Low cardiac output casues a faster heart rate, triggers the kidneys to produce more volume and
the additional volume
stresses the heart as well and
heart failure ensues.
Treatment is to reduce fluids, dilate vessels, slow heart rate, sometimes meds to strengthen contractility, etc. The treatment can/will provide relief to the heart's workload and in time the heart will/can reverse the LV enlargement.
Currently, my heart is normal size and functionality with the exception of MVR.