TABLE 1.

Shortening during continuous electrical stimulation of adult ventricular myocytes

	Percentage of cell shortening
Min of pacing	Bath > 5 nL (n = 8)	Bath = 100 pL (n = 5)
0	100	100
15	83 ± 12	79 ± 19
20	74 ± 6	73 ± 9
30	69 ± 11	39 ± 16
40	68 ± 13	30 ± 4
50	68 ± 25	13
60	61 ± 27	–

Cells were paced at an average field strength of 30 V/cm and the sarcomere length was continually recorded. The change in sarcomere spacing over time was related to the sarcomere length at rest (100%). Note the drop in cell shortening after 30 min of continuous stimulation in the limited extracellular space of 100 pL volume.