F091 Prevalence of reported cardiac conduction abnormalities in Enroll-HD

<h3>Background</h3> Heart disease is the second most common cause of death in patients with Huntington’s Disease (HD), Stephen et al. reported that up to 43.3% of 590 early HD patients had abnormal electrocardiograms (ECGs). However, the prevalence and rate of progression of different types of cardiac arrhythmias across the entire HD spectrum remains unclear. Understanding how these problems unfold during disease progression has important clinical and research implications. <h3>Aims</h3> To determine the prevalence and rate of progression of different types of cardiac conduction abnormalities across the entire HD spectrum using the largest HD observational dataset, Enroll-HD. <h3>Methods</h3> Using the Enroll-HD periodic dataset (cutoff date 12-08-2020), a population of participants that reported one or more of 35 cardiac conduction abnormalities was analyzed. The prevalence was assessed across reported HD disease stages, using both CAP and TMS scores as markers of disease progression. <h3>Results</h3> Approximately 0.40% of pre-manifest participants and 1.12% of manifest participants reported cardiac conduction abnormalities at the baseline visit. Bradycardia and cardiac arrhythmia were most common in the manifest group at approximately 1.5 and 3 times the frequency of controls, respectively. <h3>Conclusion</h3> Compared to the literature, cardiac conduction abnormalities were substantially underreported in the Enroll-HD dataset, highlighting a potential lack of awareness among patients and caregivers. Given the high prevalence and clinical risk of cardiac conduction abnormalities in this population, observational studies should make a concerted effort to better capture these important diagnoses and consider implementing routine ECGs at all visits.