Treatment of Stable VT

Assuming the underlying rhythm is VT and that the patient is stable, first-line treatment is conventionally amiodarone (Resus Council UK guidance).

However, amiodarone is poorly effective in the treatment of acute VT. In a small, retrospective study of 33 patients given 150 mg amiodarone it had only a 29% success rate after 20 minutes. Four patients deteriorated and 55% of the patient group ultimately required electrical treatment [9]. A more recent study of 41 patients substantiated these findings: only 15% of the patient group cardioverted with a bolus dose of 300 mg amiodarone after 20 minutes and 17% of patients deteriorated [10].

Sotalol appears more effective One cross-over study showed a 69% success rate in the treatment of stable VT (compared with lignocaine, which was the ALS recommendation at that time) [11]. The AHA 2020 Adult Tachycardia algorithm suggests using a dose of 100mg (1.5mg/kg) over 5 minutes.

Procainamide has class 2a evidence supporting its usage in this situation but is slow to work. A recent RCT published in 2017 comparing procainamide to amiodarone in the haemodynamically stable patient with acute monomorphic VT procainamide was more efficacious in terminating arrhythmia, and was associated with less major cardiac adverse events. The AHA 2020 Adult Tachycardia algorithm suggests using a dose of 20-50 mg/min until:

• Resolution of arrhythmia
• Maximum dose 17 mg/kg given
• Adverse events:
• Hypotension develops
• QRS duration increases >50%

If the arrhythmia has been successfully treated, adverse events have not occurred & maximum dose not reached, a maintenance infusion of 1-4 mg/min can be commenced.

Both sotalol and procainamide have the potential to prolong the QT interval and are best avoided in patients who already have QT prolongation on ECG.

DC cardioversion is reasonable as first-line treatment of stable VT.

Learning bite

Amiodarone is poorly effective in the treatment of stable VT. Consider electrical cardioversion or soltalol instead.