Arrhythmias

Question 1

What are some possible symptoms of arrhythmias?

Answer 1

Palpitations
SOB
Dizziness (presyncope)
LOC (syncope)
Sudden cardiac death
Angina
Heart failure

Question 2

Which investigations should be done for a suspected arrhythmia?

Answer 2

12 lead ECG
Exercise ECG (for ischaemia, exercise induced arrhythmia)
24 hour Holter ECG
Echocardiogram
Electrophysiological study

Question 3

What is the purpose of an electrophysiological study?

Answer 3

Trigger the arrhythmia and study its mechanism/pathway

Opportunity to treat the arrhythmia by delivering radio frequency ablation to extra pathway

Question 4

What is pre-excitation a sign of and what does it look like on an ECG?

Answer 4

Wolf-Parkinson-White (pre-excitation of the ventricles)

• slurred upstroke of QRS = delta wave
• wide QRS

Question 5

What is normal sinus arrhythmia?

Answer 5

Variation in HR during respiratory cycle due to reflex changes in vagal tone
–> inspiration decreases vagal tone –> increases HR

Question 6

What are some causes of sinus bradycardia?

Answer 6

• physiological e.g. athlete
• drugs e.g. beta-blockers
• ischaemia - common after inferior STEMI

Question 7

What are the treatment options for sinus bradycardia?

Answer 7

• atropine if acute

- pacing if haemodynamic compromise

Question 8

What are some causes of sinus tachycardia?

Answer 8

Physiological:

• anxiety
• fever
• hypotension
• anaemia

Drugs

Question 9

What is the treatment of sinus tachycardia?

Answer 9

Treat the cause

Beta-blockers

Question 10

What is the treatment for atrial ectopic beats?

Answer 10

• generally no treatment
• avoid stimulants e.g. caffeine, cigarettes
• beta-blockers may help

Question 11

What are the possible mechanisms of SVT?

Answer 11

• AV nodal re-entry
• accessory pathway
• atrial ectopic

Question 12

What is the acute management of SVT?

Answer 12

Increase vagal tone (manoeuvres)
Slow conduction at AVN
–> IV adenosine/verapamil

Question 13

Give some examples of vagal manoeuvres for infants, children and adults

Answer 13

Infants –> ice water to face
Children –> blow through straw (valsalva), carotid massage
Adults –> breath holding, carotid massage, cough, NG tube, gag reflex

Question 14

What is the chronic management of SVT?

Answer 14

• Avoid stimulants
• Electrophysiological study + radio frequency ablation –> first line in young symptomatic patients
• Beta-blockers e.g. propranolol, atenolol

Question 15

What is 1st degree AV block?

Answer 15

PR interval longer than normal –> (> 0.2 seconds)

- not really ‘block’, QRS follows every P wave but takes longer

Question 16

What is the management of 1st degree AV block?

Answer 16

No treatment

Long term follow up as may develop into more serious block over time

Question 17

What is 2nd degree AV block?

Answer 17

Intermittent dropped beats:

Mobitz I and II

Question 18

What is Mobitz I?

Answer 18

Progressive lengthening of thePR interval –> eventual dropped beat

Question 19

What is Mobitz II?

Answer 19

Usually 2:1 or 3:1 dropped beats

Question 20

What is the management of Mobitz II?

Answer 20

Permanent pacemaker

–> may progress to 3rd degree block

Question 21

What is 3rd degree AV block?

Answer 21

No APs from the SA node get through the AV node

–> no link between P waves and QRS complexes

Question 22

What is the management of 3rd degree AV block?

Answer 22

Ventricular pacing

Question 23

What are the ventricular arrhythmias?

Answer 23

• ventricular ectopics or premature ventricular complex (PVC)
• ventricular tachycardia
• ventricular fibrillation
• asystole

Question 24

What are some causes of ventricular ectopics?

Answer 24

• structural: LVH, HF, myocarditis
• metabolic: electrolytes
• may be a marker of inherited cardiac condition

Question 25

When should ventricular ectopics be investigated further?

Answer 25

If they are worse on exercise

Question 26

What are the management options for ventricular ectopics?

Answer 26

Beta-blockers

Ablation of focus

Question 27

What are some causes of VT (broad complex tachycardia)?

Answer 27

Mostly significant heart disease e.g. coronary artery disease, previous MI
Electrolytes
Drugs that prolong QT e.g. sotalol

Rarer causes: cardiomyopathy, inherited long QT, Brugada syndrome

Question 28

How does VT usually present?

Answer 28

May be stable but usually haemodynamically compromised

• -> large, sustained reduction in BP
• -> life threatening

Question 29

What are some of the ECG findings in VT?

Answer 29

• QRS rapid, wide and distorted
• T wave large with deflections opposite QRS
• ventricular rhythm regular
• P waves not visible
• PR not measurable

Question 30

What is the acute management of VT?

Answer 30

Direct current cardioversion (DCCV) if unstable
If stable, consider pharmacological cardioversion but prepare for DCCV
–> amiodarone

Look for causes and treat

Question 31

What is the long term management of VT?

Answer 31

Correct cause if possible e.g. revascularisation, HF management
Implantable cardiac defibrillators (ICD) if life threatening
VT catheter ablation

Question 32

Are AADs used in the long term management of VT?

Answer 32

No - ineffective and associated with worse outcomes

Question 33

What is ventricular fibrillation?

Answer 33

Chaotic ventricular electrical activity

–> heart loses the ability to function as a pump

Question 34

What is the management of ventricular fibrillation?

Answer 34

CPR and defibrillation

Question 35

Which ECG changes might be seen in hypokalaemia?

Answer 35

• small T waves
• ST depression
• prolonged QT
• prominent U waves

Question 36

Which ECG changes might be seen in hyperkalaemia?

Answer 36

• tall tented T waves
• broad QRS
• absent/flat P waves