Broad complex tachycardias: ventricular ectopics, ventricular tachycardia, prolonged QT syndrome,

Question 1

What are ventricular ectopics?

Answer 1

Ventricular ectopics are premature ventricular contractions, they can manifest as extra beats, missed beats or heavy beats

Question 2

Causes of ventricular ectopics + risk of ventricular ectopics

Answer 2

Most common post-MI arrhythmia

Happens because of development of new site of depolarization in non-nodular ventricular tissue, development of a re-entry circuit (slow-conducting tissues after MI)

Ventricular ectopics are risky because they can provoke VFib

Question 3

Signs and Sx of ventricular ectopics

Answer 3

Sx:
- palpitations
- lightheadedness
- syncope
- atypical chest pain

Signs
- variable/decreased intensity of heart sounds
- variable pulse rhythm
- visible jugular pulse

Question 4

Ix for ventricular ectopics

Answer 4

ECG: wide QRS (>0.12s)

Question 5

Tx for ventricular ectopics

Answer 5

reduce coffee intake

BBlockers, CCB, amiodarone

Radiofrequency catheter ablation, cardiac defibrillators

Question 6

What is a ventricular tachycardia?

Answer 6

Pulse rate of >120bpm with 3 or more ventricular extrasystoles (irregular beats) in a row

Question 7

How does ventricular tachycardia cause reduced cardiac output

Answer 7

Rapid ventricular beating –> inadequate filling of ventricles due to rapid HR and lack of coordinated atrial contraction –> reduced CO

Question 8

Causes of ventricular tachycardia

Answer 8

1. Coronary or structural heart disease (Fallot’s tetralogy)
2. e- deficiency
3. caffeine
4. MI

Question 9

Signs and Sx of ventricular tachycardia

Answer 9

Sx
- breathlessness (due to decreased lung perfusion)
- chest pain (decreased heart perfusion)
- palpitations
- light headedness (decresed brain perfusion)

Signs:
- hypotension
- raised JVP
- tachypnoea
- tachycardia

Question 10

What can Vtachy deteriorate to?

Answer 10

Vfib: re-entrant patterns that cause chaotic depolarizations without mechanical effects = no CO = no cardiac arrest

Question 11

Ix for Vtachy

Answer 11

• HR 180-200bpm
• regular
• wide complex (>0.12s)

Question 12

Tx for Vtachy

Answer 12

Oxygen
DC cardioversion

Unstable VT: amiodarone, replenish Mg2+ or other e-

Question 13

What is prolonged QT syndrome? What are the 3 types?

Answer 13

Long QT interval = ventricular repolarisation is greatly prolonged

LQTS1: arrhythmia provoked by exercise
LQTS2: provocation associated with emotion and acoustic stimuli
LQTS3: can occur during sleep/rest

Question 14

What’s a complication of LQTS?

Answer 14

Torsade de pointes: QRS complex appeas to twist around the baseline –> could lead to VF and sudden cardiac death

Question 15

Ix for LQTS

Answer 15

Prolonged QT interval
male: >0.44s
Female: >0.46s

Question 16

Tx for QTS?

Answer 16

Treat underlying cause, bblockers, avoid competitive sports that could trigger LQTS