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76 Cards in this Set

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term for arrhythmias that originate in the atria or the AV node
supraventricular arrhythmias
single ectopic supraventricular beats that originate in the atria
atrial premature beats

(premature atrial contractions or PACs)
single ectopic supraventricular beats that originate in the vicinity of the AV node
junctional premature beats

(premature junctional contractions or PJCs)
True or False:
Premature atrial and junctional beats generally indicate underlying cardiac disease.
False.
Premature atrial and junctional beats are common phenomena that neither indicate underlying disease nor require treatment.
True or False:
Premature atrial and junctional beats can initiate more sustained arrhythmias.
True.
What are two ways an atrial premature beat can be distinguished from a normal sinus beat.
contour of P-wave and timing
True or False:
Sinus P-waves and Atrial P-waves are essentially of the same morphology.
False.
When atrial depolarization does not occur in the normal matter, the configuration of the resultant P-wave differs from a normal sinus wave.
If the site of origin of an atrial beat is far from the sinus node, what prominent EKG finding would you expect to find?
atrial axis deviation
True or False:
An atrial premature beat comes too early, intruding itself before the next anticipated sinus wave.
True.
abnormal p-waves sometimes seen in junctional premature beats
retrograde P-waves
What is the usual configuration of P-waves in most junctional beats?
Invisible. Most junctional beats do not have detectible P-waves; a few have visible retrograde P-waves.
What is the difference between a junctional escape beat and a junctional premature beat?
Timing.
The escape beat occurs after a long pause;
the premature beat occurs early (prematurely).
True or False:
Both atrial and junctional premature beats result in wide QRS complexes.
False.
Atrial and junctional premature beats are usually conducted normally through the ventricles.
What are the five types of sustained supraventricular arrhythmias?
(1) Paroxysmal Supraventricular Tachycardia (PSVT)
aka: AV Nodal Tachycardia

(2) Atrial Flutter

(3) Atrial Fibrillation

(4) Multifocal Atrial Tachycardia (MAT)

(5) Paroxysmal Atrial Tachycardia (PAT)
aka: Ectopic Atrial Tachycardia
Name a very common supraventricular arrythmia of sudden onset, usually initiated by a premature atrial or junctional beat, that often terminates as abruptly as it started.
PSVT
What is meant by Paroxysmal?
Sudden (or violent) onset
True or False:
PSVT can occur in perfectly normal, disease-free hearts as a result of alcohol, coffee, or sheer excitement.
True.
Is PSVT regular or irregular?
PSVT is an absolutely regular rhythm.
What is the usual rate of PSVT?
between 150 and 250 beats per minute
What is the most common form of PSVT driven by?
reentrant circuit looping within the AV node
True or False:
All PSVTs are essentially from exactly the same source.
False.
There are several types of PSVT.
True or False:
PSVT may produce retrograde P waves.
True.
If retrograde P-waves were present in PSVT, in which leads would you expect to see them?
Leads II or III,
"psuedo R-prime" in V1
What is a psuedo R-prime?
a little blip in the QRS complex that represents a superimposed P wave
True or False:
In most cases of PSVT, P-waves are readily seen.
False.
In most cases of PSVT, P waves are so buried in the QRS complexes that they cannot be identified with any confidence.
Would you typically expect to see a wide or narrow QRS complex in cases of PSVT?
narrow
What is the purpose of the carotid massage?
It is typically used to help diagnose or terminate an episode of PSVT.
receptors located at the angle of the jaw at the carotid bifurcation that sense changes in blood pressure
baroreceptors
How do baroreceptors regulate cardiac output?
When a rise in pressure is detected, reflex responses are sent from the brain along the vagus nerve to the heart.
What two effects does vagal input have on the heart?
(1) slows conduction through the AV node (very important)

(2) decreases sinus rate
How can baroreceptors be fooled into thinking that blood pressure is rising?
gentle pressure applied externally to the carotid artery
Why does the bearing down or squatting tend to slow cardiac function?
Both maneuvers cause a temporary rise in blood pressure that stimulates vagal input to the heart.
Which is the simplest and most widely used maneuver for stimulating vagal input to the heart?
carotid massage
Why is carotid massage particularly effective on PSVT?
Carotid massage slows conduction through the AV node. In most cases, the underlying mechanism of PSVT is a reentrant circuit in the AV node.
What two effects might carotid massage have on PSVT?
(1) Interrupt the reentrant circuit and thereby terminate the arrhythmia

(2) At the very least, slow the arrhythmia so that the presence or absence of P waves can be more easily determined and the arrhythmia diagnosed
True or False:
Carotid massage may induce sinus arrest.
True.
Always have a rhythm strip running as well as equipment for resuscitation on standby.
True or False:
Atrial Flutter is more common than PSVT.
False.
Atrial Flutter is less common than PSVT.
What is the typical rate of P waves in atrial flutter?
250 to 350 beats per minute
What is atrial flutter generated by in its most common form?
a reentrant circuit around the annulus of the tricuspid valve
the rising and falling baseline waves associated with atrial flutter
flutter waves
(saw-toothed pattern)
In which leads is the saw-toothed pattern commonly associated with atrial flutter most likely to be clearly visible?
Leads II and III
Why aren't all atrial flutter waves allowed to proceed through the AV node?
The AV node does not have sufficient time to repolarize between each wave
phenomenon in A-flutter characterized by intermittent depolarization of the AV node by flutter waves
AV block
Most common AV block ratio in Atrial Flutter?
2:1 is most common

(3:1 and 4:1 also frequently seen)
True or False:
Carotid massage is effective for terminating Atrial Flutter.
False.
Because atrial flutter originates above the AV node, carotid massage will not result in termination of the rhythm.
Rhythm characterized by chaotic atrial activity and AV nodal bombardment of more than 500 atrial impulses per minute.
atrial fibrillation
Describe baseline appearance in atrial fibrillation.
flat or slightly undulating,
no true P waves visible
True or False:
In atrial fib, the AV node regularly responds to atrial impulses.
False.
The AV node, faced with an extraordinary blitz of atrial impulses, allows only occasional impulses to pass through at irregular intervals.
How would the regularity of the ventricular rhythm in atrial fibrillation be characterized?
"irregularly irregular"
Most commonly, the ventricular rate of atrial fibrillation falls within this range.
120 to 180 beats per minute
(however slower and faster rates are often seen)
What is the key to identifying atrial fibrillation.
irregularly irregular QRS complexes
in the absence of discrete P waves
wavelike forms often seen on close inspection of atrial fib baseline
fibrillation waves
Describe the effect of carotid massage on atrial fibrillation.
may slow the ventricular rate, but it is rarely used because the diagnosis of a-fib is usually obvious
True or False:
A-flutter is more common that A-fib.
False.
A-fib is much more common than A-flutter.
True or False:
Atrial fib does not generally reflect any underlying cardiac pathology.
False.
Underlying cardiac pathology is often present, especially mitral valve disease or coronary artery disease. (Differential diagnosis include hyperthyroidism, pulmonary emboli, and pericarditis.)
True or False:
Multifocal Atrial Tachycardia is an irregular rhythm.
True.
What is the usual rate seen in Multifocal Atrial Tachycardia?
100 to 200 beats per minute
Define the probable source of MAT.
random firing of several different ectopic atrial foci
Which type of disease is most commonly associated with MAT?
Severe lung disease
What is the most frequently required treatment for MAT?
MAT rarely requires any treatment.
What is the effect of carotid massage on MAT?
Carotid massage has no effect on MAT.
Name the rhythm that is similar to MAT, but with a rate of less than 100 beats per minute.
wandering atrial pacemaker
True or False:
A wandering atrial pacemaker can be seen in normal, healthy hearts.
True.
How is MAT distinguished from atrial fibrillation?
MAT is characterized by easily identifiable, variable contour P waves occuring before each QRS complex.
True or False:
In MAT, the intervals between different P waves and the QRS complex generally remains constant.
False.
The intervals are variable.
What is a necessary finding to diagnose MAT?
at least three different P wave morphologies
True or False:
Paroxysmal Atrial Tachycardia is an irregular rhythm.
False.
PAT is regular.
What is the usual rate for PAT?
100 to 200 beats per minute
What are to two possible origins of a PAT rhythm?
(1) enhanced automaticity of an ectopic atrial focus

(2) reentrant circuit within the atria
Of the automatic and reentry forms of PAT, which form is more common?
Automatic.
(increased automaticity of an ectopic focus)
What are the typical signs of automatic type PAT?
"warm-up period" start-up, characterized by rhythm irregularity during this period; similar "cool-down period" upon termination

PAT itself is regular when sustained.
What are the typical signs of reentrant type PAT?
abrupt startup with an atrial premature beat
What is another term used for reentrant type PAT?
atypical atrial flutter
What is the most common underlying cause of PAT?
digitalis toxicity
How can you tell PAT from PSVT?
Many times you can't. However, look for a warm-up or cool-down period. Carotid massage can also be helful, as it will generally terminate PSVT but not PAT.
What is the effect of carotid massage on PAT.
Carotid massage has no effect on PAT.