The discovery of the f-channel and its role in regulating pacemaker activity lead to the development of new pharmacological agents such as ivabradine, which target these f-channels causing a reduction in heart rate by inhibiting the /f current.
The aim of the present work was designed to evaluate the cardioprotective effect of ivabradine on experimentally- induced myocardial infarction and adrenaline-induced arrhythmia in rats. In addition, the present work studied the effect of ivabradine on isolated rabbit's aortic spiral strip and isolated rabbit's heart.
Acute myocardial infarction in rats was induced by isoperameline (150mg/kg subcutenous injection, once) 24 rats were divided into the following groups: group (1) control normal rats, group (II) myocardial infarction – induced rats with no previous treatment, group (III) myocardial infarction – induced rats pretreated with ivabradine (10mg/kg/day) for one week and group (IV)) myocardial infarction – induced rats pretreated with carvedilol (1mg/kg/day) for one week. Electrophysiological, biochemical and histopathological parameters were estimated. pretreatment with either ivabradine or carvedilol show significant improvement in all these parameters with insignificant difference between them.
In the current work 20 rats were used to investigate the protective effects of ivabradine (10mg/kg) and carvedilol (1mg/kg) on adrenaline- induced arrhythmia in anaesthetized rats and the results revealed that both drugs had a prophylactive effect.
Also data obtained in the present work pointed out that ivabradine in gradually increasing doses produce no significant effect on the isolated rabbit's aortic strip and basal myocardial contractility of isolated rabbit's heart.
Both ivabradine and carvedilol have cardioprotective effect against acute MI as well as adrenaline- induced arrhythmia with no significant difference between them, also ivabradine has no effect on contractility of the heart. So, the choice of either drug in these disease states depend on which of them has low side effects.
Key words : (myocardial infarction- arrhythmia- ivabradine – carvedilol)
|
