The following is a summary of “Family Screening in Dilated Cardiomyopathy: Prevalence, Incidence, and Potential for Limiting Follow-Up” published in the November 2022 issue of Heart Failure by Vissing et al.

Incomplete penetration and inheritance patterns suggest that less than half of relatives of probands with dilated cardiomyopathy will get the condition. The goal of this research was to examine family members who had cardiac screening to determine the frequency and prevalence of familial dilated cardiomyopathy (FDC) and to identify risk factors for this condition. Families were evaluated and tracked at a regional consortium of clinics for hereditary cardiomyopathies between 2006 and 2020, making this study a retrospective, longitudinal cohort study. 

Overall, 563 female cousins from 211 families participated. A total of 124 close relatives (22% of the total) had FDC at baseline. In 37% of families investigated, the cause was found using genetic sequencing, and 101 (18%) family members were categorized as either unaffected carriers ( n=43) or noncarriers (i.e., not at risk of FDC [n=58]). The base yield for both clinical and genetic analysis was 30%. During the follow-up period (2,313 person-years, median 5.0 years), 45 cases of FDC emerged, bringing the total yield up to 34% (incidence rate: 2.0% per person-year; 95% CI: 1.4%-2.8%). Relatives with abnormal ECG or echocardiogram findings at baseline were more likely to develop FDC than those with normal findings (4.7% vs. 0.4% per person-year; HR: 12.9; P<0.001).

 Baseline screening found that 326 out of 580 (58%) family members were not at high risk for FDC. 1 in 3 baseline family members had a genetic susceptibility to or overt FDC, as determined by screening. In addition, over 50% of relatives received negative genetic and clinical screening results, indicating a low chance of getting FDC during follow-up. Therefore, the baseline screening indicated a sizable fraction in whom follow-up may safely be lowered, allowing for targeted follow-up of family members at risk.