Dissociation of Calcium Transients and Force Development following a Change in Stimulation Frequency in Isolated Rabbit Myocardium

Figure 6

Normalized calcium transient amplitude during changes in pacing frequency. (a) Average relative calcium amplitude () during the transition from 1 Hz to 4 Hz. Maximal and minimal calcium transient amplitudes were averaged for 5 seconds prior to the 4 Hz change in frequency, at the 1-, 2-, 3-, 4-, 5-, and 60-second time points following the frequency switch to 4 Hz. represents statistical significance from 5-second prior value and represent statistical significance from 60-second value, . (b) Average relative maximal and minimal calcium transient amplitude recorded at 1 second prior to the 1 Hz frequency change and at 5, 10, 15, 20, and 60 seconds during the 1 Hz stabilization process (). represents a statistical significance from 1 second prior values. A is considered significant.

(a)

(b)