The Effection Of Ivabradine On Ventricular Arrhythmia In Heart Failure Canine

Objectives: To explore the effects of Ivabradine on ventricular arrhythmia in heart failure canine model,and investigate the underlying mechanisms.Methods: Implanted pacing device through chest,heart failure models were successful established after 4 weeks of rapid pacing.Then heart failure canines were divided randomly into drug intervention group(n=6)and heart failure but no drug intervention group group(n=6).In addition,there were 6 beagles as the sham-operation group(n=6).The beagles of drug intervention group were received ivabradine(2mg/kg/d)feeding for 2 weeks.Then all of canines were recivied electrophysiological testing.Results: Compared with the baseline,there were no Statistical difference of heart rate,QTc,QTcd,ERP,dERP,the inducing rate of ventricular arrhythmia and ventricular fibrillation threshold in sham-operation group after 4 weeks and 6 weeks.Campared with baseline,heart rate increased significantly in heart failure of drug intervention group and heart failure of no drug intervention grop in fourth weeks(153.83 ± 7.22 bpm vs 120.83 ± 4.21 bpm,154.83 ± 6.15 bpm vs 116.33 ± 3.67 BPM,P < 0.001),QTc,QTcd,ERP,dERP was significantly prolonged,the incidence of ventricular arrhythmias increased obviously(88.3% vs 16.7%,85% vs 21.7%,P < 0.001),ventricular fibrillation threshold was lower clearely(4.9 ± 0.52 V vs 9.1 ± 0.47 V,4.97 ± 0.66 V vs 9.07 ± 0.52 V,P < 0.001),there were statistically significant difference.Compared with fourth weeks,the heart rate of the canines in heart failure of the drug intervention group in sixth weeks slowed down,QTc,QTcd,ERP,dERP decreased,still longer than 0 weeks,there was statistic difference(P < 0.05).Conclusion: In chronic heart failure canines,Ivabradine reduce heart rate,QT interval and ERP,thereby reduce the incidence of induced ventricular arrhythmia,ventricular fibrillation threshold.Ivabradine has the potential value in the treatment of chronic heart failure and ventricular arrhythmia.