Figure 6. The [Ca²⁺]_SR termination level of Ca²⁺ sparks is decreased in heart failure myocytes.

A, cytosolic Ca²⁺ sparks and intra-SR Ca²⁺ blinks from a normal myocyte (left image and F/F₀ profile) and heart failure myocyte (right image and F/F₀ profile). Resting fluorescence in heart failure myocytes was normalized to normal myocytes using the value shown in Fig. 5F. B, summary data showing the decreased Ca²⁺ blink [Ca²⁺]_SR termination level of 53.0 ± 1.9% (n= 11) in heart failure myocytes compared with 60.1 ± 0.9% (n= 82) of control myocytes. *P < 0.05 versus control.