Dauricine suppressed CsCl-induced early afterdepolarizations and triggered arrhythmias in rabbit heart in vivo.

Aim: To study the effect of dauricine on CsCl-induced early afterdepolarizations (EAD) and ventricular arrhythmias in rabbits.

Methods: Monophasic action potentials (MAP) of the left ventricle of the rabbit heart in situ were recorded with MAP recording technique. CsCl 1-2 mmol.kg-1 i.v. was used to induce EAD and ventricular arrhythmias.

Results: CsCl resulted in decrease of MAP amplitude (MAPA, P < 0.05) and prolongation of MAP duration at 90% repolarization (MAPD90, P < 0.01), QRS, and R-R duration (P < 0.05) compared with those before CsCl in the dauricine and control group. CsCl injection induced EAD that appeared within about 30 s and disappeared 5-15 min thereafter. EAD always preceded ventricular arrhythmias including ventricular premature beats and paroxysmal ventricular tachycardia. The EAD amplitude (EADA) in the dauricine group (26% +/- 9% of MAPA) was smaller than that in the control group (52% +/- 5% of MAPA, P < 0.05) and the incidence of arrhythmias in dauricine group (28%) was lower than that in control group (80%, P < 0.05).

Conclusion: Dauricine exerted an antagonistic effect on EAD and suppressed triggered ventricular arrhythmias by decreasing EADA.