<qa>  What is the ejection fraction defined as?The patient population will include children newborn to 18 years of age treated for dilated cardiomyopathy at Childrens Healthcare of Atlanta Egleston Campus. Patients receiving pacemaker therapy and medicinal therapy for DCM will be included. For the purpose of this study, dilated cardiomyopathy is defined as an ejection fraction EF of 35 with left ventricular LV dimensions greater that 95 for age. Only patients with normal heart anatomy and those with repaired congenital defects that have 4 chambers will be evaluated. Heart transplant patients and patients who cannot travel to Childrens Healthcare of Atlanta at Egleston for follow-up are excluded from this study. Two distinct patient groups will be examined: 