Intravenous antiarrhythmic drugs: newer aspects of therapy

The use of the intravenous form of antiarrhythmic drugs from the perspective of prophylaxis, urgency of therapy, and rapid assessment of effectiveness is reviewed. Examples of clinical relevance for each of these 3 variables are used to illustrate the relevance of these approaches. 1) In the human model of acute myocardial infarction, prophylaxis with lidocaine is proved and is safe, with toxicity minimized when accurate determinations of blood levels of drug are readily available. 2) When reversion is unsuccessful and ventricular response cannot be controlled with conventional therapy, rapid supraventricular tachyarrhythmias will often normalize in response to intravenous verapamil therapy, a calcium-blocking agent soon available for clinical use. 3) A long-term outpatient antiarrhythmic drug program guided by target blood levels can be defined rapidly by intravenous administration of drug; this approach enhances safety and simplifies the definition of an ongoing antiarrhythmic program. Disopyramide responsiveness can be defined using this technique.