Adult Medical Emergency Handbook - Scottish Intensive Care Society

i
• Maintenance anti-arrhythmic therapy following restoration
of sinus rhythm depends on the arrhythmia substrate for SVT
prophylaxis. VT prophylaxis centres around the use of betablockers
and/or amiodarone. Some patients may require ICD
implantation. Long-term management of these patients should
always be discussed with a consultant cardiologist.
• Most anti-arrhythmic drugs can cause sinus bradycardia or AV
block. For patients with impaired LV function, beta-blockers
should be introduced at a low dose (e.g bisoprolol 1.25mg daily)
and titrated gradually. Amiodarone is effective for VT treatment
and prophylaxis in these patients. Class Ic drugs such as
flecainide and propafenone are contraindicated in heart
failure/LV impairment.
• Overdrive pacing may be considered for resistant or recurrent
ventricular arrhythmias.
VT or VF are commonly triggered within the first 48 hours of acute
MI. In this situation recurrence after the acute event is uncommon
and no specific prophylaxis is needed. VT or VF occurring more
than 48 hours after acute MI is more sinister; this may indicate the
development of a chronic arrhythmia substrate. These patients
need assessment with a view to revascularisation and either antiarrhythmic
drug treatment or an ICD.
Do not hesitate to seek a senior cardiology opinion in the case
of troublesome dysrhythmias - ‘cocktails’ of anti-arrhythmics
cause more problems than they solve.
TORSADE-DE-POINTES TACHYCARDIA
Characterised by rapid, broad QRS complexes twisting around the
baseline giving the appearance of changing QRS morphology and
axis. It is a form of polymorphic VT and can be mistaken for VF. It
is often self terminating and recurrent. Its recognition is important
because the aetiology and treatment differs from monomorphic VT.
Diagnosis
Consider Torsade when the following are present:
• Polymorphic VT.
• Prolonged QT interval.
• Initiation of tachycardia with long-short coupling intervals.
adult medical emergencies handbook | NHS LOTHIAN: UNIVERSITY HOSPITALS DIVISION | 2009/11
123