Calsequestrin 2 deletion shortens the refractoriness of Ca2+ release and reduces rate-dependent Ca2+-alternans in intact mouse hearts

► Ablation of calsequestrin accelerates restitution of Ca2+ release from SR. ► The ablation of calsequestrin speeds up the rate of change of Ca2+ within the SR. ► The lack of calsequestrin does not affect the restitution Ca2+ influx through the plasma membrane. ► Calsequestrin regulates the appearance of Ca2+ alternans and AP repolarization alternans. ► Calsequestrin ablation modifies TW-alternans.