Fig. 4.

Impaired contractility in ENH^−/− hearts. 5-month-old male ENH^−/− (n=8) and WT mice (n=8) were subjected to hemodymic measurements. A and B, ENH^−/− and WT mice had the same heart rates and maximum left ventricular pressure. C, ENH^−/− mice showed lower dP/dt maximum (dP/dt max) when stimulated with 4-8U (U=μg/kg/min) of dobutamine (* p < 0.05). D, ENH^−/− mice had lower dP/dt minimum (dP/dt min) under basal conditions and with various doses of dobutamine (* p < 0.05). E, Tau, a load independent measure of relaxation, was increased in EHN^−/− mice under basal conditions and following various doses of dobutamine ranging from 2-8U (* p < 0.05).