Arrhythmias – Supraventricular Tachycardia (SVT) – Atrial Fibrillation

Question 1

Define supraventricular tachycardia (SVT) arrhythmia

Answer 1

An abnormality of the heart’s rate or rhythm, originating in the atria

Question 2

What is Bradycardia/Bradyarrhythmia defined as?

Answer 2

< 60bpm

Question 3

What is Sinus Bradycardia?

Answer 3

Caused by Sinus pauses, Sick Sinus Syndrome, Ischaemia and Infarction

Question 4

What is Tachycardia/Tachyarrhythmia defined as?

Answer 4

> 100bpm

Question 5

What are Supraventricular Tachyarrhythmias?

Answer 5

Occurring in the atria/above the ventricles

Question 6

What are the types of SVT?

Answer 6

Atrial Fibrillation, Atrial Flutter, AVRT and AVNRT

Question 7

What are types of AFib?

Answer 7

• Paroxysmal AF
• Persistent AF
• Longstanding persistent AF
• Permanent AF

Question 8

What is paroxysmal AF?

Answer 8

Intermittent arrhythmias lasting minutes to days

Question 9

What is persistent AF?

Answer 9

Lasts longer than 7 days, or less when treated

Question 10

What is longstanding persistent AF?

Answer 10

Continuous AFib for a year or longer

Question 11

What is permanent AF?

Answer 11

Severe AFib present all the time, no attempts to restore normal heart rhythm made

Question 12

What is the pathophysiology of AFib?

Answer 12

• Characterised by abnormal electrical activity within the atria, causing them to fibrillate and not pump blood effectively
• There can be pooling of blood which can lead to thromboembolic events
• Most common cardiac rhythm disorder

Question 13

What is AFib most caused by?

Answer 13

cardiac remodelling (changes in the structure of the heart) in response to disease/damage

Question 14

What does AFib often show on presentation?

Answer 14

asymptomatic

Question 15

What shows on an ECG for AFib?

Answer 15

irregularly irregular pulse without p waves

Question 16

What are symptoms for AFib?

Answer 16

Palpitations
Chest Pain
Shortness of Breath/Dyspnoea
Dizziness/syncope

Question 17

What are signs of AFib?

Answer 17

Irregularly irregular pulse
Hypotension
Evidence of heart failure

Question 18

What are risk factors for AFib?

Answer 18

Advancing age
Male sex
Family history
Hypertension
Heart conditions
Alcohol consumption
Smoking
Thyroid disorders
Chronic kidney disease (CKD)

Question 19

What are complications of AFib?

Answer 19

Ischaemic Stroke
Heart failure
Cardiogenic Shock

Question 20

What are investigations for AFib?

Answer 20

• ECG
• Bloods
• CXR
• Transoesophageal Echocardiogram

Question 21

What is seen on an ECG for AFib?

Answer 21

• “Irregularly Irregular” rate and no distinguishable p waves
• Fibrillatory waves may be present or absent

Question 22

What is seen in bloods results for AFib?

Answer 22

To determine causes:
- FBC for infection and electrolyte imbalances
- TFTs for hyperthyroidism
- Cardiac biomarkers and BNP for cardiac disease

Question 23

Why is a CXR done?

Answer 23

Check for abnormality

Question 24

Why is a Transoesophageal Echocardiogram done?

Answer 24

To assess for cardioversion

Question 25

How long is acute AFib presentation?

Answer 25

<48hrs after symptoms

Question 26

What type of patients are usually seen for acute AFib?

Answer 26

Patients are usually younger and present with severe symptoms

Question 27

What are acute AFib symptoms?

Answer 27

Rapid pulse (>150bpm) Low BP (Systolic BP < 90mmHh) Loss of consciousness (Syncope) Chest Pain SOB (Dyspnoea)

Question 28

What are the aims for treating acute AFib?

Answer 28

- Treat underlying conditions which may cause AF (e.g. MI, Pneumonia) - Control Ventricular rate (Using either 1st or 2nd line agents)

Question 29

What 2 treatments would you consider for acute AFib?

Answer 29

- anticoagulants - DC or drug cardioversion

Question 30

Describe anticoagulant treatment for acute AFib

Answer 30

Heparin whilst the patient is assessed and then oral anticoagulation after AFib is confirmed

Question 31

Describe DC or drug cardioversion treatment for acute AFib

Answer 31

- Use DC cardioversion in an acute setting - performed in ITU setting with sedation - shocked at 200J initially, if unsuccessful, try 2 further attempts at 360J - Thrombi are a contraindication for cardioversion

Question 32

What are the aims for treating chronic AFib?

Answer 32

- Identify and treat reversible causes - Conduct echo to rule out structural heart disease - Control Ventricular rate or rhythm

Question 33

What are the 1st line rate control options for treating chronic AFib?

Answer 33

1st Line - Beta Blocker OR Ca2+ Blocker (Using both is contraindicated; causes heart block) - BB is generally preferred (Atenolol, Bisoprolol, Carvedilol etc.)

Question 34

What are the 2nd line rate control options for treating chronic AFib?

Answer 34

2nd Line – Same as 1st line but add Digoxin or Amiodarone - Digoxin cannot be used as the sole treatment for AF

Question 35

What are the rhythm control options for treating chronic AFib?

Answer 35

- Flecainide - Amiodarone - Electrical Cardioversion - Catheter Ablation

Question 36

What is flecainide contraindicated in?

Answer 36

Contraindicated in LV dysfunction, LV hypertrophy

Question 37

What can amiodarone cause?

Answer 37

Can cause thyrotoxicosis; Excess T3 or 4

Question 38

Which type of patients is catheter ablation usually used in?

Answer 38

In younger patients with failed rhythm control using other options

Question 39

What is used to assess need for anticoagulation?

Answer 39

CHA2DS2-VASc

Question 40

What is used to assess bleeding risk?

Answer 40

ORBIT

Question 41

What does a CHA2DS2-VASc score of 0 mean?

Answer 41

Risk is low, No AC therapy needed

Question 42

What does a CHA2DS2-VASc score of 1 mean?

Answer 42

Risk is low-moderate, AC therapy considered

Question 43

What does a CHA2DS2-VASc score of 2+ mean?

Answer 43

Risk is moderate or high, AC therapy recommended

Question 44

What does an ORBIT score of 0-2 mean?

Answer 44

Risk is low, 2.4 bleeds per 100 patient-years (unit of measurement for risk)

Question 45

What does an ORBIT score of 3 mean?

Answer 45

Risk is medium, 4.7 bleeds per 100 patient-years

Question 46

What does an ORBIT score of 4-7 mean?

Answer 46

Risk is high, 8.1 bleeds per 100 patient-years

Question 47

What does CHA2DS2-VASc stand for?

Answer 47

C- Congestive HF +1 H- Hypertension +1 A2- Age 75+ +2 D- DM+1 S2- Previous stroke, TIA or thromboembolism +2 V- Vascular disease +1 A- Age 65-74 +1 Sc- Sex category (female) +1

Question 48

What does ORBIT stand for?

Answer 48

O - Older (75+) +1 R- Reduced Hb +2 B- Bleeding history +2 I- Insufficient kidney function +1 T- Treatment with antiplatelet agent +1

Question 49

What are 2 types of DOACs (Direct Oral Anticoagulants)?

Answer 49

Factor Xa inhibitors Thrombin inhibitors

Question 50

What are examples of factor Xa inhibitors?

Answer 50

rivaroxaban, apixaban

Question 51

What is an example of thrombin inhibitors?

Answer 51

dabigatran

Question 52

What is preferred DOACs or warfarin?

Answer 52

DOACs

Question 53

Why are DOACs preferred over warfarin?

Answer 53

- DOACs don’t require monitoring of INR (International normalised ratio; used to measure length of time to clot) unlike warfarin (Need to maintain a level of INR in an individual on warfarin) - DOACs have less drug interactions - DOACs have standardised dosing

Question 54

What are disadvantages of DOACs?

Answer 54

- DOACs are less easily reversible; hard to stop the effects of DOACs if patient is bleeding - DOACs not recommended for use when structural heart disease present

Question 55

Summarise the treatment for paroxysmal AFib

Answer 55

- 1st line – Sotalol/Bisoprolol (Beta Blockers) In youth, use Flecainide/Verapamil, avoid in elderly (negatively ionotropic) - 2nd line – Amiodarone - 3rd line – Digoxin; useful in LV dysfunction as it is positively ionotropic - Consider Anticoagulants - Consider DC Cardioversion + Amiodarone