TABLE 2

Tension development, myosin-ATPase activity, and tension cost in human nonfailing and failing myocardium without β-blocker treatment

Parameter
NF (n = 5 Men)
DCM_NBB (n = 5 Men)
Tension
    Maximum (mN/mm2) 21.4 ± 1.9 13.7 ± 1.5 *
    EC50 Ca2+ (μM) 0.71 ± 0.07 0.43 ± 0.04*
Actomyosin-ATPase activity
    Maximum (μM ADP/s) 40.2 ± 2.2 45.4 ± 1.6 *
    EC50 Ca2+ (μM) 0.64 ± 0.04 0.38 ± 0.02*
Tension-dependent ATP consumption
    α [(μM ADP · s-1)/(mN · mm-2)]
1.79 ± 0.03
3.67 ± 0.05*

  • α, slope of the myosin-ATPase/tension relationship; EC50 Ca2+, Ca2+ concentration at which a 50% increase of tension or myosin-ATPase activity was achieved.

  • ↵* p < 0.05 vs. NF.