Flashcards in Chapter 9 Deck (45):
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
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
PVC occurs during the normal R-R interval without interrupting the underlying rhythm
More than one to five PVCs per minute
Six or more PVCs per minute
Every other complex is a 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
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
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.
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
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.
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