Chapter 6

Question 1

Premature Ventricular Complexes (PVC)

Answer 1

AKA premature ventricular extrasystole, ventricular premature beat, or premature ventricular depolarization

Rhythm: irregular; if the PVC is interpolated, PVC will be regular
Rate: normal range
P waves: absent, with retrograde conduction to the atria, may appear after QRS
PR interval: none because the ectopic beat originates in the ventricle
QRS duration: 0.12sec or more (wide)

Causes: acid base imbalance, acute coronary syndromes, digitalis toxicity, stimulants, normal variant, medications, ventricular aneurysm, hypoxia, heart failure, exercise, emotion stress

What to do about it: most do not require treatment, focusing on treatment of potentially reversible causes, ambulatory monitoring, beta blockers, calcium blockers

Question 2

Fusion beat

Answer 2

Result of an electrical impulse from a supraventricular site discharging at the same time as an ectopic site in the ventricles.

Because fusion beats result from both supraventricular and ventricular depolarization, these beats do not resemble normally conducted beats, nor do they resemble true ventricular beats

Three or more sequential PVCs are termed a run, a salvo or burst, and three or more PVCs that occur in a row at a rate of more than 100bpm is considered a run of VT

Question 3

Uniform and multiform premature ventricular complexes

Answer 3

PVCs that look alike in the same lead and begin from the same anatomical site are called uniform PVCs

PVCs that look different from one another in the same lead are called multiform PVCs

Question 4

Unifocal and Multiform

Answer 4

Unifocal - arise from the same anotomic site within the ventricles

Multiform - arise from different anotomic sites

Question 5

Unifocal and Multiform

Answer 5

Unifocal - arise from the same anotomic site within the ventricles

Multiform - arise from different anotomic sites

Question 6

Interpolated premature ventricular complexes

Answer 6

PVC occurs between two normally conducted QRS complexes without interfering with the normal cardiac cycle

Does not have a full compensatory pause; it is squeezed between two normally conducted QRS complexes (the R-R intervals between sinus beats remain the same) and does not disturb the next ventricular depolarization or SA node activity

Question 7

R on T premature ventricular complexes

Answer 7

R on T PVC occurs when the R wave of a PVC falls on the T wave of the preceding beat

Because ventricular depolarization is not yet complete during the last half of the T wave, it is possible that a PVC that occurs during this period will precipitate VT or VF

R on T phenomenon refers to the start of a ventricular tachydysrythmia because of an improperly timed electrical impulse on the T wave

Question 8

Ventricular escape beats or rhythms

Answer 8

Escape beats are late

Occurs after a pause in which a supraventricular pacemaker failed to fire

Protective mechanism safeguarding the heart from more extreme slowing or even asystole; because it is protective, you do not want to administer any medication that would wipe out the escape beat

Rhythm: irregular
Rate: normal
P waves: absent or with retrograde conduction to the atria
PR interval: none because VEB originate from the ventricles
QRS duration: 0.12sec or more (Wide)

Causes: acute coronary syndrome, digitalis toxicity, metabolic imbalance. SA node and AV junction fail to initiate electrical impulse

What to do about it: pulse oximeter, 12 lead ECG, atropine

Question 9

Idioventricular rhythm

Answer 9

Three or more ventricular escape beats occur in a row at a rate of 20 to 40bpm. QRS is wide

Rhythm: regular
Rate: 20 to 40bpm
P waves: absent or with retrograde conduction to the atria
PR interval: none
QRS: 0.12sec or greater (wide)

Question 10

Accelerated Idioventricular rhythm (AIVR)

Answer 10

Exist when three or more ventricular beats occur in a row at a rate of 41 to 100bpm

Rhythm: regular
Rate: 41 to 100bpm
P waves: absent or with retrograde conduction to the atria
PR interval: none
QRS duration: 0.12sec or more (wide)

Cause: acute MI, interventional coronary artery procedures. Acute myocarditis, cardiomyopathies, cocaine toxicity, digitalis toxicity, electrolyte imbalance, hypertensive heart disease, subarachnoid hemorrhage

What to do about it: generally does not require treatment. Symptomatic: apply pulse oximeter and administer oxygen, 12 lead ECG, IV access, stimulate SA node and improve AV conduction, atropine.

Question 11

Ventricular tachycardia (VT)

Answer 11

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

VT may occur with or without pulse

Occur as a short run that lasts less than 30sec

Question 12

Monomorphic ventricular tachycardia

Answer 12

When the QRS complexes of VT are of the same shape and amplitude

Also called ventricular flutter

Rhythm: regular
Rate: 101 to 250bpm
P waves: usually not seen

Causes: acid base imbalance, acute coronary syndromes, cocaine or methamphetamine abuse, electrolyte imbalance, structural heart disease, trauma, tricyclic antidepressant overdose

What to do about it: beta blocker, ambulatory monitoring or use of an implemented cardiac monitor may be ordered

Question 13

Polymorphic ventricular tachycardia (PMVT)

Answer 13

QRS complexes vary in shape and amplitude from beat to beat and appear to twist from upright to negative or negative to upright and back, resembling a spindle

Rhythm: regular or irregular
Rate: 150 to 300bpm
P waves: none
PR interval: none
QRS duration: 0.12 sec or more (wide)

Torsades de pointes (TdP)

Causes: long QT interval. QT interval may be congenital, acquired or idiopathic

What to do about it: different depending on the patient

Question 14

Ventricular Fibrillation

Answer 14

Chaotic rhythm that begins in the ventricles. No organized ventricular depolarization. Ventricular muscle quivers and there is no effective myocardial contraction and no pulse. No normal looking waveforms are visible.

Rhythm: rapid and chaotic with no patter or regularity
Rate: cannot be determined because there are no discernible waves or complexes to measure
P waves: none
PR interval: none
QRS duration: none

Cause: acute coronary syndromes, dysthymias, electrolyte imbalance, environmental factors, hypertrophy, increased sympathetic nervous system activity, proarrhythmic effect of anti arrhythmic and other medications, severe heart failure, structural heart failure, structural heart disease, vagal stimulation

What to do about it: patient in VF is unresponsive, apneic, and pulseless. CPR. Medication intervention.

Question 15

Defibrillation

Answer 15

The delivery of an electrical current across the heart muscle over a very brief period to terminate an abnormal rhythm

Unsynchronized countershock or asynchronous countershock because current delivery has no relationship to the cardiac cycle

Question 16

Automated external defibrillator

Answer 16

Sophisticated computer system that analyzes a patients heart rhythm using an algorithm to distinguish shockable rhythms from nonshockable rhythms and providing visual and auditory instruction to the rescuer to the deliver an electrical shock, if a shock is indicated

Question 17

Asystole (cardiac standstill)

Answer 17

Total absence of atrial and ventricular electrical activity. No atrial or ventricular rate or rhythm, no pulse, and no cardiac output. If atrial electrical activity is present, the rhythm is called P wave asystole or ventricular standstill

Rhythm: ventricular non discernible; atrial may be discernible
Rate: ventricular non discernible, but atrial activity may be observed
P waves: none
PR interval: none
QRS duration: absent

Cause: ventricular asystole may occur temporarily after the termination of a tachycardia with medications, defibrillation or synchronized cardioversion

What to do about it: confirm unresponsive patient and begin CPR

Question 18

Identify the ECG characteristics of an IVR
A. Essentially regular ventricular rhythm
B. Ventricular rate is 40 to 60bpm
C. QRS complexes measure 0.12 to 0.20sec or greater
D. P waves may occur before, during or after the QRS
E. Gradual alteration in the amplitude and direction of the QRS

Answer 18

A, C

The ECG characteristics of an Idioventricular rhythm include an essentially regular ventricular rhythm with QRS complex measuring 0.12 seconds or greater; P waves are usually absent or with retrograde conduction to the atria, may appear after the QRS (usually upright in the ST segment or T wave); an even curricular rate 20 to 40 bpm

Question 19

A 74 year old man experienced a syncopal episode at the grocery store. His blood pressure is 74/50mm HG, heart rate is 30bpm, and ventilators rate is 18 breaths/min. Breath sounds are clear, his oxygen saturation on room air is 97% and his blood glucose is normal. The cardiac monitor reveals a ventricular escape rhythm. Based on the information provided, which of the following are possible therapeutic interventions to consider?
A. Prepare for TCP
B. Establish IV access
C. Obtain a 12 lead ECG
D. Administer atropine IV
E. Administer amiodarone IV

Answer 19

A, B, C, D

Establish IV access and obtain a 12 lead ECG. Atropine may be ordered to treat the symptomatic bradycardia. TCP or a dopamine or epinephrine IV infusion may be ordered if atropine is ineffective. Ventricular antiarrhythmic medications (amiodarone, lidocaine, procainamide) should be avoided when managing patients with this rhythm. These drugs may abolish ventricular activity, possibly causing asystole

Question 20

How would you differentiate a junctional escape rhythm at 30bpm from an Idioventricular rhythm at the same rate?
A. It is impossible to differentiate a junctional escape rhythm from an Idioventricular rhythm
B. The junctional escape rhythm will have a narrow QRS complex; Idioventricular rhythm will have a wide QRS complex
C. The rate (I.e., 40bpm) would indicate a junctional escape rhythm, not an Idioventricular rhythm
D. The junctional escape rhythm will have a wide QRS complex; an Idioventricular rhythm will have a narrow QRS complex

Answer 20

B

A junctional escape rhythm has a narrow QRS complex and a intristic rate of 40 to 60 bpm. An Idioventricular rhythm has a wide QRS complex and in in intrinsic rate of 20 to 40 bpm

Question 21

The term for three or more PVCs occurring in a row at a rate of more than 100/min is:
A. Ventricular trigeminy
B. Ventricular fibrillation
C. A run of ventricular tachycardia
D. A run of ventricular escape beats

Answer 21

C

Three or more sequential PVCs our termed a run or burst, and three or more PVCs that occurred in a row at a rate of more than 100 bpm or considered a run of VT

Question 22

Which of the following are the priorities of care in cardiac arrest resulting from pulseless VT or VF?
A. Performing defibrillation
B. Performing high quality CPR
C. Inserting an advance airway
D. Giving resuscitation medications

Answer 22

A, B

The priorities of care and cardiac arrest, resulting from pulse less VT or VF our high-quality CPR and defibrillation. Other interventions, such as administering medication’s and inserting in advanced airway, are less important

Question 23

Select a shockable cardiac arrest rhythm from the choices below:
A. VF
B. PEA
C. Asystole
D. Pulseless VT

Answer 23

A, D

VF and pulseless VT our shockable rhythms which means that delivering a shock to the heart with a defibrillator may result in termination of the rhythm. Asystole and PEA are non-shockable rhythms.

Question 24

The primary difference between a PVC and a ventricular escape beat is:
A. A PVC is early and an escape beat is late
B. A PVC has a narrow QRS and a ventricular escape beat has a wide QRS
C. The ventricular rate associated with escape beat is faster than that of a PVCs
D. The ventricular rhythm with a PVC is irregular, but if it is regular with an escape beat

Answer 24

A

A PVC occurs before and a ventricular escape beat occurs after the next expected beat of the underlying rhythm

Question 25

Which of the following statements are true about asystole?
A. Begin TCP as soon as the equipment is available
B. Defibrillation is the treatment of choice for this rhythm
C, use the Hs and Ts when considering possible reversible causes of the rhythm
D. If a flat line is present but atrial activity is seen, the rhythm is called P wave asystole or ventricular standstill

Answer 25

C, D

The fibrillation is performed to briefly stun the heart with electrical current of sufficient intensity to allow the hearts natural pacemakers to resume normal activity. With asystole, there is no electrical activity to reset. Similarly, TCP is not indicated. Instead, focus your efforts on performing high-quality CPR, establishing IV access, giving epinephrine, and using the Hs and Ts to identify possible reversible causes of event. Asystole also called cardiac standstill because there is a total absence of atrial and ventricular electrical activity. if a flatline is present and true activity is seen (P waves are present) The rhythm is called P-wave asystole or ventricular standstill

Question 26

An 83 year old woman with a history of ischemic heart disease presents with a sudden onset of sustained monomorphic VT. Which o the following should be anticipated when caring for this patient?
A. Stroke
B. Syncope
C. Heart failure
D. Hypotension
E. Circulatory collapse

Answer 26

B, C, D, E

The rapid heart rate associated with sustained VT can cause a marked decrease in ventricular function and cardiac output, particularly inpatient with underlying health disease, resulting in acute heart failure, syncope, hypertension, or circulatory collapse within several seconds to minutes after the onset of VT

Question 27

Antiarrhythmics can cause a __________ effect, which means that they can have the potential to cause serious adverse effects, more serious dyshythmias, or both, than those that they are intended to treat.
A. Probiotic
B. Proactive
C. Polymorphic
D. Proarrhythmic

Answer 27

D

Antiarrhythmics can cause a pro arrhythmic effect, which means that they have the potential to cause serious adverse effects, more serious dysrhythmias, or both, then those that they were intended to treat

Question 28

Which of the following is a type of PVC that occurs between two normally conducted QRS complexes and does not disturb the next ventricular depolarization or SA node activity?
A. A fusion beat
B. A uniform PVC
C. An escape beat
D. An interpolated PVC

Answer 28

D

An interpolated PVC occurs between two normally conducted QRS complexes and does not disturb the next ventricular depolarization or SA node activity

Question 29

The ECG characteristics of monomorphic VT include:
A. A PR interval of 0.12 to 0.20sec
B. A ventricular rate of 101 to 250bpm
C. A ventricular rhythm that is essentially regular
D. A QRS that is 0.12sec or greater in duration

Answer 29

B, C, D

ECG characteristics of monomorphic VT include a ventricular rhythm that is essentially regular, a ventricular rate of 101 to 250 bpm, and a QRS that is 0.12 seconds or greater in duration. There is no PR interval associated with VT because the rhythm originates below the AV node