Ca2+ transient data obtained from control myocytes and myocytes prepared with the supplements Cr 20, Cr/Ino/Ado, and Ino/Ado. Pacing frequency was increased stepwise from 0.5 up to 5 Hz. At 5 Hz Iso was added. a Diastolic fura ratio, b Peak [Ca2+]i amplitude, c +dRatio/dt, measures the maximum rate of the Ca2+ transient rise, and d −dRatio/dt, measures the maximum rate of the Ca2+ transient decline. Means ± SE of 2–4 independent myocyte preparations per condition, from which 4–6 myocytes per condition were analyzed. *P < 0.01 two-way ANOVA