L6. Treatment of Cardiac Rhythm disturbances

Question 1

Define the wavelength for re-entry arrhythmia

Answer 1

Wavelength = conduction velocity * refractory period .

If wavelength is < length of tissue, excitiation can ocur

Question 2

EAD: early after depolarisation - When does it occur what arrhythmia is it related

Answer 2

• Occur in the late phase 3 period of AP
• Sympathetic stimulation could increase EAD amplitude to provoke Ventricular arrhythmia.
• Can occur in blocks of ectopic ventricular beats.

Question 3

DAD - Delayed after depolarisation: When does it occur what arrhythmia is it related

Answer 3

Occur in phase 4 period of AP,

• initiated with rapid pacing, high catecholamine levelts
• Idiopathic VT, RVOT VT