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54 Cards in this Set
- Front
- Back
rhythm disturbances arising below the AV node
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ventricular arrhythmias
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the most common of all ventricular arrhythmias
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premature ventricular contractions
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characterized by a wide and bizarre QRS complex
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ventricular beats
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True or False:
A retrograde P wave may be seen with PVCs. |
True, but not usually.
It is more common to see no P waves. |
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A PVC is usually followed by a ______.
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prolonged pause
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True or False:
PVC's are common in normal hearts and rarely require treatment. |
True.
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True or False:
An isolated PVC in the setting of an AMI is not necessarily cause for concern. |
False.
An isolated PVC in the setting of an AMI is an ominous sign because it can trigger a life threatening arrhythmia. |
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alternating rhythm in which one normal sinus beat is followed by one PVC in a regular pattern
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ventricular bigeminy
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alternating rhythm in which two normal sinus beats are followed by one PVC in a regular pattern
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ventricular trigeminy
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Name the set of standards used to determine when one should worry about PVCs.
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the rules of malignancy
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List the five Rules of Malignancy for identifying situations in which PVCs pose an increased risk.
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"Fred Called My Red Head."
(1) Frequent (2) Consecutive (3) Multiform (4) R-on-T (5) Heart problem/AMI |
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term for a run of three or more consecutive PVCs
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ventricular tachycardia (VT)
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usual rate of ventricular tachycardia
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100 to 200 beats per minute
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True or False:
Unlike PSVT, ventricular tachycardia may be slightly irregular. |
True.
But it may take a very fine eye to see this. |
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True or False:
Sustained VT with a pulse is a relatively stable rhythm. |
False.
Sustained VT is an emergency, presaging cardiac arrest and requiring immediate treatment. |
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In terms of morphology, VT may be ______ or ______.
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uniform
polymorphic |
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What condition is polymorphic VT commonly associated with?
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acute myocardial ischemia/infarction
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What condition is uniform VT commonly associated with?
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Healed infarctions
(scarred myocardium provides substrate for reentrant VT) |
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chaotic, pulseless, preterminal rhythm seen almost solely in dying hearts
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ventricular fibrillation
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most frequently encountered rhythm in adults who experience sudden death
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ventricular fibrillation
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benign ventricular rhythm that is sometimes seen during acute myocardial infarctions
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accelerated idioventricular rhythm
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True or False:
Accelerated idioventricular is an irregular rhythm. |
False.
It is regular. |
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What is the usual rate of an accelerated idioventricular rhythm?
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50 to 100 beats per minute
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Ventricular rhythm often characterized by an escape focus that has accelerated to drive the heart
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accelerated idioventricular rhythm
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ventricular rhythm with a rate of less than 50
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idioventricular rhythm
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a unique form of V-tach usually seen in patients with prolonged QT intervals
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Torsades de Pointes
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"twisting of the points" form of V-tach
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Torsades de Pointes
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four causes of prolonged QT interval
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congenital origin
electrolyte disturbances acute myocardial infarction pharmocological agents |
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What are some specific electolyte imbalances that may cause a prolonged QT interval?
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hypocalcemia
hypomagnesemia hypokalemia |
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What are six pharmocological agents that may cause a prolonged QT interval?
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antiarrhythmics
tricyclic antidepressants phenothiazines antifungals antihistamine/antibiotic combos erythromycin and quinolones |
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What specific electrical event generally results in a prolonged QT interval?
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prolonged ventricular repolarization
(lengthened T wave) |
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Name a rhythm that may result from a PVC falling on an elongated T wave in a rhythm with prolonged QT intervals.
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Torsades de Pointes
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True or False:
In the clinical setting, Torsades de Pointes is indistinguishable from standard V-Tach and is treated in exactly the same way. |
False.
It is important to distinguish Torsades de Points from standard VT, because they are treated very differently. |
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True or False:
The prognosis for ventricular arrhythmias is far more ominous than it would be for supraventricular arrhythmias. |
True.
Therefore, it is important to be able to distinguish the difference. |
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In most cases, what is the key difference between supraventricular and ventricular arrhythmias?
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the QRS width
narrow QRS = supraventricular wide QRS = ventricular |
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What is the one circumstance that may cause a supraventricular rhythm to look like ventricular rhythm?
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when a supraventricular beat is conducted aberrantly through the ventricles
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True or False:
An aberrantly conducted supraventricular beat may be indistinguishable from a ventricular beat. |
True.
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What type of beat often precipitates an aberrantly conducted supraventricular beat?
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atrial premature beats
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What ventricular conduction situation may by present in cases of premature atrial contractions that occur very early?
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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
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Name the two possible causes of a wide QRS complex.
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(1) ventricular beat
(2) supraventricular beat conducted aberrantly |
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How can you tell a single aberrantly conducted atrial beat from a ventricular beat?
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Only in the case of the atrial beat will a P-wave precede the wide QRS complex, possibly buried within a preceding T wave.
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What two clinical clues may help tell a sustained aberrantly conducted supraventricular rhythm from a sustained ventricular rhythm?
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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) |
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What three electrocardiographic clues may help tell a sustained aberrantly conducted supraventricular rhythm from a sustained ventricular rhythm?
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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. |
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True or False:
On EKG, it may be impossible to tell the difference between VT and an aberrantly conducted PSVT. |
True.
The distinction can be difficult or impossible to make. |
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The Ashman phenomenon is commonly seen in patients with what arrhythmia?
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atrial fibrillation
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Condition characterized by a wide, aberrantly conducted supraventricular beat occurring after a QRS complex that is preceded by a long pause
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the Ashman phenomenon
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Describe what causes the Ashman phenomenon.
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refractory bundle branches due to a lengthy pause after the preceding beat
(bundle branches tend to repolarize much more slowly following a delayed beat) |
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Why is the Ashman phenomenon common during A-fib?
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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 |
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True or False:
A narrow QRS complex virtually always implies a supraventricular rhythm. |
True.
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Invasive procedure in which the exact source of an arrhythmia can be mapped to determine the most appropriate therapy.
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Programmed Electrical Stimulation
(aka: Electrophysiologic Studies or "EPS") |
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surgical procedure that intentionally damages a reentrant pathway to cure an arrhythmia
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catheder ablation
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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
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implantable cardioverter-defibrillator
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small portable devices that require minimal training and are capable of detecting and correcting ventricular fibrillation in collapsed individuals
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automatic external defibrillators (AED)
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An aberrant-looking beat that occurs at the regular R-R interval may be a ______.
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fusion beat
(capture beat) |