CWEI dysrhythmias Flashcards
list 7 primary causes of dysrhythmias
structural heart disease
metabolic disease
electrolyte disorder
trauma
drugs/ toxins
sepsis
neoplasia
define dysrhythmia
an abnormal heart rhythm caused by a disturbance in the hearts electrical conduction system
why do we need to be careful with antidysrhythmic medication
it can be proarrhythmic and cause worsening of the problems
List 4 treatment options for dysrhythmias - which are most common
Most common:
Anti-dysrhythmic drugs
Pacemaker
ablation with catheters
implantable cardiovertors
when should we consider treating dysrhythmias with antidysrhythmia medication
if the heart rate or frequency are high enough to cause a drop in CO or if there are life threatening rhythms
Describe how to interpret the ECG
what is the heart rate
is the rhythm regular or irregular
do the ECG waves appear normal
Is each P wave followed by a QRS?
Is there a P wave before each QRS?
ECG measurements
why are supraventricular rhythms often seen in structural heart disease
the atria stretches and causes the cardiomyocytes to become unstable
why are ventricular rhythms often seen in systemically sick patients
cytokines damage cardiomyocytes and generate rhythm abnormalities
List the different types of dysrhythmias
Bradyarrhythmia
Tachyarrhythmia- supraventricular and ventricular
define bradydysrhythmias
abnormally slow rhythms
What is Supraventricular tachycardia
high rate arising in or above the AVN - narrow and upright complexes
what is ventricular tachycardia
high rate arising from the ventricles - usually wide and bizarre complexes
what happens in sinus arrest
is a bradyarrhythmia
SAN stops firing
pause noted on ECG with no P-QRS-T complex
define sick sinus syndrome
arrhythmia in which bradycardia alternates with tachycardia
what is atrial standstill
Atrial depolarization does not occur when SA node discharges
complete absence of p-waves
list the clinical signs of bradydysrhythmias
weakness
lethargy
syncope
sudden death
describe atrioventricular block type 2
occasional block; p-wave not conducted- can happen in high vagal tone, is common under GA - rarely causes clinical issue
how can we test if a bradycardia is vagally mediated
run them around and see if the heart rate increases or give them atropine and monitor - both should get rid of the bradycardia if it is vagally mediated
Describe sinus arrythmia
is a normal sign in a dog
when heart rate speeds up on inspiration and slows down on expiration
occurs when parasympathetic is in control
describe how we can treat bradydysrhythmias
treat the primary cause
pacemaker implantation
parasympathetic drugs
List the 2 main types of tachyarrythmias
Supraventricular Tachycardia (SVT)
Ventricular Tachycardia (VT)
describe Supraventricular Tachycardia (SVT)
ventricular impulse conduction normal and QRS normal in appearance – tall and narrow
Problem with atria AV node
describe Ventricular Tachycardia
All rhythm disturbances originating from within the ventricles
Ventricular conduction abnormal leading to wide and bizarre QRS complexes
when do we treat supraventrciular tachycardias
if the output is poor and clinical signs are seen
describe premature beats
any beat that occurs before it is expected- can be supraventricular or ventricular
what drug do we give if ventricular dysrhythmia is critical
IV lidocaine
what drug do we give if the ventricular dysrhythmia has stable/ episodic sign
solatol
describe what you see second degree AV block on ECG
P wave occasionally not conducted throguh the AV node
describe what you see with third degree AV block on ECG
persistent failure of conduction through the AV node
what is atrial fibrilation
rapid random ineffective contractions of the atrium
type of supraventricular tachycardia
desribe how you treat atrial fibrilation
Diltiazem and digoxin often effective
describe ventricular tachycardia
sequence of or >4 ventricular beats with a rate > 160bpm – often a fast and unstable rhythm
describe ventricular flutter
a very rapid VTAC in which T waves and QRS are no longer distinguishable; DANGER – often precedes death- can see under GA, animal about to crash
which Antiarrhythmic drugs act by altering ion flow
class 1, 3 and 4
which Antiarrhythmic drugs act by impavting the sympathetic innervation to the SA and AV nodes
class 2 drugs
+ sotalol
slows the heart rate
