Ventricular Rhythms Flashcards
What is a PVC?`
ectopic beat originating in the ventricles
Is there a P wave with a PVC?
NO
Wide or narrow QRS with PVC?
wide
T wave description with PVC?
T wave will be the opposite direction of the QRS complex
What is the difference in ventricular bigeminy and ventricular trigeminy?
bigeminy is a PVC that occurs every other sinus impulse
trigeminy is a PVC that occurs after two sinus impulses
What is the difference between uniform and multiformed PVCs? which are worse?
uniform come the the same site and have the smae form while multiformed come from multiple sites and have different forms
multiformed are worse becuase it means more sites are irritated increasing the chances of coverting to a dangerous rhythm
What is the differnce between a couplet and triplet?
a couplet is two PVCs in a row and a triplet is 3 in a row and is considered a short run of v-tach
Do PVCs occur in healthy people?
Yes, they are the most common of all ectopic beats
also can occur with presence of heart disease and myocardial irritability
Because PVCs may be a sign of myocardial irritability in the ventricles, what can it they be a precursor to?
v-tach or v-fib
what is the r-on-t phenomenon? Is this significant?
ventricles depolarize (R wave) again during the repolarization process (T wave)
It is significant because it may cause VF or sudden death
How are PVCs treated?
infrequent and isolated PVCs require no treatment
repeated PVCs may be treated with antiarrhythmic agents, IV antiarrhythmics for emergency situations
potassium supplementation for possible hypokalemic cause
cessation of digoxin therapy if suspected toxicity
Define ventricular tachycardia.
three or more PVCs in a row is considered v-tach.
QRS with VT?
wide and bizarre, occurring fairly regularly with a minimum of 100 bpm
P waves with VT?
Nope, not usually. unrelated to QRS if appearing.
Can VT be short and nonsustained or long and sustained?
YES YES YES
When can VT commonly occur?
MI
Other causes of VT?
same as PVC
what can VT lead to?
VF or hemodynamic compromise if rate is fast enough and sustained long enough
If stable and wanting to convert from VT, what is the first-line therapy?
IV lidocaine
If the patient becomes unstable while in VT, what is the next therapy used?
synchronized cardioversion
If the unstable patient in VT still hasn’t converted and the situation becomes emergent, what is the next line of therapy?
an unsynchronized defibrillation may be indicated by this point
what are some long-term treatments for VT?
ICD (implantable cardioverter defibrillator)
What is torsades de pointes?
This is a type of VT where QRS complexes go from positive to negative or negative to positive
QRS of torsades de pointes?
large, bizarre, polymorphous or multiformed of varying amplitude and direction. These vary from beat to beat and appear to be twisting around the isoelectric line
What is the rate of torsades de pointes?
100-180 BPM usually… can reach 200-300
When is torsades de pointes most likely to occur?
whenever the QT interval is prolonged
What are some things that can prolong the QT interval?
severe bradycardia
Drugs - 1A antiarrhythmics
electrolyte disturbances - hypoK hypoCa hypoMg
What are some treatment modalities for torsades de pointes?
focused on shortening the QT interval
Drug therapy - mag, isoproterenol
override pacing
discontinuing agents causing rhythm
correcting electrolyte imbalances
If it does not revert by itself to sinus, emergency cardioversion or defibrillation may be necessary
What is the definition of v-fib?
rapid, irregular and noneffective depolarizations of the ventricle
QRS in VF?
NOT DEFINEABLE
When is VF seen?
myocardial ischemia and MI
catheter manipulation in ventricles
electrocution
prolonged QT interval
anything that causes circulatory failure
Treatment for VF?
defibrillation
CPR
Drugs (if defibrillation doesnt produce response)
ICD for long-term management
What is an AIVR?
Accelerated idioventricular rhythm - this is a wide QRS tachycardia that is caused by the acceleration of the rate of the ventricular pacemaker cells, beating as fast as 50-100 BPM.
when is an AIVR typically seen?
acute MI after thrombolytic therapy to resume coronary perfusion
less commonly from ischemia or digoxin toxicity
How is AIVR treated?
Often treatment is not necessary, deterioration to rapid VT is rare.
If hemodynamically compromised atropine may increase sinus rate, or atrial pacing.
