Dauricine suppressed CsCl-induced early afterdepolarizations and triggeredarrhythmias in rabbit heart in vivo

AIM: To study the effect of dauricine on CsCl-induced early afterdepolariza tions (EAD) and ventricular arrhythmias in rabbits. METHODS: Monophasic act ion potentials (MAP) of the left ventricle of the rabbit heart in situ were recorded with MAP recording technique. CsCl 1-2 mmol . kg(-1) iv was used to induce EAD and ventricular arrhythmias. RESULTS: CsCl resulted in decrea se of MAP amplitude (MAPA, P<0.05) and prolongation of MAP duration at 90 % repolarization (MAPD(90), P <0.01), QRS, and R-R duration (P < 0.05) compa red with those before CsCl in the dauricine and control group. CsCl injecti on induced EAD that appeared within about 30 s and disappeared 5 - 15 min t hereafter. EAD always preceded ventricular arrhythmias including ventricula r 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.