Broad Complex Tachycardia

Question 1

Indications for CRT

Answer 1

EF <35%
Sinus rhythm
LBBB, QRS>150m/s
Optimised medical therapy
Survival > 1 year

Question 2

Capture beat

Answer 2

Sinus node w/ appropriate AV conduction - resulting in normal QRS duration

Question 3

Fusion beat

Answer 3

Sinus and ventricular beat merge to form a hybrid waveform

Question 4

What features on ECG favours VT over aberrancy?

Answer 4

Extreme axis deviation
Absence of RBBB/LBBB morphology
AV disassociation
Capture and fusion beats
Positive or negative concordance throughout chest leads
Josephson’s sign: Notching at nadir of S wave
Brugada sign: distance from onset of QRS to S wave >100ms
RSR complex w/ taller LEFT rabbit ear

Question 5

Mechanism of VT

Answer 5

(Most commonly re-entry)
Two separate conduction pathways
One pathway blocked due to myocardial scarring (due to ischaemia/infection)
Ventricular impulse re-enters via blocked pathway –> creating re-entry circuit

Question 6

Differentials for VT

Answer 6

SVT with aberrancy (due to BBB or accessory pathway)
Pacemaker mediated tachycardia
Metabolic derangements
Poisioning w/ sodium channel blockers (TCA)

Question 7

Torsades de Pointes criteria

Answer 7

Polymorphic VT + QT Prolongation

Question 8

What is ‘R on T’ phenomenon? And what does it indicate?

Answer 8

PVC occurs during preceding T wave
Initiation of PVT

Question 9

Indications for ICD (Primary Prevention)

Answer 9

For patients on guideline-directed medical therapy at risk of SCD

• Patient with prior MI (40 days prior) + LVEF <30%
• Cardiomyopathy + LVEF <35
  >CM, persistent LVEF <35% after 3 months of optimal medical therapy or revasicularisation- DANISH trial reports it does not significantly reduce mortality in non-ischaemic CM
  >If broad QRS, would be suitable for combined ICD and biventricular pacing (CRT-D)
• Patients with prior MI, LVEF < 40%, VF or sustained VT induced on EP studies
• Underlying disorders w/ high risk of SCD
  > Congenital long QT syndrome w/ recurrent symptoms and/or tDP on optimised medical therapy
  > High-risk HOCM, arrhythmogenic RV cardiomyopathy, cardiac sarcoidosis
  > High-risk arrhythmia - Brugada’s syndrome, catecholaminergic polymorphic VT, channelopathies
• Pts with some muscular dystrophies with cardiac involvement

Question 10

Indications for ICD (Secondary Prevention)

Answer 10

• Patients with a prior episode of resuscitated VT/VF or sustained HD unstable VT - reversible cause not identified
  > Underlying heart disease
  > Idiopathic VT/VF
  > Congenital QT syndrome
  Not patients with VT/VF within first 48h of AMI
• Patients with sustained VT in the setting of heart disease (valvular, ischaemic, hypertrophic, dilated, or infiltrative) or channelopathies
• Unexplained syncope w/ high suspicion of VT/VF

Question 11

Which beta-blockers have evidence in reducing risk of syncope and sudden cardiac death in congenital long QT syndrome?

Answer 11

1) Propanolol
2) Nadolol

Question 12

Most common cause of VF arrest

Answer 12

IHD

Question 13

Stable angina + maximised medical therapy + positive stress test. Next step?

Answer 13

Invasive angiogram