Why don't you ask your doctor about some of the newer ACE inhibitors like AltAce or Zestril.
They are proven effective against cardiomyopathy, may be easier to tolerate, and may be effective in lower doses.
I am personally a believer in ALTACE after taking it for three months.
Your doctor increased the ACE inhibitor dose because of the low ejection fraction. The increased does will hopefully help strenghten your heart muscle and improve the ejection fraction. The diastolic dysfunction was probably there previously, but not commented upon.
Doc. I got the dosage wrong on the question about the captopril. I'm taking 25mg 3 times a day and was increased to 50mg 3 times a day.
James