Abstract

Background Sudden cardiac death (SCD) is a tragic event and may be due to inherited cardiac conditions (ICC). Identification of ICCs in surviving family members can prevent further deaths. We present some of the challenges faced in family screening after sudden cardiac death over 13 years. Methods The Somerset sudden cardiac death pathway commenced in 2010. Patients <65 years with 1) unexplained SCD or 2) SCD due to a possible ICC were referred by the coroner to the Somerset SCD pathway. In cases where the cause of death was an ICC, SCD, or sudden arrhythmic death syndrome (SADS), first degree relatives were invited for screening. This included consultation with a cardiologist, 12-lead electrocardiogram (ECG), exercise ECG, 24-hour ECG, and a transthoracic echocardiogram (TTE) ± cardiac magnetic resonance imaging. If these were all normal, selected patients were offered an ajmaline challenge. Results 80 Cases (41 ± 13 years, 65% male) were referred between October 2010 and November 2023, of which 8 were subsequently excluded. Logistics of screening In 27/72 (38%) of cases families declined any screening. 14/72 (19%) probands and 50/183 (27%) of first-degree relatives lived outside of our catchment area. 411 investigations were performed with an ICC diagnosis made in 14 (3.4%) (table 1.) On average, 3.3 relatives per family were screened. Defibrillator implants 3 patients have had an implantable cardioverter defibrillator (ICD). 1 patient received an inappropriate therapy. There have been no appropriate therapies. The indications for implant were; ARVC (2, both asymptomatic) and a Brugada patient who had palpitations with presyncope. The Brugada patients was offered a loop recorder but opted for an ICD and had a right ventricular lead perforation. Genetics 2/13 probands had molecular autopsy with pathogenic variants and 1 with phenotypic features of Loeys-Dietz syndrome (LDS) had a TGFBR1 Variant of Uncertain Significance (VUS). In one family, a pathogenic DSG variant (ARVC) segregated with an asymptomatic relative who was phenotype negative but later died of SCD despite surveillance. Another relative in the same family had a KNCE2 Long QT VUS and received an ICD due to mild left ventricular impairment and a possible epsilon wave but has not received any therapies in 9 years and one generator change. Mild relative phenotypes and uncertainty In two SADS families, 4 family members were ajmaline positive. 8/40 relatives declined the ajmaline challenge. ICC diagnosis was definite in 7 and possible in 3. One relative had possible Long QT and one possible ARVC. Conclusion A significant proportion of families do not engage with family screening or are out of area. Family members often have a less severe phenotype which can make clear diagnoses challenging. The threshold for ICD implant may be lower when families have been devastated by sudden death, but this is not without risk. Long term follow up is required to assess the effectiveness of screening. Conflict of Interest No conflict of interest to declare