Clincial Treatment of Arrhythmia Flashcards
The last portion of the PR interval is represented by conduction time through ____
bundle branches and Purkinje
Two types of arrhythmias
- too slow called?
- too fast called?
too slow = bradyarrhythmia
too fast = tachyarrhythmia
Types of SA node bradyarrhythmia (4)
1) sinus bradycardia
2) sinus arrest/pause
3) tachy-brady syndrome
4) chronotropic incompetence (can’t make appropriate HR with exercise)
Define Sinus bradycarida
SA node <60 bpm
Define sinus arrest
pause in rate of SA node firing
failure of sinus node discharge –> absence of atrial depol and ventricular asystole
with sinus arrest, there is ____ betwen pause and cycle length
NO RELATIONSHIP BETWEEN PAUSE AND CYCLE LENGTH
brady-tachy syndrome
intermittent episode of slow and fast rates from SA node or atria
how does brady-tachy manifest
atrial tachycarida, flutter, fibrillation
what occurs after stopping tachycardia?
long pauses from SA node
define chronotropic incompetence
cannot incr heart rate with exercise
oscillation of HR with activity
Types of AV node bradyarrhythmia
1st degree AV block
Mobitz 1 2nd degree AV block (Wenkebach)
Define 1st degree AV block
AV conduction delayed
prolonged PR interval (>200 ms)
Define 2nd degree AV block
atrial depol sometimes don’t reach ventricle
Define 2nd degree AV block - Mobitz 1 (Wenckebach)
progressive prolonging of PR interval until ventricular beat dropped (no QRS)
QRS usually normal
Types of conduction problems below AV node (infranodal= His PUrkinje)
Mobitz II 2nd degree AV block
Complete heart block
Define Mobitz II 2nd degree AV block
intermittent dropped ventricular beats preceded by constant PR interval
how to separate Mobitz 1 vs. 2
Mobitz 1 = difference btwn PR interval > 0.02 sec
Mobitz 2 = difference between PR interval < 0.02 sec
Define 3rd degree block = complete heart block
no conduction from atria to ventricles
no relationship btwn P and QRS waves (variable PR interval)
initiate new QRS below AV node
40-60 = His bundle initiate
<40 = Purkinje fiber initiate
when should you be concerned about bradyarrhythmia
1) when patient symptomatic
2) when rhythm is infranodal (below AV node) –> can become 3rd degree block
Steps of treating brayarrhythmia chronic
1) find and treat reversible causes - ischemia/infarct/hypothyroidism/neuro/Lyme
2) stop offending meds (antiarryhtmic, clondiine, lithium..)
Steps of treating bradyarrhythmia
acute treatment for unstable
beta agonist (dopamine/isoproteronol)
transcutaneous pacing (esp if infranodal)
temporary transvenous pacing
Steps of treating bradyarrhythmia
long term
pacemaker
Two types of tachyarrhythmia
above ventricle = supraventricular tachycardia
at ventricle = v-tach, v-fib
Types of irregular SVT
1) atrial fibrillation = no discrete P
2) multifocal atrial tachycardia = 3+ P
3) atrial flutter = variable conduction + flutter waves
what is a regular SVT?
1:1 P:QRS
How to treat SVT
1) if unstable (hypotension/HF) = shock/cardiovert
2) if stable and irregular SVT, rate control, antiarrhythmic, or cardiovert
3) if stable and regular SVT, ADENOSINE (block AV node transiently to see P waves) to diagnose
5 C’s of Afib
1) cause: Reverse
2) control rate
3) antiCoagulation
4) control rhythm
5) cure: ablation
Causes of Afib
1) HTN
2) Ischemic heart disease
3) mitral valve disease
4) alcohol
5) cardiomyopathies
6) hyperthyroidism
7) lone AF = 14%
Immediate treatment options for AFib
1) cardiovert = for unstable patients
2) control rates
How to control rhythm in AFib via cardioversion
1) Electrical = DC shock 70-90% day procedure with sedation
2) pharm = less successful, no sedation
Class 3
Class 1C
Maitenance of rhythm control in Afib
Class 1C (contraindicated in CAD and structural heart disease)
Class 3
ALWAYS Anticoagulation due to thromboembolism risk
Rate control in AFib
1) beta blocker (good with exercise)
2) digoxin (not good with exercise)
3) verapamil
4) diltiazem
5) amiodarone (esp with decomp heart failure)
side effect of rate control meds
heart block
rhythm control via cardiac ablation
target triggers = mainly left atrium
atrial flutter treatment
similar to Afib
catheter ablation better than meds; can be curative
which has lower risk of ablation, atrial flutter or afib
atrial flutter
how to perform atrial flutter ablation
target isthmus in right atrium btwn tricuspid valve and IVC
to block circuit causing atrial flutter
Other SVT
1) AV node reentry tachycardia
(circuit in AV node)
2) accessory pathway mediated tachy
3) focal atrial tachycardia
define accessory pathway mediated tachcyardia
abnormal connection btwn atrium and ventricle
define focal atrial tachycardia
abnromal focus of atrial tissue with incr automaticity “hotspot”
how to treat “other SVT’s”
1) nonpharm = vagal
2) meds only for symptoms
- beta blocker, Ca2+ ch blocker for AV node
- class 1 to decr ectopic foci
3) cardiac ablation
define: ventricular tachyarrhythmia
wide complex tachy
if patient has coronary artery disease, 90% of the time the wide complex tachycardia is ____
ventricular tachycardia
acute treatment for stable v-tach
meds = amiodarone, lidocaine, procainamide
treat underlying cause
acute treatment for UNSTABLE v-tach
SHOCK!!!!!!
treat underlying cause
meds
long term treatment for v-tach WITH NO STRUCTURAL HEART DISEASE
1) usu idiopathic = focal benign trigger
2) use meds/ablation
RARELY DEFIBRILLATOR USED
long term treatment for v-tach WITH STRUCTURAL HEART DISEASE
1) treat underlying cause
2) USE DEFIBRILLATOR because sudden death
where do v-tachyarrhythmias arise?
outflow tracts of RV or LV
what meds to use for v-tachyarrhythmias?
1) beta blocker
2) ca2+ channel blocker
3) class 1C
4) class 3
when is defibrillator needed for v-tachycarrhythmias?
1) if pt has sudden cardiac arrest due to VT or VF w/o reversible cause
2) risk of MI
- ischemic heart disease, EF<35%
ischemic disease, EF 35-40% + inducible VT
HCM, cardiac sarcoid, congenital heart disease, ARVC
Difference betwn defibrillator implant and pacemaker
leads of defib = coils
Sudden Cardiac Death cause
due to ventricular fibrillation
treatment for sudden cardiac death
bystander basic life support
early defib with an external defibrillator
if greater than 2 risk factors then blood thinner for afib is ____
warfarin
