Diastolic Spontaneous Calcium Release From the Sarcoplasmic Reticulum Increases Beat-to-Beat Variability of Repolarization in Canine Ventricular Myocytes After β-Adrenergic Stimulation

Abstract

SCR contributes to increased BVR by interspersed prolongation of AP duration, which is exacerbated during I(Ks) blockade. Attenuation of Ca(2+)-induced Ca(2+) release by SCR underlies AP prolongation via increased I(CaL.) These data provide novel insights into arrhythmogenic mechanisms during β-adrenergic stimulation besides triggered activity and illustrate the importance of I(Ks) function in preventing excessive BVR.