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Flashcards in Chapter 9 Deck (45):

Ventricular Dysrhythmias

Referred to as ventricular escape rhythms. Current is not traveling down the nol ventricular conduction pathway to activate both the R and L ventricles simultaneously, which causes delay to depolarize (contract) the ventricles. Indicated by a QRS measuring 0.12 seconds or longer.


Where are ventricle pacemaker cells found?

In the Purkinje fibers (the last natural pacemaker)


Nl rate in Purkinje fibers

20-40 bpm


Ventricular rhythms either occur as a result of:

1. Failure of the higher pacemaker sites within the heart or
2. The rate of automaticity from this portion of the heart is faster, and it takes over as the primary pacemaker within the heart


How to identify ventricular dysrhythmias

Missing P waves and "wide and bizarre" QRS complexes that measure 0.12 or greater


Premature Ventricle Complex (PVC)

Caused by an ectopic impulse that occurs early in the cycle and originates form the ventricles which causes excitability of the ventricular myocardium


What causes ectopic impulses?

By an ischemic region within the ventricles. Ischemia increases excitability of the ventricular myocardium.


Unifocal premature complex

Early complex (has similar shape, suggesting only one irritable focus present)


Multifocal premature complex

Varied shapes and forms of the PVCs


Interpolated PVC

PVC occurs during the normal R-R interval without interrupting the underlying rhythm


Occasional PVC

More than one to five PVCs per minute


Frequent PVC

Six or more PVCs per minute


Bigeminy PVC

Every other complex is a PVC


Trigeminy PVC

Every third complex is a PVC



Every fourth complex is PVC


R on T PVCs

PVC occurs on the downslope of the T wave or the vulnerable period of the ventricular refractory period


Coupling PVC

Two PVCs that occur back to back


PVC criteria for classification

Early QRS complex that measures 0.12 sec or greater and has a wide and bizarre appearance. There is no P wave


Signs and sx's of PVCs

Depend on their frequency and the amount of decrease in cardiac output that occurs with each. My be asymptomatic, others may complain of "thump or skipping" sensation with each PVC, dizziness and other low cardiac output sx's.


Tx for PVCs

Observation, oxygen, blood samples taken to evaluate hypoxic state as well as electrolyte values POTASSIUM AND CALCIUM


Agonal Rhythm

When all of te pacemakers in the heart have failed. This is the last semblance of ordered electrical activity in the heart. The only ventricular impulses are less than 20 bpm. Presents with "wide bizarre" QS complexes and an absence of P waves


Agonal rhythm criteria for classification

Has an absent P wave, a ventricular rae of less than 20 bpm, and wide and bizarre QRS complexes


Signs and sx's of agonal rhythm

Pt has a profound loss of cardiac output due to the loss of atril kick and slow ventricular rate. Pt will be unconscious


Tx for agonal rhythm

Basic life support and advanced cardiac life support intervention.


Idioventricular Rhythm

Occurs when the sinoatrial and junctional pacemakers fail to initiate an impulse and all that is remaining is the slow ventricular pacemaker. Presents with the classic "wide" QRS (0.12 or greater), a slow ventricular rate and an absence of P waves


Idioventricular rhythm criteria for classification

Absence of P waves, slow ventricular rate of 10-40 bpm, and wide and bizarre QRS complexes


Signs and sx's of idioventricular rhythm

Loss of cardiac output, pt will be unconscious


Tx for idioventricular rhythm

Cardiac medication and/or pacing


Accelerated idioventricular rhythm

Faster. Same as idioventricular rhythm and idioventricular dysrhythmias only with a faster fate. This dysrhythmia still presents with the classic "wide" QRS (0.12 second or greater) complex and an absence of P waves. The impulse rate is 40 -100 bpm


Accelerated idioventricular rhythm criteria for classification

Has an absence of P waves, a ventricular rate of 40-100 bpm, and wide and bizarre QRS complexes


Signs and sx's of accelerated idioventricular rhythm

Pt may or may no be able to tolerate this dysrhythmia due to the decrease of cardiac output, may or may not be unconscious


Tx for accelerated idioventricular rhythm

Pt may require medications and/or pacing


Ventricular Tachycardia

Occurs when three or more PVC's occur in a row and the ventricular rate is greater than 100 bpm, the ventricles are in continuous contraction-relaxation patten, and no period of delay exists between depolarization


Ventricular tachycardia criteria for classification

Has wide and bizarre QRS complexes with a classic "sawtooth" appearance, a rate in excess of 100 bpm and no P waves


Signs and sx's of ventricular tachycardia

Sx's of decreased cardiac output, may remain conscious or be unresponsive immediately (50% of ppl with no pulse or respiration)


Tx for ventricular tachycardia

Blue code when pt is unresponsive then CPR, may need defibrillator, medications, and intubation equipment. If responsive, medications and electrical treatments.


Ventricular Fibrillation

Chaotic asynchronous electrical activity within the ventricular tissue. Ventricle walls quiver, due to small isolated portions of the ventricles depolarizing. There is no classic, uniform depolarization causing a true contraction. This prevents any ejection of blood out of the ventricles, no cardiac output. The entire myocardium is quivering.


Ventricular fibrillation criteria for classification

Absence of organized electrical activity. The tracing is disorganized or chaotic in appearance.


Signs and sx's in ventricular fibrillation

Pt will be unresponsive, call Code blue, may lead to biological death, will always be unconscious, apneic (not breathing), and pulseless.


Tx for ventricular fibrillation

CPR, Advanced cardiac life support (ACLS) to regain nl cardiac function.


What is crash cart

A cart or try used during emergencies containing medication/equipment at site of medical/surgical emergency for life support



Absence of ventricular activity and depolarization. This is called "the straight or flat line"


Asystole criteria for classification

No waveform, no rate, no P waves, no PR interval, no QRS complexes


Signs and sx's of asystole

Pt will display no pulse, no cardiac outpu, unconsciousness, and apnea. Pt is in cardiac arrest


Tx for asystole

CPR and advanced cardiac life support