Lecture 8 - Arrhythmias

Question 1

causes of arrhythmias

Answer 1

AMI, heart failure, hyperthyroidism, hypokalemia, autonomic dysfunction, therapeutic/abuse drugs, inherited mutations, fever

Question 2

types of ventricular arrhythmia

Answer 2

1. VPB (ventricular premature beat) - mildest type, not normally treated
2. VF (ventricular fibrillation) - most severe, rapidly lethal

Question 3

initiation of arrhythmias

Answer 3

normal heart beat starts in SA node (pacemaker cells)
if heart beat originates somewhere else, due to abnormal pacemaking (automaticity) or failure of conduction to stop at the end of the heart beat (re-entry)

Question 4

mechanisms of re-entry

Answer 4

caused by localised slow conduction due to depolarisation
makes the wave-front meander and become ragged
wave-front may split into 2 and re-enter its original pathway