1. Link Nurse Study Day Supraventricular Tachycardia
Leila Rittey
Paediatric Cardiology Registrar

3. Cardiac Cycle (Electrical)

4. What does the ECG mean?

5. Normal Paediatric ECG

6. SVT Tachycardia that originates from above the ventricles
Several different subtypes including Wolff- Parkinson White, concealed atrioventricular reentry tachycardia (AVRT), atrioventricular nodal reentry tachycardia (AVNRT), atrial tachycardia
Narrow complex tachycardia
Normally safe (some WPW and prolonged undetected SVT (neonatal) only real differences)

7. Example of accessory pathway

8. Narrow v’s Broad Complex Tachycardia
Narrow Complex Tachycardia
Broad Complex Tachycardia

9. Signs/symptoms SVT
Neonate – poor feeding, not right, none (can present in failure if been in SVT long time)
Young child – fluttering (sometime will say tummy), not right, pale, parents feel fast heart
Older child – palpitations, pale, chest discomfort

10. Management of SVT
Vagal manouvres – neonate – dunk in ice water at least 10 seconds, it will feel very long
- toddler – hold upside down
- older – handstands, blowing into a syringe, “squeeze like you are having a poo!”
Medical – adenosine – breaks cycle
- antiarrythmics – propranolol/ atenolol, flecainide, amiodarone – stabilises myocardium
Electrical – if shocked – shock them (1-2J/kg)

11. Management of SVT in Community
If known children/family will generally have some ideas re vagal manouvres
Don’t worry – try vagal manouvres
If well (and known about) can see if it will stop on own (don’t wait longer than 30mins)
If ongoing take to ED (no need for ambulance if well)
If unwell - 999

12. School Information Leaflet

13. Treating SVT in hospital
Children generally tolerate SVT really well
Don’t panic
ABCDE assessment
If clinically well – try vagal manoeuvres
Then adenosine – more info next slide
If SVT stops (even for 1 second) the adenosine has worked!!!
If goes back into SVT – speak to cardiology and we will likely commence antiarrhythmic and retry adenosine later (around 1hr if well)

14. Giving adenosine
Give a proper dose - starting dose 200 micrograms/kg, if unsuccessful increase dose up to 300 then 500micrograms/kg.
Adenosine needs a big flush – generally 20ml
Adenosine needs to be given quickly via a 3 way tap (broken down by red blood cells)
Always record a rhythm strip when giving adenosine – it gives us a lot of information
Very rarely can cause VF – always give in a room with a defib available

15. SVT – shocked child Crash team
If has IV access can quickly try adenosine whilst setting up defibrilator
DC cardioversion – synchronised 1J/kg, if unsuccessful 2J/kg
Intubation – in itself this can sometimes help revert to sinus rhythm
May require amiodarone – only after discussions with paediatric cardiology

16. Case Study 1 12yr old girl Went to GP with palpitations
GP noted HR 260 -> ED
ECG - SVT
ED gave adenosine -> sinus rhythm
Baseline ECG………

18. Diagnosis?? Very short PR interval Delta wave ST segment changes
Wolff Parkinson White

19. Management
3 options
1) Do nothing and observe – WPW can have a risk of sudden death (1 per 1000 per year)
2) Start medication – doesn’t reduce risk of sudden death in WPW
3) Ablation (leeds congenital hearts website have video’s explaining – good to signpost people to prior to cardiology oupatients)

20. Management continued
Patient and parents decided to not commence medication but to be referred for discussions re ablation
Has had ablation and currently doing well 6 months after with a normal baseline ECG (no delta wave!!!)
If still normal ECG 1 yr after and no palpitations would be discharged

21. What is ablation Catheter procedure
Insert wires into the heart (via lines in groin and 1 in arm) to find the area causing SVT
By using (normally) heat they can burn the area turning it into scar tissue
Around 90% change of cure

22. Case Study - 2 17 day old baby
Presented to local hospital with swollen testicle
Noted to have HR
Taken to resus – ECG………

23. ECG

24. Clinical state
Local team tried adenosine x2 – reported as not working…
Lethargic
Apnoeic – needing bagging
Called me

25. Further discussion
Adenosine had terminated SVT but came back within seconds
Pulses weak, unrecordable blood pressure
Currently bagging as inconsistent respiratory effort
BABY IS SHOCKED

26. Management
DC cardioversion – 2J/kg (defib wouldn’t give less) – no effect
2nd DC cardioversion – 2J/kg – no effect
Local team reassessed – pulses improved, BP now acceptable
Intubated
Commenced amiodarone – load then maintenance
Embrace to transfer to LGI

27. Management continued On arrival to PICU – still in SVT
500micrograms/kg adenosine trialled – briefly reverted to sinus rhythm but quickly back to SVT
ECHO – impaired function
Cardiovascularly stable
Retried adenosine after 4hrs – no effect
Further half load of amiodarone 8hrs after arrived in LGI
Reverted to sinus rhythm around 14hrs after arrival
Function improved over next few days – normal
Discharged week later on oral amiodarone

28. Take home points SVT generally not dangerous
Adenosine – 3 way tap, big flush (min 10ml – neonate only)
Always record rhythm strip when giving adenosine
Adenosine only breaks SVT doesn’t necessarily keep it away
May need antiarrhythmic and time…
If in doubt, call us. We aren’t too mean 