Abstract 14707: Electrocardiographic Abnormalities Are Common in DCM Patients’ Family Members With Early Manifestations of DCM

Abstract

Introduction: Imaging and 12-lead electrocardiogram (ECG) are recommended to screen individuals at risk of dilated cardiomyopathy (DCM). Few studies have examined the yield of ECG testing in these individuals. We hypothesized that ECG abnormalities are more frequent in DCM patients’ family members with early imaging manifestations of DCM than in those without. Methods: The multisite DCM Precision Medicine Study collected contemporaneous imaging and ECG in 1226 First Degree Relatives (FDRs) of DCM patients aged ≥ 18 years between 06/2016 and 04/2021. Imaging results were used to classify participants into four phenotype groups: left ventricular systolic dysfunction alone (LVSD), left ventricular enlargement alone (LVE), DCM (both LVSD and LVE), or normal (neither LVE nor LVSD). ECG status was defined as normal, borderline, or abnormal. Analysis of the probability of a borderline or abnormal ECG result was performed using a generalized linear mixed model accounting for clinical site heterogeneity and intrafamilial correlation. Results: Both imaging and ECG findings were normal in 57% of FDRs. ECG findings were abnormal or borderline in 42% of FDRs with LVSD or LVE and 87% of FDRs with DCM. As shown in Table, FDRs with DCM were more likely than FDRs with no LVE or LVSD to have abnormal or borderline ECGs after adjusting for race, ethnicity, age, sex, and family ascertainment site (OR: 13.17; 95% CI: 5.18 - 33.50). African American FDRs had higher adjusted odds of abnormal or borderline ECG findings than White FDRs (OR: 1.59; 95% CI: 1.15 - 2.20). FDRs in the 4th quartile by age had higher adjusted odds of abnormal or borderline ECG findings than FDRs in the 1st quartile (OR: 4.36; 95% CI: 3.01 - 6.33). Conclusions: An abnormal or borderline ECG was substantially more likely in at-risk FDRs who, by imaging, had DCM. This study supports the use of ECG testing in the screening of FDRs for DCM.