Narrow Complex Tachycardia

Question 1

Treatment for AF/SVT deteriorating to cardiac arrest

Answer 1

Synch cardiovert at 200J

Question 2

Unstable/deteriorating SVT (4)

Answer 2

1. Inadequate perfusion/shock
2. ALOC or unconscious
3. Ischaemic chest pain
4. APO

Question 3

Modified Valsalva

Answer 3

Lay semi-recumbent
Forced expiration 15s
Immediately lay supine, raise legs for 15s
Return to semi-recumbent

Question 4

Rationale for Valsalva

Answer 4

Forced expiration increases intrathoracic pressure, decreasing venous return and CO. Carotid baroreceptors detect this and increase sympathetic drive to correct decreased venous return leading to increased HR and vasoconstriction.

On cessation of forced expiration, the sudden increase in venous return is detected by baroreceptors which then increase vagal innervation - promoting muscarinic activity at AV node. This slows electrical activity, interrupting re-entrant circuit.

Question 5

SBP required for Valsalva

Answer 5

> 90

Question 6

Attempts and intervals for Valsalva

Answer 6

3 attempts, 2mins apart

Question 7

Adenosine for stable SVT

Answer 7

Adenosine 6mg IV.
Rpt 12mg after 2mins.
Rpt 12mg after 2 mins.
(Max 30mg)

Question 8

Unstable SVT treatment

Answer 8

Synch cardiovert at 150J.
Repeat once if required.
If unsuccessful, change pads to AP position and DCCS 200J.

Midaz 1-2mg + 50mcg Fentanyl IV for sedation/analgesia

Question 9

WPW pattern

Answer 9

Only visible in resting ECG.

Short PRI, slurred upstroke into QRS (delta wave), prolonged QRS.