Cardiology 11 - Arrhythmias

Question 1

give the 2 shockable rhythms

Answer 1

VT ventricular tachycardia

VF ventricular fibrillation

Question 2

give the 2 non shockable rhythms

Answer 2

asytole - none seen

PEA - pulseless electrical activity (all activity outside VT/VF including sinus rhythm with no central pulse)

Question 3

summarise + categorise the treatment of tachycardia

unstable x2 treatment
narrow complex 3 types + treatment
broad complex 3 types + treatment

Answer 3

unstable

• up to 3 synchronised shocks
• consider amiodarone infusion

NARROW
AF - beta blocker or diltiazem
AFlutter - beta blocker
SVT - vagal man + adenosine

BROAD
VT/unclear - amiodarone infusion
SVT + BBB - treat as SVT
Irregular - seek advice

Question 4

key aspects of atrial flutter

Answer 4

re-entrant rhythm
300bpm atrial
150bpm ventricular
saw-toothed baseline

Question 5

4 assoc conditions with atrial flutter

Answer 5

hypertension
ischaemic heart disease
cardiomyopathy
thyrotoxicosis

Question 6

3 aspects of atrial flutter treatment

Answer 6

rate/rhythm control (beta block or cardiovert)
radiofrequency ablation
anticoagulation

Question 7

define supraventricular tachycardia

Answer 7

<0.12 seconds narrow complex QRS with immediate T wave seen

caused by electrical signal from ventricles re-entering

Question 8

3 main types of SVT

Answer 8

AVNRT - re-entry via AV node
WPW - accessory pathway
atrial tachycardia - ectopic electrical trigger other than sino-atrial node

Question 9

6 steps in managing SVT

Answer 9

1. place on continuous ECG monitoring
2. valsalva manoeuvre (blow hard against resistance)
3. carotid sinus massage (one side gently)
4. adenosine 6mg, 12, 12
5. verapamil
6. DC cardioversion

Question 10

give info on adenosine

Answer 10

slows AV node conduction 
must give as rapid bolus 
causes brief asystole/brady
scary/ doomed feeling 
fast IV bolus in grey proximal cannula

Question 11

5 conditions to avoid with adenosine

Answer 11

asthma
COPD
heart failure
heart block 
severe hypotension

Question 12

long-term management of patients with paroxysmal SVT

Answer 12

medication (beta block, calcium channel block, amiodarone)

radiofrequency ablation

Question 13

info on Wolff Parkinson White

Answer 13

also known as atrioventricular re-entrant tachycardia

Bundle of Kent accessory

definitive treatment is radiofrequency ablation

Question 14

ECG changes in WPW

Answer 14

short PR interval 
narrow QRS complex (but can be wide!)
delta wave (slurred QRS upstroke)

Question 15

which medications are contraindicated in WPW patients that also have AF/flut

Answer 15

anti-arrhythmics e.g. beta blocker, cal blocker, adenosine

as can lead to polymorphic wide complex tachycardia by increasing transfer through accessory pathway (as less can get through AVN)

Question 16

4 indications for radiofrequency ablation

Answer 16

atrial fib
atrial flut
SVTs
WPW syndrome

Question 17

causes of prolonged QT interval
1 inherited
6 medications
3 electrolyte

Answer 17

long QT syndrome
antipsychotics, citalopram, flecanide, sotalol, amiodarone, macrolides
low potassium, low magnesium, low calcium

Question 18

acute management of torsades de pointes (will be very temporary, either reverts to normal or VT)

Answer 18

correct the cause
magnesium infusion
defib if VT

Question 19

4 steps in long term management of long QT syndrome

Answer 19

avoid prolonging meds
correct ion deviations 
beta blockers (not sotalol)
pacemaker or defib implant

Question 20

define ventricular ectoopic

Answer 20

individual random abnormal broad QRS complexes on background of normal ECG

bigeminy is when they appear after every sinus beat

Question 21

management of ventricular ectopics x3

Answer 21

check for anaemia, ion disturbance, thyroid
reassure if healthy
seek advice if concerning findings or background heart conditions

Question 22

define the heart blocks

Answer 22

first degree - long PR interval only >0.20s

second degree - some atrial impulses not transmitted
Mobitz 1 - PR lengthens then dropped beat
Mobitz 2 - normal PR with random dropped beats in some ratio
2:1 block - 2 Ps for each QRS

third degree - complete, no observable relationship between P and QRS waves

Question 23

define the treatment pathway for bradycardias

Answer 23

stable - observe

unstable or risk of asytole:

1. atropine 500mcg IV
2. repeat up to total dose of 3mg
3. inotropes e.g. norad
4. transcutaneous pacing

Question 24

which heart blocks have a high risk of asystole

Answer 24

Mobitz 2, complete, previous asystole

must have temporary transvenous pacing and then permanent pacemaker

Question 25

antimuscarinic side effects

Answer 25

inhibit parasympathetic system

pupil dilation
urinary retention
dry eyes
slow bowels