Fig. 2. Elementary Ca²⁺release events (Ca²⁺sparks) in a ventricular myocyte. The top panel shows confocal images (x,y scans) of a myocyte obtained using a confocal laser scanning microscope. The local regions of increased fluo-3 fluorescence are Ca²⁺sparks. The middle panel shows a Ca²⁺spark recorded using the line-scan (x,t) mode of imaging.