Clinical profiles of four large pedigrees with familial dilated cardiomyopathy - Preliminary recommendations for clinical practice

OBJECTIVES This study aimed to characterize the clinical profile of familia l dilated cardiomyopathy (FDC) in the families of four index patients initi ally diagnosed with idiopathic dilated cardiomyopathy (IDC) and to provide clinical practice recommendations for physicians dealing with these disease s. BACKGROUND Recent evidence indicates that approximately one-half of patient s diagnosed with IDC will have FDC, a genetically transmissible disease, bu t the clinical profile of families screened for FDC in the U.S, has not bee n well documented. Additionally, recent ethical guidelines suggest increase d responsibilities in caring for patients with newly found genetic cardiova scular disease. METHODS After identification of four families with FDC, we undertook clinic al screening including medical history, physical examination, electocardiog ram and echocardiogram. Diagnostic criteria for FDC-affected status of asym ptomatic family members was based on left ventricular enlargement (LVE). Su bjects with confounding cardiovascular diagnoses or body mass indices >35 w ere excluded. RESULTS We identified 798 living members from the four FDC pedigrees, and s creened 216 adults and 129 children (age <16 years). Twenty percent of fami ly members were found to be affected with FDC; 82.8% of those affected were asymptomatic. All four pedigrees demonstrated autosomal dominant patterns of inheritance. The average left ventricular end-diastolic dimension was 61 .4 mm for affected and 48.4 mm for unaffected subjects, with an average age of 38.3 years (+/-14.6 years) for affected and 32.1 years for unaffected s ubjects. The age of onset for FDC varied considerably between and within fa milies. Presenting symptoms when present were decompensated heart failure o r sudden death. CONCLUSIONS We propose that with a new diagnosis of IDC, a thorough family history for FDC should be obtained, followed by echocardiographic-based scr eening of first-degree relatives for LVE, assuming their voluntary particip ation. If a diagnosis of FDC is established, we suggest further screening o f first-degree relatives, and all subjects with FDC undergo medical treatme nt following established guidelines. Counseling of family members should em phasize the heritable nature of the disease, the age-dependent penetrance a nd the unpredictable clinical course. (J Am Cell Cardiol 1999;34:837-47) (C ) 1999 by the American College of Cardiology.