Oxidative stress and ventricular arrhythmias in rabbits with myocardial hypertrophy or heart failure

Objective To discuss the changes of oxidative stress in rabbits with myocardial hypertrophy or heart failure(HF) and explore the relations between oxidative stress and ventricular arrhythmias.Methods Forty Japanese white rabbits were randomly divided into four groups(n=10 each): the Sham 1 group(Sham 1),the Sham 2 group(Sham 2),the left ventricular hypertrophy(LVH) group and the heart failure(HF) group.In LVH group and HF group,the abdominal aorta was partial constricted.In Sham 1 group and Sham 2 group,the abdominal was only exposed without constriction.Rabbits in Sham 1 and LVH group were fed for 8 weeks,and those in Sham 2 and HF group were fed for 20 weeks.Left ventricular end diastolic diameter(LVEDd),left ventricular ejection fraction(LVEF) and interventricular septal thickness(IVST) were measured by echocardiogram.Plasma levels of N-Terminal Pro B-Type Natriuretic Peptide(NT-proBNP),superoxide dismutase(SOD) and malondialdehyde(MAD) were measured and the wedge preparations from the rabbit hearts were perfused with Tyrode′s solution containing isoprenaline(2 μmol/L),and the incidences of trigger actions,ventricular tachycardias(VT) and ventricular fibrillation(VF) were recorded.Results IVST,the serum MDA was increased and the serum SOD was decreased in the LVH group compared with the Sham 1 group.The incidences of trigger actions,VT and VF were significant higher in the LVH group than those in Sham 1 group(P0.05). IVST,LVEDd,the serum MDA and NT-proBNP was increased,the serum SOD and LVEF was decreased,and the incidences of trigger actions,VT and VF were significant higher in the HF group than those in Sham 2 group(P0.05).There were significant differences in MDA,NT-proBNP,SOD,LVEF and LVEDd between the LVH group and HF group(P0.05).The incidences of trigger actions,VT and VF were significant higher in the HF group than those in LVH group.Conclusions The incidences of VT and VF are higher in HF than those in LVH group under stress,which might be closely related with oxidative stress.