ventricular arrhythmias Flashcards
premature ventricular contraction
premature firing of a ventricular cell
- initiated by purkinje fibers
- causes ventricles to be in a refractory state-so when the normal pacers fire, the ventricles won’t contract at the normal time
what is a compensatory pause>
pause- pause in the heart beat following an extrasystole that is long enough to compensate for the prematurity of the extrasystole
*seen in PVC so the next beat will arrive on time
what are some features of PVCs
Often benign
Frequent PVCs can depress ventricular function
Precursor to ischemia or structural disease
Substantial day to day variation
Affected by stress, medications, caffeine
sx of PVC
palpitations, dizzy, strong Heart beat, pause
what is something to look for during a stress test? (what happens to PVC?)
want PVC to go away- if they increase it may indicate ischemia
EKG findings on a PVC
Rate: Depends on underlying rhythm
Rhythm: Irregular
P wave: Not present on PVC
P:QRS ratio: No P waves on the PVC
PR interval: None
QRS: Wide >0.12 seconds
Grouping: Bigeminy, Trigeminy possible
classifying PVC: 1?
PVC
classifying PCV: 2 in a row?
couplet
classifing PCS: 3 + in a row but lasting less than 30 sec
nonsustained ventricular tachycardia (Vtach)
patter of PVCs: every other beat?
bigeminy
pattern of PVCs: every 3rd beat
trigeminy
ventricular escape beate
occurs when SA node fails to fire and next available pacemaker cell is in the ventricle
what happens to the normal rhythm in a ventricular escape beat?
origianl pacemaker doesn’t fire, so the next beat doesn’t arrive on time
*noncompensatory pause
sx of ventricular escape beat
paplitations, dizzy, presycope, syncope
tx of ventricular escape beat?
electrolye corrections, pacemaker if become rhythm
EKG findings in ventricular escape beat
Rate: Depends on underlying rhythm
Rhythm: Irregular
P wave: Not present on PVC
P:QRS ration: No P waves on the PVC
PR interval: None
QRS: Wide >0.12 seconds
Grouping: None
Idioventricular rhythm
occurs when ventricular foci act as primary pacemakre for the heart
(20-40 bpms)
*can also have accelerated idoventricular rhythm (40-100 bpm)
sx of idioventricular rhythm
dzzy, pre-syncope, syncope
tx of idioventricular rhythm
underlying causes,
BB with CAD
atrial overdrive pacemkater
EKG finding ins idioventriculare rhythm
Rate: 20-40 or 40-100 Rhythm: Regular P wave: None P:QRS ration: None PR interval: None QRS: Wide >0.12 seconds
ventricular tachycardia
very fast ventricular rate that is dissocaited from underlying atrial rate
*no marriage of P and QRS
nonsustained VT?
Runs of three or more ventricular beats lasting <30 seconds and terminating spontaneously
Increased mortality (SCD) in patient’s with heart disease
sustained VT?
Ventricular beats lasting >30 seconds, intervention often required to terminate
High risk of reoccurrence
With LV dysfunction SCD high
monomorphic VT
The appearance of all the beats match each other in each lead (same QRS configuration)
Can deteriorate to VF
BAD NEWS
POLYMOrphic VT
Beat to beat variations is morphology
Torsades de pointes- polymorphic VT in the context of prolonged QT interval
Think ischemia
sx of VT
NST asx
palpitations, CP, SOB, presyncope, syncope, hemodymaiclly compromised
tx of vtach (if NSVT or premature beats)
BB or CCB if pt is symptomatic
tx of VTach if pt has hypotension, loss of consiousness,
synchronized cardioversion
pulseless vtach tx?
immediate defibrillation along with CPR
acute Vtach pharmacological tx
amiodarone
lidocaine
procainamide
what is brugadad syndrome?
genetic disorder that causes syncope, ventricular fibrillation and sudden death, often during sleep
torsades de pointes
Occurs with underlying prolonged QT interval:
Congenital
Drugs
Electrolyte imbalances
Can convert to a normal or ventricular rhythm
QRS morphology twist around baseline like a party streamer
Very serious: Harbinger for death, Ventricular Fibrillation
tx of torsades
Treatment: IV Magnesium, Potassium, Defibrillation
ventricular flutter
very fast vtach
- can no longer tell QRS, Twave, ST segments
- sinosoidal pattern
tx same as V tach
ventricular fibrillation
cardiac chaos
different ares of ventricles firing all at their own pace w/ no coordination or organization
what is the main cause of sudden cardiac death?
vfib
causes of v fib
myocardial infraction
hypokalemia
drug toxicity
tx of v fib
nonsynchronized defibrilattion; biphasic 120-200 J
(don’t have to synch bc there is nothing tto synch up with)
amiodarone for 24-48 hours
pulseless electrical activity
can be any rhythms at all w/o a pulse
CPR
AV blocks
Delay or interruption in the transmission of an impulse from the atria to the ventricles
Conduction blocks between sinus node and purkinje fibers
Occurs at AV node, Bundle of His and below
Key determining factor is the PR interval
first degree heart block
prolonged block in the AV node, ery impulse is conducted
what can cause a first degree heart block
meds, vagal stimulation, dz,
what will the PR interval look like?
> .20 sc
first degree sx
asx
dizzy, presyncope, syncope
tx of first degree
reverse cause, nothing, pacemaker
Mobitz I second degree
Wenckenback
Caused by a diseased AV node with a long refractory period
Progressive delay between atrial and ventricular contraction and the eventual failure of a QRS following a P wave (dropped beat)
causes of Mobitz I
Normal in individuals with high vagal tone (young, athlete)
Heart disease- RCA, inferior MI
Post mitral valve surgery
Lyme disease
Mobitz 1 sx
asx,
bradycardia
palpiations
tx of mobitz 1
unstable: atropine,pacing
stable: pacing pads in lace, revascularization, remove toxin
EGK Mobitz 1
PR interval gets larger and larger until the bieat drops
Mobtiz II
Occurs due to a diseased AV node
Block usually occurs in the Bundle of His
May lead to complete heart block
Distinguishing factor: presence of non-conducted beat without progressive lengthening of PR interval,
**pt can have bothe a I and II degree block-can be in different places
what is a third degree heart block
Complete block of the AV node
Atria and Ventricles are firing separately each to its own drum
2 pacemaker sites, atrial 60-100 bpm and ventricles 30-50 bpm, both will be regular but independent
Medical emergency, typically requires a pacemaker
