Frequency of Development of Idiopathic DCM Among Relatives of Patients With Idiopathic DCM
One report described transverse and longitudinal clinical and echocardiographic observations of cases of familial DCM but without systematic outcome analyses. Crispell et al. reported clinical profiles of four large pedigrees with familial DCM. They screened 216 adults and 129 children (age <16 years); 20% of relatives were affected and 17% of those affected were asymptomatic. The relatives of all ages were classified as affected if they had an established diagnosis of DCM or were 16 years of age or older with LV enlargement and no other confounding issues. They recommended that first-degree relatives of patients with DCM should undergo electrocardiography and echocardiography screening for early detection and treatment of the disease. However, these studies were performed on a few large families highly selected for familial DCM.
In contrast, Baig et al. reported 225 relatives of an unselected series of patients with DCM and found that, at initial echocardiographic studies, 3% had DCM, 20% had LV enlargement in diastole, 6% had depressed fractional shortening, and 71% had normal echocardiography. At mean follow-up of 39 months, 27% of relatives having initial LV enlargement progressed to DCM. No relatives with normal LV size at initial echocardiography developed DCM at follow-up; however, 2% who were initially assessed as normal had progressed to LV enlargement.
Recently, Michels et al.[4,24] reported a 10-year follow-up study of a large number of relatives who were part of the original study of familial DCM reported in 1992. The frequency of familial disease had increased to 30%. In 674 first-degree relatives of patients with DCM, 591 (88%) were initially unaffected (normal echocardiography or LV size >95th percentile with normal LVEF). Another 50 relatives were affected with DCM, and 33 were considered indeterminate because they had intercurrent disease or were >40 years old and had not undergone catheterization to exclude coronary artery disease. They obtained some form of follow-up through questionnaires and medical record review on 431 relatives, but only 127 (29%) had follow up LVEF measurements. Of these 127 previously unaffected relatives, nine (7%) had developed DCM. In addition, three of the remaining 304 relatives died as a result of DCM. Thus, of the initial group of 591 unaffected relatives, 12 (2.0%) had developed DCM. This may represent a minimal frequency because some of the previously healthy relatives with no follow-up may have developed disease. Furthermore, some relatives who reportedly remained free of disease but did not have follow-up measurements of LVEF may have developed asymptomatic DCM. Some of the relatives who had developed DCM over the 10-year follow-up period did not have LV enlargement at the initial study. It is possible that they passed through this phase undetected; however, the strongest prediction of later development of DCM at follow-up was an enlarged LV in systole with or without enlargement in diastole.
Cardiovasc Rev Rep. 2004;25(5) © 2004 Le Jacq Communications, Inc.
Cite this: Familial Dilated Cardiomyopathy - Medscape - Sep 01, 2004.