The Effects of Procainamide:
Procainamide is effective in slowing the conduction in the atria, ventricles, and bundle of His Purkinje system. It does this by:
- Prolonging the PR intervals and QT intervals
- Slowing the refractory periods of the atria and ventricles
- Slowing the refractory period of the atrioventricular node
Procainamide Indications for Use:
It helps treat:
- Stable wide complex tachycardia of uncertain origin
- Stable monomorphic ventricular tachycardia with normal QT interval
- Atrial fibrillation with a rapid ventricular rate response in patients with Wolff-Parkinson-White (WPW) syndrome and recurrent ventricular fibrillation or pulseless ventricular tachycardia
Procainamide Precautions & Contraindications:
There are some contraindications for the use of procainamide. The ACLS team should be aware of any known sensitivity to procainamide or similar medications for the patient.
Digitalis toxicity may complicate already existing atrioventricular conduction depression. Other contraindications would include third degree heart block or pre-existing prolongation of the QRS complex and QT intervals. Procainamide should be avoided in patients with prolonged QT intervals and associated CHF.
Adult Dosage for Procainamide:
The use of procainamide is limited in ACLS for cardiac arrest, due to its requirement of slow infusion and its somewhat unknown effectiveness.
If used for recurrent ventricular fibrillation and pulseless ventricular tachycardia, 20 mg/min should be given via IV infusion to a total dose of 17 mg/kg. For supraventricular tachycardia, atrial fibrillation, and wide complex tachycardias of uncertain origin, procainamide should be administered at 20 mg/min via IV infusion to a total of 17 mg/kg. For maintenance, it can be administered at 1 to 4 mg/min titrated to desired effect and patient’s response.
The use of procainamide should be stopped if any of the following occurs:
- Arrhythmia suppression
- Onset of hypotension
- QRS complex widening by greater than 50% of pretreatment width
- Maximum dose of 17 mg/kg is reached