Arrhythmias Flashcards
How can arrhythmias be divided?
Tachyarrhythmia and Bradyarrhythmia
List 4 examples of Bradyarrhythmias
- Sick sinus syndrome
- Sinus bradycardia
- Heart blocks
- BBB
What is sick sinus syndrome?
Sinus node becomes dysfunctional due to sinus node fibrosis.
Typically affects the elderly
How does sick sinus syndrome affect the rate/rhythm of the heart?
Can cause sinus bradycardia, pauses, sinus tachycardia or AF
What does this ECG of sick sinus syndrome show?
“pauses” due to sinus exit block/sinus arrest
Sick sinus syndrome causes chronotropic incompetence, what does this mean?
Inability to increase and maintain HR appropriately during exercise
Treatment of sick sinus syndrome (3)
- Conservative - asymptomatic
- Correct reversible causes
- Pacemaker for symptomatic bradycardia or sinus pauses
What is heart block?
Communication problem between he atria and ventricle
What is first degree heart block?
P-R interval elongation 0.20 seconds (5 small/1 big square) due to conduction delay at the AV node
All signals reach the ventricles
What are the 2 types of second degree heart block?
- Mobitz type 1 (Type 1) ‘Wenkebach’
- Mobitz type 2 (Type )
Compare Mobitz 1 vs 2
Excitation sometimes fails to pass through the AV node or bundle of His
Type 1: P-R interval elongation, then QRS dropped
Types 2: Constant P-R interval, then QRS dropped
What is Complete (third degree) heart block?
Atrial contractions are normal but NO electrical activity conveyed to the ventricles
Ventricles generate their own signal through ectopic pacemaker
Treatment of heart block?
- Conservative if asymptomatic and not high risk
- Correct reversible causes
- Pacemaker if symptomatic or high degree block
What is the biggest risk of complete degree heart block?
Risk of sudden death
Are pacemakers used to treat brady, tachy or both types of arrythmias?
Bradyarrhythmias
List patient groups who are high risk for asystole
- Mobitz Type 2
- Complete heart block
- Previous asystole
Treatment of Bradycardias?
- First line: Atropine 500mcg IV
- No improvement: Repeat Atropine (total of 3mg) OR Adrenaline OR Transcutaneous cardiac pacing
- Transvenous cardiac pacing
What is Atropine
List 2 s/e
antimuscarinic - inhibits the PNS
S/e: pupil dilatation, urinary retention, dry eyes and constipation
List 4 examples of Tachyarrhythmias
- AF or Atrial flutter
- SVT
- VT or VF
- Sinus tachycardia
List 4 risk factors for atrial flutter
- Obesity
- Hypertension
- Drugs (alcohol)
- Structural heart disease (valves, congenital, cardiomyopathy)
What ECG change is characteristic of Atrial fibrillation
Absent P waves
How does AF present?
- palpitations
- dyspnoea
- chest pain
- an irregularly irregular pulse
What are the two key parts of managing patients with AF
- Rate/rhythm control
- Reducing stroke risk