Arrythmia Flashcards
What are the
- symptoms
- ways of classifying
- 2 causes
Symptoms
- palpitation
- SOB
- dizzy, faint, syncope
Rate
-bradyarrythmia/tachyarrythmia
Location
-supraventricular/ventricular
Cause of bradycardia
- SAN slows
- SAN blocked, distal pacemakers take over
Causes of tachycardia
- Reentry
- Afterdepolarizations
ISSUES WITH IMPULSE GENERATION?CONDUCTION
What is a 3rd degree HB
- causes
- effects
- prognosis
- treatment
- ECG reading
Electrical block between A and V
Cause
- atherosclerotic CHD
- dilated cardiomyocytes => ischemic damage
- BB fibrosis
Effects
-bradycardia as latent PM takes over
Prognosis
- death if latent PM does not take over
- increased risk of asystole if more distal
Treatment
-permanent/temporary PM
ECG
-P and QRS dissociates completely
What is the mechanism behind tachyarrythmias
-reentry of trapped impulse
Impulse can only travel down conductivity system
Zone of ischemia has unidirectional conductivity, has slowed retrograde conduction
AP in this zone can only fire when tissue is not refractory
What is the mechanism behind tachyarrythmias
-triggered automaticity
What are the 2 types and what are they triggered by
Delayed afterdeloparization
- excess increased [Ca] => NaCa exchange
- increased NA/A
- Digoxin (increases vagus, decreases NaKATPase but)
Early after depolarization
- AP, Ca plateau sustained
- hypoxia
- increased NA/A
- soltalol
Can be sustained by reentry
What is ventricular tachycardia
- causes
- effects
- prognosis
- treatment
- ECG
Ectopic 120-200BPM
Cause
- reentry, ectopic from cardiac scarring
- congenital
Effects
-tachy, mono/polymorphic
Prognosis
- may compromise function => HF and death
- VF => sudden death
Treatment
- ICD
- Class !, 2, 3
- radiocatheterablation (hot/cold)
ECG
- monomorphic
- polymorphic
- P hard to see as refractory period is more frequent
What is atrial fibrillation
- cause
- risk factors
- prognosis
- treatment
- ECG
Chaotic atria, irregularly irregular ventricles
Cause
-ectopic/reentrant path in atria/pulmonary vein
Risk factors
- atrial dilation
- HF
- HTN
- hyperthyroidism, alcohol, age
Prognosis
- paroxysmal => persistent => permanent
- lack of atrial beat => stasis => thrombi in appendage => stroke
Treatment
- Class 1, 2, 3, 4 drugs
- CD
- radiocatheter ablation
- anticoagulants, LA appendage closed
ECG
- fibrillatory f waves
- no P waves, tacky QRS
What is ventricular fibrillation
- cause
- effects
- prognosis
- treatment
- ECG
Just chaos
Cause
-MI, CHD, cardiomyopathy
Effects
-poor CO
Prognosis
-leads to death
Treatment
-DF
ECG
-disorganised until heart dies
What are the 4 drug classes
I, Na block
II, B block
III, K block => Increase AP, RP
IV, Ca block
What are the 2 other drugs that can be used in arrhythmias
Adenosine
- K open, Ca block
- Increases hyperpolarisation at AVN
Digoxin
-increase vagus stimulation
What drugs control the rate
How do they do this
2, 4
Adenosine, digoxin
Decrease AVN conduction => decreased ventricular depolarization rate => increased filling time => CO increases
What drugs control the rhythm
How do they do this
1, 3
Decrease conduction OR increase the refractory period to prevent arrhythmia reentyr
What drug class does amiodarone belong to
What does it do
What is its T1/2
Why is this a problematic drug
Class 3, K blocker
Very long T1/2 => many DDI even after it has been stopped
Many severe SE
What is radio frequency catheter ablation
What kind of arrhythmias are treated with this method
Ectopic pacemaker/part of reentrant pathway destroyed w heat/cold
More commonly used with SV
Harder in VT as wall is thicker
How do implant DFs work
Where are they inserted
What are the limitations of this management method
RV, SVC
Sense, differentiate arrhythmias by rate/location => shock => cardio version
But too many => cardiac damage
How do DFs work
When would you use them
Terminate VF/VT with no CO
Cardioversion at sternum and RV apex
=> SAN reasserts sinus rhythm
+CPR + adrenaline
