Emergency Medicine

DC CARDIOVERSION

474 Practical Procedures

COMPLICATIONS

1 Malposition: extrathoracic (obvious on CXR as it runs up external to chest

wall), or intrathoracic but extrapleural (not obvious on CXR, but exceed-

ingly painful!).

2 Haemothorax (may even require thoracotomy if does not settle).

3 Subcutaneous emphysema.

4 Re-expansion pulmonary oedema.

5 Trauma to heart, liver, lung or spleen.

6 Local nerve injury (e.g. long thoracic nerve).

7 Infection, eit her sk in site or empyema.

DC CARDIOVERSION

INDICATIONS

1 Emergency treatment of a haemodynamically ‘unstable’ patient (chest pain,

confusion, hypotension, heart failure) with a tachyarrhythmia.

2 Elective treatment of a stable patient with a tachyarrhythmia (e.g. atrial

fibrillation [AF]) with onset within previous 24–48 h.

CONTRAINDICATIONS

1 Sinus tachycardia.

2 Multifocal atrial tachycardia.

3 Arrhythmias due to enhanced automaticity in digoxin toxicity (risk of resist-

ant ventricular fibrillation [VF]).

4 Reversion of AF of >48 h duration (risk of embolism).

TECHNIQUE

1 Use procedural sedation such as low-dose propofol 0.5–1.0 mg/kg, or fenta-

nyl 0.5 g/kg plus midazolam 0.05 mg/kg titrated to effect for a conscious

patient undergoing elective cardioversion (less if shocked).

2 Set the defibrillator to ‘synchronous’ mode so that the shock is delivered with

the R wave of the ECG to reduce the risk of precipitating VF.

3 Energy requirements are generally less than those for defibrillating VF.

(i) Atrial flutter (and paroxysmal supraventricular tachycardia

[SVT] other than AF): start with 50–100 J biphasic.

(ii) Monomorphic VT and AF: use 120–150 J biphasic.