Antifibrillatory drugs: the case for bretylium tosylate.

The preferred treatment for ventricular fibrillation (VF) refractory to maximal electrical defibrillation remains controversial, as evidenced by recent changes in the American Heart Association's treatment algorithm. To date there have been no published studies conclusively proving one mode of therapy to be superior to another. There is, however, an abundance of animal and clinical data suggesting that bretylium tosylate (BT) is the drug of choice in this setting. In animal studies BT has been shown to lower the canine defibrillation threshold, to facilitate conversion of hypothermia-induced ventricular fibrillation, and to effect spontaneous defibrillation. In 15 years of clinical use as a drug of last resort, and more recently as a first-line drug, BT has developed an impressive track record. Most of the clinical reports are uncontrolled and/or retrospective, but they share a central theme: BT is effective in the treatment of VF refractory to standard therapy. Several small studies have reported successful conversion of VF to a stable rhythm with BT after failure of standard electrical and pharmacologic therapy. Recent studies suggest that earlier use of BT may be associated with improved outcome. Finally, as in animal studies, spontaneous defibrillation has been reported. It is important to note that no drug currently used in the treatment of countershock-refractory VF has been proven effective. The use of some of these drugs is based on tradition rather than scientific evidence. The bulk of currently available scientific data indicates that BT is superior to other commonly used antiarrhythmics in the treatment of VF resistant to countershock.(ABSTRACT TRUNCATED AT 250 WORDS)