The indication for using a vasopressor such as epinephrine and/or vasopression is refractory ventricular fibrillation (VF that does not respond to counter-shock). In this case, administering agents that may be pro-arrhythmic would be a poor choice.

More therapeutic energy may be needed when a patient fails to respond at a lower level. However, in this case the patient responded well to each shock delivered. The problem was not refractoriness to the therapy. This patient kept having spontaneous re-induction.

Drugs such as lidocaine, procainamide, and amiodarone have been shown to increase the induction threshold for ventricular arrhythmias. With this in mind, use of such agents may make clinical sense. Issues such as onset of action, difficulty in establishing rapid blood levels, and whether or not ischemia is a component should be considered.

There are many clinical possibilities for chronic re-induction of arrhythmias. Some might include:

• on-going ischemia
• organic cardiac damage
• electrolyte imbalance

Practitioners should seek to find the underlying cause and correct the problem as quickly as possible in order to improve the patient's outcome.