Effects of lithium on time to onset of aconitine-induced initial arrhythmia and ventricular tachycardia.

The effects of lithium on the time to onset of aconitine-induced initial arrhythmia and onset of ventricular tachycardia were determined in mice. The mice were pretreated intraperitoneally with 1.73, 3.0, 5.1 and 8.8 mEq lithium chloride/kg/day for 5 days, or 8.8 mEq LiCl/kg/day i.p. for 1, 3, 5, 7 and 10 days. Lithium prolonged the onset-time to ventricular tachycardia, and this effect was both dose and time dependent. Under these conditions, lithium pretreatment had no effect on the time to onset of aconitine-induced initial arrhythmia. The LD50 was 15.3 mEq/kg. The observed prolongation of the onset of ventricular tachycardia can be explained in part by the influence of lithium on myocardial cations and catecholamines, and the pharmacologic effect of lithium on Purkinje fibers.