SupraVentricular Tachycardia

Question 1

What is SVT?

Answer 1

Tachycardia originating from the atria

Question 2

How does the electrical current usually travel through the heart?

Answer 2

Sinoatrial Node
Through the atria
Atrioventricular Node
Left and Right Bundle Branches (2 branches on the left)
Purkinjee Fibres
Ventricular Contraction

Question 3

What type of tachycardia is an SVT?

Answer 3

A narrow complex tachycardia
QRS <0.12 seconds

Question 4

What is sinus tachycardia?

Answer 4

Not classed as an SVT
There is normal P, QRS and T waves.

Question 5

What causes sinus tachycardia?

Answer 5

Caused by underlying pathology like sepsis

Question 6

How is sinus tachycardia treated?

Answer 6

By treating the underlying cause

Question 7

What are the 3 types of supra ventricular tachycardia?

Answer 7

1. Atrioventricular nodal re-entry tachycardia (most common)
2. atrioventricular re-entry tachycardia - EG WPW syndrome
3. Atrial tachycardia

Question 8

What is the rate of the atria in atrial flutter?

Answer 8

The rate of the atria sits at 300bpm. The QRS occurs at regular intervals depending on how often conduction travels through the ventricles.

Question 9

What’s the most common type of atrial flutter?

Answer 9

2:1

Question 10

When will SVT cause a broad complex QRS?

Answer 10

ONLY if Theres an associated bundle branch block.

Question 11

What is wolf-parkinson-white syndrome?

Answer 11

An extra electrical pathway connecting the atria and ventricles

Question 12

What is the extra pathway called in WPW syndrome?

Answer 12

Bundle of Kent

Question 13

What are the ECG chances in WPW syndrome?

Answer 13

Short PR <0.12 seconds
Wide QRS >0.12
Delta wave (slurred upstroke on the QRS complex)

Question 14

What is the definitive management of WPW syndrome?

Answer 14

Radiofrequency ablation

Question 15

What is the management for stable SVT?

Answer 15

1. valsalva manœuvre
2. carotid sinus massage
3. adenosine
4. electrical cardioversion

Question 16

When is adenosine contraindicated?

Answer 16

Asthma
COPD
heart failure
Heart block
Severe hypotension

Question 17

What is given if adenosine is contraindicated?

Answer 17

Verapamil

Question 18

How is adenosine given?

Answer 18

Through a large bore proximal cannula as a rapid bolus.

6mg then 12mg then 18 mg. Followed by a flush.

Question 19

What is the side effects of adenosine

Answer 19

Half life <10 seconds
Often causes a brief systole/bradycardia before normal sinus rhythm is restored
warn patients of impending doom

Question 20

What are the signs of unstable SVT?

Answer 20

Tachypnoea
Chest pain
Heart failure
Hypotension
Poor perfusion

Question 21

What is the treatment of complicated SVT?

Answer 21

1. synchronised cardio version

Question 22

when must synchronised cardio version be done?

Answer 22

Whenever a patient has a pulse.

So the shock is delivered on an R wave and not on a T wave (which can cause ventricular fibrillation)

Question 23

What is the long term management of SVT?

Answer 23

Medication: Beta-blockers, calcium channel blockers or amiodarone
Radiofrequency ablation

Question 24

What can RFA cure?

Answer 24

SVT
WPWS
AFlutter
AF

Question 25

What type of SVT is wolf Parkinson white syndrome?

Answer 25

Atrioventricular re-entry tachycardia.

Question 26

When might Left or right axis deviation be seen with WPW syndrome?

Answer 26

Left axis deviation - if theres a right sided accessory pathway. (most likely)
Right axis deviation - if theres a left sided accessory pathway.