QuestionSBA
QuestionChoice
Flecainide is classically used to cardiovert patients who have acutely gone into atrial fibrillation. It has an emerging role in the management of SVT; however would still not be used before attempting vagal manoeuvres. It is contraindicated if there is known structural heart disease
33290
c
Flecainide
QuestionChoice
The first line treatment that should be attempted in patients with SVT to cardiovert back to sinus rhythm is vagal manoeuvres. These include the Valsalva manoeuvre (in practice, this is often getting the patient to blow into a closed syringe) or carotid massage
33288
a
Vagal manoeuvres
QuestionChoice
Amiodarone is another pharmacological agent that can produce cardioversion. It would be given to patients who become unstable (ie. show adverse features) with their tachycardia. Adverse features include evidence of heart failure, myocardial ischaemia, shock or syncope
33291
d
Amiodarone
QuestionChoice
Adenosine 6mg IV is the first line pharmacological agent for cardioversion and would be the next course of action to consider if vagal manoeuvres were not successful
33289
b
Adenosine
QuestionChoice
Atropine is used in the acute management of bradycardia, not tachycardia, and would not be recommended for use in acute SVT
33292
e
Atropine
Concept
Chapter
# Summary

Supraventricular Tachycardia (SVT) is an umbrella term for several arrhythmias originating above the ventricles, including AV re-entry tachycardia and AV nodal re-entry tachycardia. Atrial fibrillation, atrial flutter and sinus tachycardias are all technically SVTs but are usually considered separately. Emergency treatment of SVT if the patient is stable involves vagal manoeuvres then administering adenosine if these are not successful. If the patient is unstable, cardioversion should be attempted with a synchronised DC shock.

# Definition
 
A Supraventricular Tachycardia (SVT) is any rhythm with a fast heart rate (over 100bpm) that originates from anywhere in the heart above the level of the Bundle of His. Unless there is aberrant conduction (e.g. bundle branch block), these will be narrow complex (i.e. QRS width is less than 120ms).
 
Sinus tachycardia, Atrial Fibrillation, Atrial Flutter, AV Re-entry Tachycardia (AVRT) and AV Nodal Re-entry Tachycardia (AVNRT) are examples of SVTs. Sinus tachycardia, Atrial Fibrillation and Atrial Flutter are considered separately and have different emergency management.
 
[lightgallery]
 
# Management 

**Unstable patients**
 
Patients with any of the following adverse features should be treated with a synchronised DC shock, which can be repeated if unsuccessful:

- Shock
- Syncope
- Heart Failure
- Myocardial Ischaemia (usually presenting as chest pain)

Patients who are conscious require sedation or anaesthesia prior to attempting cardioversion.

**Stable patients**

Patients with no adverse features should be treated initially with vagal manoeuvres, e.g. carotid sinus massage or the Valsalva manoeuvre (get the patient to blow into a 10ml syringe for 15-20 seconds)

If this fails, the next step is giving IV Adenosine 6mg, following this with 12mg then 18mg boluses if the previous one is unsuccessful. 

This should be done with continuous ECG monitoring.

If adenosine fails to terminate the SVT, verapamil or a beta-blocker could be tried, with DC cardioversion also an option if medical treatment is unsuccessful.

**Further information on Adenosine**
 
- Adenosine is a medication that works by temporarily blocking conduction through the AV node
- It is given as a rapid IV bolus over 1-3 seconds 
- Prior to administration, patients should be warned that they may experience difficulty breathing, chest tightness and flushing
- Because of the risk of bronchospasm, patients with asthma should not be given adenosine (verapamil should be used instead)
- In patients with a central line, a reduced dose of 3mg should be given

# References

[UK Resuscitation Council Adult Tachycardia Algorithm](https://www.resus.org.uk/sites/default/files/2021-04/Tachycardia%20Algorithm%202021.pdf)

[BNF Treatment Summary - Arrhythmias](https://bnf.nice.org.uk/treatment-summaries/arrhythmias/#paroxysmal-supraventricular-tachycardia)
2032
Picture
382
Supraventricular tachycardia.jpg
images/dio7r8pf1639016760443.jpg
images/dio7r8pf1639016760443_256.jpg
images/dio7r8pf1639016760443_512.jpg
NQgGBYCKp5iFeIhvl2eHjLCIcgu5
Topic
35
Cardiology
2675
Emergency Management of Supraventricular tachycardia
Topic
35
Cardiology
6658
A 29 year old man presents to the emergency department (ED) with palpitations and vomiting. His ECG shows supraventricular tachycardia (SVT) at a rate of 170 beats per minute. The patient is stable with no adverse features.

What is the first line treatment for this patient?
a