Adult Medical Emergency Handbook - Scottish Intensive Care Society

ATRIAL FLUTTER
Characterised by rapid regular or irregular narrow QRS complexes with
a saw-tooth appearance to the baseline. A regular, narrow complex
(unless BBB pattern present) tachycardia of 150 bpm should be
suspected to be atrial flutter with a 2:1 block irrespective of whether or
not flutter waves are obvious on the ECG.
Management
• Carotid sinus massage/vagal manoeuvres may slow the ventricular
response revealing underlying flutter waves and assisting the diagnosis.
• Adenosine may also be used to help assist the diagnosis by
slowing AV conduction and revealing flutter waves. Rapid IV
bolus of 6mg followed by saline flush, up to 12mg IV a total
of twice at 1-2 minute intervals may be given if tolerated.
Do not use in asthmatics (bronchoconstriction) or those
taking dipyridamole, carbamazepine or with denervated
(transplanted) hearts (effects prolonged and potentiated).
Administration may be accompanied by flushing and/or chest
tightness but the half life is short (20 seconds) with clinical effects
resolving in about 2 minutes. WARN THE PATIENT. Always run
an ECG rhythm strip during administration. Adenosine is contraindicated
in 2nd or 3rd degree AV block.
• Atrial flutter tends to be sustained and does not respond readily to
AV node blocking drugs. Therefore, every patient with persistent
atrial flutter should be considered for early cardioversion.
• For immediate management consider using the management
guideline for atrial fibrillation.
• Note that IV Flecainide cardioversion should NOT be used for atrial
flutter. It can slow the flutter rate and cause a paradoxical rise in the heart
rate to >200bpm. (Increased rate of conduction through a-v node).
SUPRAVENTRICULAR TACHYCARDIA
Characterised by regular narrow QRS complexes.
Three types exist:
1. AV Node re-entry tachycardia. Usually presents in young adults.
Commoner in women. Usually no ‘P’ waves visible.
2. AV re-entry tachycardia (the tachycardia associated with WPW).
Also presents in young adults. Inverted ‘P’ waves may be seen
after the QRS and a pseudo-RBBB pattern in V1.
3. Atrial tachycardia due to enhanced automaticity in an atrial focus. ‘P’
waves visible before the QRS but with abnormal P wave morphology.
120 adult medical emergencies handbook | NHS LOTHIAN: UNIVERSITY HOSPITALS DIVISION | 2009/11