Test 2: 28 ekg Flashcards
how to get HR on 25 mm paper
(count RR interval over 30 boxes) x 10
what is HR- 25 mm/sec paper
30 boxes= 6 sec
17 QRS x 10= 170 bpm
anticholinergics will do what to HR
increase
used to treat hypotension
how to manage arrhythmia under anesthesia
identify
determine significance- impact on CO and potential for progression
continue to monitor or treat is needed- correct underlying cause if possible, administer anti-arrhythmics if needed
sinus arrhythmia
- Normal variation of sinus rhythm → Related to changes in vagal tone associated with respiration
- Common in dogs
- Regularly irregular- varying R-R interval
- No need to treat unless significant bradycardia
wandering pacemaker
- Rate: low-normal
- P for every QRS, QRS for every P
- P wave morphology changes → Origin of sinus focus changes
- Typically due to increased vagal ton
- no need to treat unless significant
bradycardia
what can cause sinus bradycardia
hypothermia
Drugs (opioids, alpha-2 agonists, deep inhalant anesthesia)
increased vagal tone
* Manipulation of eye (oculcardiac reflex), larynx/trachea, abdominal viscera
treat sinus brady?
Treat if hypotensive or excessively low impacting CO
- Address underlying cause
- Reverse alpha-2 agonist if hypertensive phase
- Administer anti-cholinergic (atropine or glycopyrrolate)
how do anticholinergics work
Competitively antagonize the effects (parasympatholytic) of Ach at cholinergic postganglionic sites (muscarinic receptors)
work on cardiac M2 receptors to increase HR and increase BP
atropine, glycopyyrolate
what are two anticholinergics used during anesthesia
Atropine: faster onset, shorter acting- 1st choice for emergencies
Glycopyrrolate: slower onset, longer acting, doesn’t cross BBB or placenta
used to treat hypotension and slow HR
sinus arrest
- Low heart rate,Irregular rhythm
- Origin: Sinus node fails to depolarize→ pause
- Prolonged sinus node arrest→ escape beat
- atrial, AV junction or ventricular
- Due to increased vagal tone
- If prolonged or recurrent→↓CO,
- treat: atropine, glycopyrrolate
how to treat
sinus arrest
- If prolonged or recurrent→↓CO,
- treat: atropine, glycopyrrolate
what are some causes of sinus tach
increased sympathetic tone
Causes:
* Pain
* Stress
* Hypovolemia
* Hyperthermia
* drugs (anticholinergics, beta-agonists)
APC
- Normal heart rate (species/breed/age), Irregular Rhythm
- APC(arrow)arrives early
- Origin: ectopic atrial site
- P wave different configuration but normal QRS configuration
- normal P waves and QRS complexes are related
- Common in anesthetized horses
- No treatment required typically
treat?
APC
no treatment required typically
common in anesthetized horses
what?
supraventricular tachycardia
causes
Supraventricular Tachycardia
* High heart rate, regular rhythm, P may be lost in T wave
* Tachyarrhythmia that arises from atrial or atrioventricular (AV) nodal or
junctional tissue
* Potential Causes: primary cardiac disease, severe systemic disease, anesthetic drugs
* Treat underlying cause, beta- blockers, diltiazem, can try vagal maneuver
how to treat
supraventricular tachycardia
Treat underlying cause, beta- blockers, diltiazem, can try vagal maneuver
what
Afib
- Heart rate normal to high, Irregularly irregular rhythm with varying R – R intervals
- Random, disorganized depolarization of atria with no coordinated atrial contraction
- No normal P waves,“f”(fibrillation) waves, QRS morphology is normal
- Ventricular rate will be normal to increased
causes
Afib
- Can be pre-existing or develop during anesthesia
- Due to large atria +/- changes in vagal tone
- Horses can be isolated
- Cows can be related to GI disease
- Canine typically due to heart disease → atrial dilation
how to treat Afib
If pre-existing treat prior to anesthesia when possible
If develops during anesthesia treatment depends on hemodynamic consequences
- Treat underlying cause when applicable
- Can try lidocaine
- Electrocardioversion
- Rate control
1st degree AV block
PR interval longer due to conduction delay through AV node
treat 1st degree AV block?
prolonged PR intervals from conduction delay through AV node
May be due to ↑vagal tone or anesthetic drugs
- No adverse hemodynamic effects, no treatment required
2nd degree AV block- Mobitz 1
dropped beat- P wave not followed by QRS
P-R interval becomes progressively prolonged
normal in athletic horses with high vagal tone
common after use of ⍺2 agonist in the horse or dog
what does 2nd degree AV block Mobitz 1 look like
- P-R interval becomes progressively prolonged
- Eventually results in complete block and a lack of QRS complex (“dropped beat”)
what does 2nd degree AV block, mobitz type II look like
Consistent P-R interval with occasional complete conduction block (dropped beat)
treat 2nd degree AV block?
- Only required if causing↓ BP/MAP or CO
- Reduce inhalants / anesthetic drugs
- Anticholinergics
- Reversal agents (caused by ⍺2 agonist)
- Chronotropic agents
what
3rd degree AV block- atria and ventricles are contracting independent of each other
Complete failure of conduction between atria and ventricles
* normal P waves
* Ventricular escape rhythm is slow and regular, QRS configuration
depends upon location of ectopic pacemaker
* P waves and QRS complexes are dissociated
Slow ventricular rate causes marked reduction in cardiac output
how to treat
3rd degree AV block: atria and ventricles contracting at different rates
Treatment:
* pacemaker is the definitive treatment
* Dobutamine (β agonist), Isoproteronol can be attempted → try to increase ventricle contraction
what
VPC
wide and bizzare QRS
early beat with no P wave
causes
VPC
Potential Causes: Myocarditis, hypoxemia, electrolyte and acid-base
abnormalities, disease states (GDV, equine colic), and some drugs
(barbiturates)
* Can be catecholamine induced
* May have pulse deficits
treat?
VPC- wide and bizzare
May have pulse deficits
* Treat with lidocaine if progressive or multiform
what
AV dissociation
often called accelerated idioventricular rhythm (AIVR)
Atria and ventricles depolarize independently
* P waves and QRS complexes are not
associated
* Regular rhythm; atrial rate is normal/slow; ventricular increased compared to the normal ventricular escape rate
causes
AV dissociation- P and QRS independent of eachother but ventricular pace is faster then 3rd degree AV block
often called accelerated idioventricular
rhythm (AIVR)
Associated with GI disease (dog, horse), anesthesia (cats)
how to treat
Associated with GI disease (dog, horse), anesthesia (cats)
* Treat underlying disease
* Increase sinus rate if slow and causing hemodynamic effects (cats usually)
AV dissociation- P and QRS independent of eachother but ventricular pace is faster then 3rd degree AV block
often called accelerated idioventricular
rhythm (AIVR)
slower then Vtach
what
V tach
> 4 VPCs in a row, fast rate, no p-waves, wide QRS
Can progress to ventricular fibrillation
how to treat
Vtach
Can progress to ventricular fibrillation
Treat with lidocaine or amiodarone
May require electrical conversion if pulseless
what
V fib
No discernable complexes, random depolarization of ventricle with no contractions
treat?
V fib
Defibrillation is treatment of
choice
* Amiodarone +/- Mg (torsades) can be
attempted in addition if not responsive to defibrillation
* Can try precordial thump if no defibrillator available
what happens with pulseless electrical activity
EKG looks weird normal
no pulseox
CO2 drops on capnograph
no pulse on doppler or A line or by palpation
Need CPR
* start compressions and ventilation
* Administer Epinephrine
* Treat underlying cause of arrest
how to treat
asystole
CPR
* Chest compressions & ventilation
* Epinephrine
* Correct underlying cause if possible
what can happen to EKG with hyperkalemia
- tall T wave
- Shortened QT interval
- Prolonged PR interval & Widened QRS
- Decreased amplitude & Widened P wave
- Absence of P waves & Bradycardia with sinoventricular rhythm
- Sine Wave, Ventricular Fibrillation, Ventricular Asystole
how to treat hyperkalemia
Direct antagonism of the membrane actions
* Administration of calcium
Increased K entry into cells
* Glucose and insulin
* Sodium bicarbonate
* Beta-2 Agonists
Promote excretion or removal of potassium
* Diuresis, diuretics
* Dialysis
