arrhythmia

Question 1

What is arrhythmia?

Answer 1

A condition in which the heart beats with an irregular or abnormal rhythm

Question 2

What is the characteristic description of Atrial Fibrillation (AF)?

Answer 2

Irregularly Irregular

Question 3

What is the location of SA node?

Answer 3

Lateral aspect of SVC RA junction

Question 4

What are the characteristics of SA node?

Answer 4

• fires off at the fastest rate, leads the normal heart rhythm
• exhibits automaticity, intrinsic pacemaker of the heart

Question 5

What are the characteristics of AV node?

Answer 5

• 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

Question 6

What are the characteristics of His-Purkinje system?

Answer 6

• specialised rapidly conducting cardiac tissue
• allows synchronised contraction between ventricles

Question 7

What controls the SA and AV nodes’ automaticity?

Answer 7

The brain controls SA and AV nodes via ANS through the vasomotor centre in the medulla

Question 8

Bradycardia can be due to…

Answer 8

1. Problems with Impulse Generation
   Sinus Bradycardia
2. 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

Question 9

What are some causes of Bradycardia?

Answer 9

1. High vagal tone
2. Injury to SA node
3. Drugs
4. Sick sinus syndrome
5. Hypothyroidism

Question 10

What are some symptoms of bradycardia?

Answer 10

1. Lethargy
2. Exertional Dyspnoea
3. Giddiness
4. Syncope
5. Asymptomatic

Question 11

What is the treatment of bradycardia?

Answer 11

1. Assess hemodynamic status
2. Stop medications
3. Give Atropine
4. Temporary Pacing
5. Permanent Pacemaker

Question 12

Tachycardia can be due to…

Answer 12

1. Physiologic
   Sinus Tachycardia (exercise, stress)
2. Abnormal automaticity/Triggered activity
   - other cardiac cells start firing spontaneously -> premature heartbeat
3. Re-entry
4. Disorganised Activity

Question 13

What are the causes of AA/TA?

Answer 13

1. Electrolyte imbalances
2. Channelopathies
3. Injury to myocytes
4. Anti-arrythmic drugs

Question 14

AA/TA in the atrium

Answer 14

1. Atrial ectopic
   - abnormal P wave morphology
2. Atrial tachycardia
   - abnormal P wave morphology

Question 15

AA/TA in the ventricles

Answer 15

1. Ventricle ectopic
   - QRS broad and bizarre
   - Ventricular depolarisation does not involve His-Purkinje system
2. 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

Question 16

Re-entry in atrium

Answer 16

Atrial flutter

• no P waves
• sawtooth baseline

Question 17

Re-entry in ventricles

Answer 17

Supraventricular tachycardia

• QRS broad and bizarre
• Ventricular depolarisation does not involve His-Purkinje system
  => signal spreads via cell-cell and not through conduction tissue

Question 18

Disorganised activity in atrium

Answer 18

Atrial Fibrillation

• no P waves
• sawtooth baseline
• irregular RR intervals

Question 19

Disorganised activity in ventricle

Answer 19

Ventricular Fibrillation

Question 20

What are some symptoms of tachycardia?

Answer 20

1. Palpitations
2. Cardiac arrest
3. Giddiness
4. Syncope
5. Asymptomatic

Question 21

What is the treatment for tachycardia?

Answer 21

1. Assess hemodynamics status
2. Implantable cardiac defibrillators
3. Medications
4. Electrophysiology study and ablation