Aim:The present work was designed to investigate the relationship betweenhemodynamic parameters and the susceptibility of ventricular arrhythmia toaconitine in conscious Lyon hypertensive rats(LH).Methods:Male LH and Lyonlow blood pressure rats(LL)were used.After the determination of baroreflexsensitivity(BRS),ventricular arrhythmia was induced by aconitine infusion inconscious rats.Blood pressure(BP)was recorded during the period of infusion.Results:Compared with the LL rats,the LH rats possessed significantly higherBP,blood pressure variability and lower BRS.The threshold of aconitine requiredfor ventricular fibrillation and cardiac arrest in the LH rats were significantly lowerthan those in the LL rats.It was found that all the hemodynamic parametersstudied were not correlated with the threshold of aconitine required for arrhythmia,with the exception of BRS,which was positively related to the threshold ofaconitine required for ventricular premature beat.Conclusion:The LH rats pos-sessed greater susceptibility to aconitine-induced ventricular arrhythmias whencompared to the LL rats.This greater susceptibility could not be attributed to anyone of the hemodynamic parameters alone studied in the LH rats.It is proposedthat various hypertension-associated abnormalities,including the abnormalhemodynamics,may co-contribute to this vulnerability to ventricular arrhythmias. Aim: The present work was designed to investigate the relationship between hemodynamic parameters and the susceptibility of ventricular arrhythmia toaconitine in conscious Lyon hypertensive rats(LH).Methods:Male LH and Lyonlow blood pressure rats(LL)we used.After the determination of baroreflexsensitivity( BRS), ventricular arrhythmia was induced by aconitine infusion inconscious rats.Blood pressure(BP)was deflated during the period of infusion.Results:Compared with the LL rats, the LH rats possessed significantly higherBP, blood pressure variability and lower BRS.The threshold Of aconitine requiredfor ventricular fibrillation and cardiac arrest in the LH rats were significantly lowerthan those in the LL rats.It was found that all the hemodynamic parametersstudied were not correlated with the threshold of aconitine required for arrhythmia, with the exception of BRS,which was positively Related to the threshold ofaconitine required for ventricular premature beat.Conclusion:The LH rats pos-se Ssed greater susceptibility to aconitine-induced ventricular arrhythmias whencompared to the LL rats.This greater susceptibility could not be attributed to anyone of hemodynamic parameters alone studied in the LH rats.It is known that several hypertension-associated abnormalities,including the abnormalhemodynamics,may co -contribute to this vulnerability to ventricular arrhythmias.