Ventricular Arrhythmias

Question 1

what causes ventricular arrhythmias?

Answer 1

SA and AV nodes fail to pace the heart leading to no atrial activity

Question 2

examples of ventricular arrhythmias

Answer 2

premature ventricular contractions (PVC)
idioventricular arrhythmias (ventricular escape rhythm)
agonal rhythm
VT
VF
torsades de pointes
asystole
PEA

Question 3

what are premature ventricular contractions (PVCs)?

Answer 3

ectopic beats that arise from irritable sites in the ventricles

Question 4

causes of premature ventricular contractions?

Answer 4

exercise
stress
caffeine
heart disease
electrolyte imbalances
hypoxia
tricyclic antidepressants
digoxin toxicity

Question 5

management of premature ventricular contractions

Answer 5

reduced CO can lead to HF, VT, VF
oxygen
lidocaine
procainamide

Question 6

what is a ventricular escape rhythm (idioventricular arrhythmia)?

Answer 6

last ditch effort by the ventricles with a rate of 20-40bpm

Question 7

causes of ventricular escape rhythm

Answer 7

digoxin
MI
metabolic/ hyperkalaemia
cardiomyopathy

Question 8

management of ventricular escape rhythm

Answer 8

usually leads to cardiac arrest so atropine, pacing
dopamine if hypotension
CPR

Question 9

define agonal rhythm

Answer 9

<20bpm

frequently seen in unsuccessful resuscitation efforts

Question 10

causes of agonal rhythm

Answer 10

trauma
acute MI
natural progression to death

Question 11

management of agonal rhythm

Answer 11

CPR

Question 12

when is VT seen?

Answer 12

almost always occurs in diseased hearts

Question 13

what is ventricular tachycardia?

Answer 13

rhythm where 3 or more PVCs arise in sequence at a rate of greater than 100bpm

Question 14

causes of VT

Answer 14

heart disease
myocardial ischaemia
prolonged QT
electrolyte imbalance
digoxin toxicity
CHF

Question 15

management of VT

Answer 15

CPR
amiodarone
lidocaine
cardiovert
chronic= ICD or ablation if re-entry

Question 16

what is VF?

Answer 16

multiple weak ectopic foci in the ventricles

no coordinated contraction as impulses not through normal conduction pathway

Question 17

causes of VF

Answer 17

AMI
untreated VT
electrolytes
hypothermia
drug toxicity/ overdose
trauma

Question 18

management fo VF

Answer 18

CPR
cardiovert

mimicked by electric razor or shivering

Question 19

what is torsades de pointes?

Answer 19

VT associated with prolonged QT interval

Question 20

causes of torsades de pointes

Answer 20

prolonged QT
VT drugs
phenothiazine or tricyclics
overdose
electrolytes (hypokalaemia and hypomagnesaemia)

Question 21

what drugs cause prolonged QT

Answer 21

metformin
erythromycin
ramipril

Question 22

management of torsades de pointes

Answer 22

CPR
eliminate predisposing factors
magnesium sulphate bolus
cardioversion or defib if unstable

Question 23

what is asystole?

Answer 23

ventricular standstill

Question 24

causes of asystole

Answer 24

myocardial damage
secondary to AMI
failure of pacemaker
tamponade
prolonged VF
PE

Question 25

what is PEA?

Answer 25

absence of pulse and myocardial activity but electrical activity is still present

Question 26

causes of PEA

Answer 26

hypovolaemia (MOST COMMON)
hypoxia
acidosis
hypo/hyperkalaemia
hypothermia
toxins
tamponade
tension pneumothorax
thrombosis
trauma
massive MI
overdose on tricyclics