Table 3.

Effect of low-level expression of α-MHC on the time required to reach peak force

	Time Required to Reach Peak Force, ms	Percent Decrease in Time to Peak Force From 0% α-MHC	Fold Decrease in Time to Peak Force From 0% α-MHC
0% α-MHC	76.8		1
10% α-MHC	72.8	5.2	0.95
20% α-MHC	70.0	8.9	0.91
30% α-MHC	67.6	12	0.88

Data were obtained from model predictions of twitch time courses in myocardium with variable ratios of α-MHC and β-MHC. Peak force was determined as the maximal force elicited by a Ca²⁺ transient. The fold decrease in time to peak force from 0% α-MHC was computed as the ratio of the time to peak force from 10%, 20%, and 30% α-MHC to 0% α-MHC. The time to peak force decreased with each incremental addition of α-MHC, with a concomitant increase in the rate of rise of force. The greatest increase in rate was observed when 10% α-MHC was compared with 0% α-MHC. When each incremental addition of α-MHC was compared with the iteration before it (e.g., 20% α-MHC compared with 10% α-MHC), the increase in the rate of rise of force became progressively smaller.