A Textbook of Clinical Pharmacology and Therapeutics

provides a simple and practical algorithm for the manage-
ment of tachydysrhythmias in general.
Catheter ablation therapy is now possible for supraventric-
ular tachycardias, atrial flutter and fibrillation. Advice from a
consultant cardiac electrophysiologist should be sought
regarding the suitability of a patient for this procedure.

Ventricular dysrhythmias

Ventricular ectopic beats: Electrolyte disturbance, smoking,
alcohol abuse and excessive caffeine consumption should be
sought and corrected if present. The only justification for
treating patients with anti-dysrhythmic drugs in an attempt to
reduce the frequency of ventricular ectopic (VE) beats in a
chronic setting is if the ectopic beats cause intolerable palpita-
tions, or if they precipitate attacks of more serious tachydys-
rhythmia (e.g. ventricular tachycardia or fibrillation). If
palpitations are so unpleasant as to warrant treatment despite

the suspicion that this may shorten rather than prolong life, an

oral class I agent, such as disopyramide, may be considered.

Sotalolwith its combination of class II and III actions is an

alternative, although a clinical trial with the D-isomer (which

is mainly responsible for its class III action) showed that this

worsened survival (the ‘SWORD’ trial).

In an acute setting (most commonly the immediate after-

math of myocardial infarction), treatment to suppress ventricu-

lar ectopic beats may be warranted if these are running

together to form brief recurrent episodes of ventricular tachy-

cardia, or if frequent ectopic beats are present following car-

dioversion from ventricular fibrillation. Lidocaineis used in

such situations and is given as an intravenous bolus, followed

by an infusion in an attempt to reduce the risk of sustained

ventricular tachycardia or ventricular fibrillation.

Ventricular tachycardia: This is covered in Figure 32.3 (manage-

ment of tachydysrhythmias). In the longer term, consideration

222 CARDIAC DYSRHYTHMIAS

• Support ABCs; give oxygen; cannulate a vein


• Monitor ECG, BP, SpO 2


• Record 12-lead if possible, if not record rhythm strip


• Identify and treat reversible causes

Is patient stable?

Signs of instability include:

1. Reduced conscious level 2. Chest pain


2. Systolic BP 90 mmHg 4. Heart failure
   (Rate related symptoms uncommon at less
   than 150 beats min^1 )

Unstable

• Amiodarone 300 mg IV over 10–20
  min and repeat shock; followed by;


• Amiodarone 900 mg over 24 h

Synchronised DC shock*

up to 3 attempts

Stable

Narrow

Is QRS regular? Is rhythm regular?

Broad

Irregular

Irregular

Regular

Regular

Is QRS narrow ( 0.12 sec)?

Seek expert help

Possibilities include:

• AF with bundle branch block
  treat as for narrow complex


• Pre-excited AF
  consider amiodarone


• Polymorphic VT (e.g.
  torsades de pointes – give
  magnesium 2 g over 10 min)

If ventricular tachycardia

(or uncertain rhythm):

• Amiodarone 300 mg IV
  over 20–60 min; then 900 mg
  over 24 h

If previously confirmed SVT

with bundle branch block:

• Give adenosine as for regular
  narrow complex tachycardia

*Attempted electrical cardioversion is

always undertaken under sedation

or general anaesthesia

• Use vagal manoeuvres


• Adenosine 6 mg rapid IV bolus;
  if unsuccessful give 12 mg;
  if unsuccessful give futher 12 mg.


• Monitor ECG continuously

Irregular narrow complex

tachycardia

Probableatrial fibrillation

Control rate with:

• β-Blocker IV, digoxin IV, or
  diltiazem IV
  if onset 48 h consider:


• Amiodarone 300 mg IV 20–60
  min; then 900 mg over 24 h

Seek expert help

No

Yes

Normal sinus rhythm

restored?

Probable re-entry PSVT:

• Record 12-lead ECG in
  sinus rhythm


• If recurs, give adenosine
  again & consider choice of
  anti-dyshythmic prophylaxis

Possibleatrial flutter

• Control rate (e.g. β-Blocker)

Figure 32.3:Scheme for the management of tachydysrhythmias. (Adapted with permission from the European Resuscitation Council
Guidelines, 2005).