

A

100-180 bpm

Regular rhythm

Inverted P waves

Normal QRS

Short PR interval if present

QT WNL

78
Q

Why are ventricular dysrhythmias potentially life threatening?

A

The ventricles are ultimately responsible for cardiac output

79
Q

Ventricular dysrhythmias occur when…

A

The atria, AV junction, or both are unable to initiate an electrical impulse

There is enhanced automaticity of the ventricular myocardium

80
Q

Key features of ventricular dysrhythmias

A

Wide (>0.12s), bizarre QRS complexes

T waves in the opposite direction of the R wave

Absence of P waves

81
Q

What are the different types of ventricular dysrhythmias?

A

Premature Ventricular Complexes (PVC)

Idioventricular rhythm

Accelerated idioventricular rhythm

Ventricular Tachycardia

Ventricular fibrillation

Asystole

82
Q

Early ectopic beats that interrupt the normal rhythm, originating from an irritable focus in the ventricular conduction system or muscle tissue

A

Premature Ventricular Complexes (PVCs)

83
Q

In PCVs, _______ inhibits conduction of a normally fired SA node impulse

A

Retrograde impulse

84
Q

Characteristics of PVCs

A

Rate depends on underlying rhythm

Irregular rhythm

P waves not related to QRS (if present at all)

Wide, bizarre QRS complexes with T waves in the opposite direction of the R wave

Absent PR intervals

Usually prolonged QT

85
Q

What are some possible causes of PVCs

A

MI and ischemia, enlargement of the ventricles, CHF, myocarditis

Use of certain drugs, particularly cocaine, amphetamines, TCAs, stimulants, PCP

Hypoxia, electrolyte imbalance, metabolic acidosis

86
Q

PVCs that look the same are called _______ and PVCs that look different from each other are called

A

Unifocal (uniform)

Multifocal (multiform)

87
Q

Like PACs, PVCs can be…

A

Bigeminal

Trigeminal

Quadrigeminal

88
Q

Two PVCs in a row are called…

A

A couplet

Indicate extremely irritable ventricles

89
Q

PVCs that fall between two regular complexes and do not disrupt the normal cardiac cycle are called…

A

Interpolated PVCs

90
Q

PVCs occurring on or near the previous T wave are called ______ and may precipitate __________

A

R-on-T PVCs

Ventricular tachycardia or fibrillation

91
Q

Slow dysrhythmia (20-40bpm) with wide QRS complexes that arise from the ventricles

A

Idioventricular rhythm

92
Q

Characteristics of idioventricular rhythm

A

20-40bpm

Regular rhythm

If present, p waves no related to QRS complex

Wide, bizarre QRS complex with T waves in the opposite direction of the R wave

Absent PR intervals

Prolonged QT

93
Q

Idioventricular rhythm that exceeds the inherent rate of the ventricles (40-100bpm)

A

Accelerated idioventricular rhythm

94
Q

Characteristics of accelerated idioventricular rhythm

A

40-100bpm

Regular

If present, p waves not related to QRS

Wide, bizarre QRS with T waves in the opposite direction of R wave

Absent PR interval

Prolonged QT

95
Q

Fast dysrhythmia (100-250bpm) that arises from the ventricles

A

Ventricular Tachycardia

96
Q

Ventricular Tachycardia is considered present when there are …

A

3 or more PVCs in a row

A brief episode may be called a “run” or “burst” or “salvo” of v. tach

May come in bursts of 6-10 complexes or may persist (sustained VT)

97
Q

Characteristics of Ventricular Tachycardia

A

100-250bpm

Regular rhythm

If present, p waves not related to QRS

Wide, bizarre QRS with T waves in the opposite direction of the R wave

Absent PR

Immeasurable QT

98
Q

Ventricular Tachycardia can occur with or without ______

A

Pulses

99
Q

_______ VT appears with each QRS complex similar in appearance

_______ VT appears with considerably variable QRS complexes

A

Monomorphic

Polymorphic

100
Q

What is Torsades de Pointes (TdP)?

A

A unique variant of polymorphic ventricular tachycardia

May be associated with prolonged QT interval

May be drug-induced or associated with electrolyte abnormalities

101
Q

How is Torsades de Pointes managed?

A

If in cardiac arrest - defibrillation

If patient not in cardiac arrest - infusion of MAGNESIUM SULFATE

Avoid bradycardia (worsens QT prolongation)

102
Q

Ventricular fibrillation results from….

A

Chaotic firing of multiple sites in the ventricles —> heart muscle quivers rather than contracting efficiently —> no effective muscular contraction —> no CO

103
Q

Patients with ventricular fibrillation will be …

A

In full cardiac arrest

Unresponsive

Pulseless

104
Q

Characteristics of ventricular fibrillation on ECG

A

300-500 ventricular unsynchronized impulses per minute

Totally chaotic rhythm

Absent P waves, PR interval, QT interval

QRS - wavy, chaotic line without any logic

105
Q

Most common cause of prehospital cardiac arrest in adults

A

Ventricular Fibrillation

106
Q

What happens if you don’t defibrillate a patient with ventricular fibrillation?

A

They fucking die

107
Q

Absence of any cardiac activity

A

Asystole

Appears as a flat (or nearly flat line)

Complete cessation of CO

108
Q

What is the prognosis for asystole?

A

😂😂😂😂

It’s a fucking terminal rhythm, dumbass

Chances of recovery are extremely low

Poor response to attempts at resuscitation

109
Q

Condition that has an organized electrical rhythm on the ECG monitor but patient is pulseless and apneic

A

Pulseless Electrical Activity (PEA)

Usually associated with severe underlying heart disease

110
Q

What are some reversible causes of PEA?

A 
Hypovolemia
Pericardial tamponade
Tension pneumothorax
Massive acute MI
Drug overdose
111
Q

Partial delays or complete interruptions in teh cardiac conduction pathway between the atria and ventricles

A

Heart block

Disrupts ventricular filling

112
Q

Common causes of heart blocks

A 
Ischemia
Myocardial necrosis
Degenerative disease of the conduction system
Congenital anomalies
Drugs (esp digitalis)
113
Q

What is a 1st-degree AV heart block?

A

Not a true block, but a consistent DELAY of conduction at teh level of the AV node

114
Q

Is a 1st degree AV heart block important?

A

Often of little or no clinical significance b/c all impulses are conducted to the ventricles

But can progress to higher degree block, esp in the presence of inferior wall MI

115
Q

Characteristics of 1st degree AV heart block

A

Underlying rate may be slow, normal, or reg

Underlying rhythm usually regular

P waves present and normal, precede QRS

QRS complexes normal

PR Interval >0.20 seconds and CONSTANT

QT WNL

116
Q

Intermittent block at the level of the AV node

A

2nd-Degree AV heart block Type I

Aka - “Wenckebach” or “Mobitz I”

117
Q

Characteristics of 2nd degree AV heart block

A

More P waves than QRS complexes and rhythm has patterned irregularity

PR interval progressively INCREASES until a QRS is dropped

After dropped beat, the next PR interval is shorter

As each subsequent impulse is generated, there is a progressively longer PR interval again until another QRS is dropped

CYCLE REPEATS!

118
Q

2nd-degree AV heart block Type I are usually …

A

Transient and reversible

May occur in otherwise health persons

May progress to more serious blocks (esp if it occurs in early MI)

119
Q

Intermittent block at the level of the bundle of His or bundle branches resulting in atrial impulses that are not conducted to the ventricles

A

2nd degree AV heart block Type II (“Mobitz II”)

120
Q

Characteristics of 2nd Degree AV heart block Type II

A

More P waves than QRS complexes

PR interval is PROLONGED and the duration remains CONSTANT

Intermittently, a P wave occurs and is not followed by a QRS complex (conduction is block)

121
Q

2nd-degree AV heart blocks type II more often progress to…

A

3rd degree (complete) heart block

122
Q

In 2nd degree av heart block type II, what type of rhythm will you observe?

A

If the conduction ratio remains the same, a regular rhythm

EXCEPT - if every other P wave is conducted, it is not possible to differentiate Mobitz I from Mobitz II (this is called a 2:1 AV Block**)

123
Q

A 2nd degree AV heart block type II is usually considered…

A

A serious dysrhythmia - “malignant”

Can result in decreased CO and may produce SSx of hypoperfusion

May progress to a more severe heart block or ventricular asystole

124
Q

Complete block of conduction at or below the AV node

A

3rd degree AV heart block

Impulses from atria cannot reach ventricles

AKA - complete heart block

125
Q

Characteristics of 3rd degree AV heart block

A

Upright and round P waves seem to “march right through the QRS complexes”

No associate between the P waves and QRS complexes

126
Q

Clinical significance of 3rd degree av heart blocks

A

Well tolerated as long as the escape rhythm is fast enough to generate a sufficient cardiac output to maintain adequate perfusion

Can result in decreased CO b/c of the asynchronous action of the atria/ventricles if the ventricular rate is slow

EKG Midterm (4 decks)

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