PubMed 24590965

Referenced in Channelpedia wiki pages of: none

Automatically associated channels: HCN3 , HCN4

Title: Ivabradine protects against ventricular arrhythmias in acute myocardial infarction in the rat.

Authors: Urszula Mackiewicz, Joseph Y Gerges, Sandy Chu, Monika Duda, Halina Dobrzynski, Bohdan Lewartowski, Michał Mączewski

Journal, date & volume: J. Cell. Physiol., 2014 Jun , 229, 813-23

PubMed link:

Ventricular arrhythmias are an important cause of mortality in the acute myocardial infarction (MI). To elucidate effect of ivabradine, pure heart rate (HR) reducing drug, on ventricular arrhythmias within 24 h after non-reperfused MI in the rat. ECG was recorded for 24 h after MI in untreated and ivabradine treated rats and episodes of ventricular tachycardia/fibrillation (VT/VF) were identified. Forty-five minutes and twenty-four hours after MI epicardial monophasic action potentials (MAPs) were recorded, cardiomyocyte Ca(2+) handling was assessed and expression and function of ion channels were studied. Ivabradine reduced average HR by 17%. Combined VT/VF incidence and arrhythmic mortality were higher in MI versus MI + Ivabradine rats. MI resulted in (1) increase of Ca(2+) sensitivity of ryanodine receptors 24 h after MI; (2) increase of HCN4 expression in the left ventricle (LV) and funny current (IF) in LV cardiomyocytes 24 h after MI, and (3) dispersion of MAP duration both 45 min and 24 h after MI. Ivabradine partially prevented all these three potential proarrhythmic effects of MI. Ivabradine is antiarrhythmic in the acute MI in the rat. Potential mechanisms include prevention of: diastolic Ca(2+)-leak from sarcoplasmic reticulum, upregulation of IF current in LV and dispersion of cardiac repolarization. Ivabradine could be an attractive antiarrhythmic agent in the setting of acute MI.