I47.0-2/I47.9
These tachycardias are usually ventricular. They are common in acute myocardial infarction. Check serum potassium level and correct if low.
MEDICINE TREATMENT
- Amiodarone, IV, 5 mg/kg infused over 30 minutes.
Follow with:
- Amiodarone, oral, 800 mg daily for 7 days.
- Then 600 mg daily for 3 days.
- Follow with a maintenance dose of 200–400 mg daily, depending upon clinical judgement. Consult specialist before instituting long-term (>1 week) therapy.
Precautions: - If on warfarin, halve the dose of warfarin and monitor INR closely, until INR is stable.
- Avoid concomitant digoxin.
- Monitor thyroid function every 6months as thyroid abnormalities may develop.
- Ophthalmological examination every 6 months.
OR
Only in haemodynamically stable patients:
- Lidocaine (lignocaine), IV, 50–100 mg (1–2 mg/kg) initially and at 5 minute intervals if required to a total of 200–300 mg.
Thereafter, for recurrent ventricular tachycardia only:
- Lidocaine (lignocaine), IV infusion, 1–3 mg/minute for 24–30 hours.
- Lidocaine will only terminate ± 30% of sustained ventricular tachycardias, and may cause hypotension, heart block or convulsions.
- For emergency treatment of ventricular tachycardia, DC cardioversion is first line therapy, even if stable.
In the absence of acute ischaemia or infarction, consider torsades de pointes, due to QT prolonging medicines.