Ekg - Ventricular Arrhythmias

Front 1

rhythm disturbances arising below the AV node

Back 1

ventricular arrhythmias

Front 2

the most common of all ventricular arrhythmias

Back 2

premature ventricular contractions

Front 3

characterized by a wide and bizarre QRS complex

Back 3

ventricular beats

Front 4

True or False:
A retrograde P wave may be seen with PVCs.

Back 4

True, but not usually.
It is more common to see no P waves.

Front 5

A PVC is usually followed by a ______.

Back 5

prolonged pause

Front 6

True or False:
PVC's are common in normal hearts and rarely require treatment.

Back 6

True.

Front 7

True or False:
An isolated PVC in the setting of an AMI is not necessarily cause for concern.

Back 7

False.
An isolated PVC in the setting of an AMI is an ominous sign because it can trigger a life threatening arrhythmia.

Front 8

alternating rhythm in which one normal sinus beat is followed by one PVC in a regular pattern

Back 8

ventricular bigeminy

Front 9

alternating rhythm in which two normal sinus beats are followed by one PVC in a regular pattern

Back 9

ventricular trigeminy

Front 10

Name the set of standards used to determine when one should worry about PVCs.

Back 10

the rules of malignancy

Front 11

List the five Rules of Malignancy for identifying situations in which PVCs pose an increased risk.

Back 11

"Fred Called My Red Head."

(1) Frequent
(2) Consecutive
(3) Multiform
(4) R-on-T
(5) Heart problem/AMI

Front 12

term for a run of three or more consecutive PVCs

Back 12

ventricular tachycardia (VT)

Front 13

usual rate of ventricular tachycardia

Back 13

100 to 200 beats per minute

Front 14

True or False:
Unlike PSVT, ventricular tachycardia may be slightly irregular.

Back 14

True.
But it may take a very fine eye to see this.

Front 15

True or False:
Sustained VT with a pulse is a relatively stable rhythm.

Back 15

False.
Sustained VT is an emergency, presaging cardiac arrest and requiring immediate treatment.

Front 16

In terms of morphology, VT may be ______ or ______.

Back 16

uniform

polymorphic

Front 17

What condition is polymorphic VT commonly associated with?

Back 17

acute myocardial ischemia/infarction

Front 18

What condition is uniform VT commonly associated with?

Back 18

Healed infarctions
(scarred myocardium provides substrate for reentrant VT)

Front 19

chaotic, pulseless, preterminal rhythm seen almost solely in dying hearts

Back 19

ventricular fibrillation

Front 20

most frequently encountered rhythm in adults who experience sudden death

Back 20

ventricular fibrillation

Front 21

benign ventricular rhythm that is sometimes seen during acute myocardial infarctions

Back 21

accelerated idioventricular rhythm

Front 22

True or False:
Accelerated idioventricular is an irregular rhythm.

Back 22

False.
It is regular.

Front 23

What is the usual rate of an accelerated idioventricular rhythm?

Back 23

50 to 100 beats per minute

Front 24

Ventricular rhythm often characterized by an escape focus that has accelerated to drive the heart

Back 24

accelerated idioventricular rhythm

Front 25

ventricular rhythm with a rate of less than 50

Back 25

idioventricular rhythm

Front 26

a unique form of V-tach usually seen in patients with prolonged QT intervals

Back 26

Torsades de Pointes

Front 27

"twisting of the points" form of V-tach

Back 27

Torsades de Pointes

Front 28

four causes of prolonged QT interval

Back 28

congenital origin
electrolyte disturbances
acute myocardial infarction
pharmocological agents

Front 29

What are some specific electolyte imbalances that may cause a prolonged QT interval?

Back 29

hypocalcemia
hypomagnesemia
hypokalemia

Front 30

What are six pharmocological agents that may cause a prolonged QT interval?

Back 30

antiarrhythmics
tricyclic antidepressants
phenothiazines
antifungals
antihistamine/antibiotic combos
erythromycin and quinolones

Front 31

What specific electrical event generally results in a prolonged QT interval?

Back 31

prolonged ventricular repolarization
(lengthened T wave)

Front 32

Name a rhythm that may result from a PVC falling on an elongated T wave in a rhythm with prolonged QT intervals.

Back 32

Torsades de Pointes

Front 33

True or False:
In the clinical setting, Torsades de Pointes is indistinguishable from standard V-Tach and is treated in exactly the same way.

Back 33

False.
It is important to distinguish Torsades de Points from standard VT, because they are treated very differently.

Front 34

True or False:
The prognosis for ventricular arrhythmias is far more ominous than it would be for supraventricular arrhythmias.

Back 34

True.
Therefore, it is important to be able to distinguish the difference.

Front 35

In most cases, what is the key difference between supraventricular and ventricular arrhythmias?

Back 35

the QRS width

narrow QRS = supraventricular
wide QRS = ventricular

Front 36

What is the one circumstance that may cause a supraventricular rhythm to look like ventricular rhythm?

Back 36

when a supraventricular beat is conducted aberrantly through the ventricles

Front 37

True or False:
An aberrantly conducted supraventricular beat may be indistinguishable from a ventricular beat.

Back 37

True.

Front 38

What type of beat often precipitates an aberrantly conducted supraventricular beat?

Back 38

atrial premature beats

Front 39

What ventricular conduction situation may by present in cases of premature atrial contractions that occur very early?

Back 39

The right bundle branch has a tendency to sluggishly repolarize at the Purkinje fibers, so a very early PAC may find half of the ventricular conduction system refractory and unable to depolarize, causing the beat to be aberrantly conducted through the ventricles

Front 40

Name the two possible causes of a wide QRS complex.

Back 40

(1) ventricular beat
(2) supraventricular beat conducted aberrantly

Front 41

How can you tell a single aberrantly conducted atrial beat from a ventricular beat?

Back 41

Only in the case of the atrial beat will a P-wave precede the wide QRS complex, possibly buried within a preceding T wave.

Front 42

What two clinical clues may help tell a sustained aberrantly conducted supraventricular rhythm from a sustained ventricular rhythm?

Back 42

CAROTID MASSAGE
Carotid massage may terminate PSVT but not VT

P-WAVES/CANNON A-WAVES
More that 75% of VT are accompanied by AV dissociation. Although the QRS complexes usually hide the underlying P-waves, Cannon A Waves may be detectible in VT (whereas they would not be present in PSVT)

Front 43

What three electrocardiographic clues may help tell a sustained aberrantly conducted supraventricular rhythm from a sustained ventricular rhythm?

Back 43

P-WAVES
AV dissociation P-waves can sometimes be seen on EKG in cases of VT, whereas PSVT will typically show retrograde P-waves, if any. On very rare occasions, VT may also produce retrograde P-waves, but this is not normally the case.

FUSION BEATS
Fusion beats (or capture beats) may be seen in VT only, as they result from a normally conducted supraventricular impulse that was allowed to slip through the AV juntion to collide with a simultaneous ventricular beat.

INITIAL QRS DEFLECTION
In aberrant PSVT, the initial QRS deflection is typically in the same direction of the normal QRS; in VT, the initial deflection is often in the opposite direction.

Front 44

True or False:
On EKG, it may be impossible to tell the difference between VT and an aberrantly conducted PSVT.

Back 44

True.
The distinction can be difficult or impossible to make.

Front 45

The Ashman phenomenon is commonly seen in patients with what arrhythmia?

Back 45

atrial fibrillation

Front 46

Condition characterized by a wide, aberrantly conducted supraventricular beat occurring after a QRS complex that is preceded by a long pause

Back 46

the Ashman phenomenon

Front 47

Describe what causes the Ashman phenomenon.

Back 47

refractory bundle branches due to a lengthy pause after the preceding beat

(bundle branches tend to repolarize much more slowly following a delayed beat)

Front 48

Why is the Ashman phenomenon common during A-fib?

Back 48

The irregularly timed ventricular responses typical of A-fib sets the stage for:

(1) short beats followed by long beats

(2) delayed repolarization of the bundle branches following the short/long beat sequence

(3) premature beats aberrantly conducted during the relative refractory period of the bundle branches

Front 49

True or False:
A narrow QRS complex virtually always implies a supraventricular rhythm.

Back 49

True.

Front 50

Invasive procedure in which the exact source of an arrhythmia can be mapped to determine the most appropriate therapy.

Back 50

Programmed Electrical Stimulation

(aka: Electrophysiologic Studies or "EPS")

Front 51

surgical procedure that intentionally damages a reentrant pathway to cure an arrhythmia

Back 51

catheder ablation

Front 52

small device implanted under the skin below the shoulder that monitors and corrects dangerous arrhythmias with a shock to the right ventricle through an implanted electrode

Back 52

implantable cardioverter-defibrillator

Front 53

small portable devices that require minimal training and are capable of detecting and correcting ventricular fibrillation in collapsed individuals

Back 53

automatic external defibrillators (AED)

Front 54

An aberrant-looking beat that occurs at the regular R-R interval may be a ______.

Back 54

fusion beat

(capture beat)