arrhythmia Flashcards
What is arrhythmia?
A condition in which the heart beats with an irregular or abnormal rhythm
What is the characteristic description of Atrial Fibrillation (AF)?
Irregularly Irregular
What is the location of SA node?
Lateral aspect of SVC RA junction
What are the characteristics of SA node?
- fires off at the fastest rate, leads the normal heart rhythm
- exhibits automaticity, intrinsic pacemaker of the heart
What are the characteristics of AV node?
- slow conducting tissue, allows AV nodal delay, allows time for ventricular filling before ventricular systole
- intrinsic pacemaker of the heart but slower rate than SA node
What are the characteristics of His-Purkinje system?
- specialised rapidly conducting cardiac tissue
- allows synchronised contraction between ventricles
What controls the SA and AV nodes’ automaticity?
The brain controls SA and AV nodes via ANS through the vasomotor centre in the medulla
Bradycardia can be due to…
- Problems with Impulse Generation
Sinus Bradycardia - Interrupted conduction from atrium to ventricle
1st degree AV block:
- prolonged duration of conduction from atrium to ventricle
- asymptomatic
2nd degree AV block:
- regularly dropped AV conduction
- more P waves than QRS waves
3rd degree AV block:
- independent P waves and QRS waves
- regular PP intervals
- regular RR intervals
What are some causes of Bradycardia?
- High vagal tone
- Injury to SA node
- Drugs
- Sick sinus syndrome
- Hypothyroidism
What are some symptoms of bradycardia?
- Lethargy
- Exertional Dyspnoea
- Giddiness
- Syncope
- Asymptomatic
What is the treatment of bradycardia?
- Assess hemodynamic status
- Stop medications
- Give Atropine
- Temporary Pacing
- Permanent Pacemaker
Tachycardia can be due to…
- Physiologic
Sinus Tachycardia (exercise, stress) - Abnormal automaticity/Triggered activity
- other cardiac cells start firing spontaneously -> premature heartbeat - Re-entry
- Disorganised Activity
What are the causes of AA/TA?
- Electrolyte imbalances
- Channelopathies
- Injury to myocytes
- Anti-arrythmic drugs
AA/TA in the atrium
- Atrial ectopic
- abnormal P wave morphology - Atrial tachycardia
- abnormal P wave morphology
AA/TA in the ventricles
- Ventricle ectopic
- QRS broad and bizarre
- Ventricular depolarisation does not involve His-Purkinje system - Ventricle tachycardia
- HR > 100bpm
- QRS broad and bizarre
- Ventricular depolarisation does not involve His-Purkinje system
=> signal spreads via cell-cell and not through conduction tissue