Polymorphic ventricular tachycardia and other complex arrhythmias in organophosphate insecticide poisoning.

Organophosphate insecticide intoxication produces endogenous acetylcholine poisoning which may precipitate complex ventricular arrhythmias, a relatively unrecognized and potentially lethal aspect of this condition. A case is described in which sinus bradycardia, A-V dissociation, idioventricular rhythms, multiform ventricular extrasystoles, and prolongation of the PR, QRS, and QT intervals were observed. Polymorphic ventricular tachycardia--a chaotic ventricular rhythm characterized by extreme variability of QRS morphology and the R-R interval--which previously has not been reported with organophosphate poisoning, was also present in our case. Metabolic and electrolyte derangements, myocardial injury, autonomic dysfunction, and asynchronous repolarization variously may be involved in the genesis of arrhythmias in organophosphate intoxication. Management of these cases should take into account the possible occurrence of conduction abnormalities and arrhythmias, including polymorphic ventricular tachycardia.