Ravi, Sandhya

Abstract Introduction Hypertrophic cardiomyopathy (HCM) is an autosomal dominant disorder with a pathogenic mutation identified in approximately 50% of cases. The MYH7 and MYBPC3 genes account for over half of these cases, while dozens of other genes can be pathogenic(1). Genetic test results are not independently used to determine which people with HCM benefit from implanted cardiac defibrillators (ICDs)(2, 3). Little is known about the additive role of genetic testing results to existing indications for ICD insertion. Purpose This study aims to examine the interaction between genetic testing results and existing ICD indications and imaging results on defibrillator discharge rates in HCM. Methods Patients who underwent an ICD for HCM, who underwent a cardiac magnetic resonance (CMR) study and who underwent genetic testing were included across 3 sites. The outcome was the incidence rate of appropriate ICD discharges, calculated using cox regression controlling for current age and primary vs secondary prevention. Interaction analysis between genetic risk factors and existing ICD indications, and with CMR quantification of LGE and septal thickness, was performed, and stratum specific estimates calculated using linear computation. Results 177 patients were included in the study, of whom 70 (39.55%) had a pathogenic mutation, 5 (2.82%) had a variant likely pathogenic (VLP), 44 (24.86%) had a variant of undetermined significance (VUS) and 58 (39.55%) had no identifiable mutation. The event rate was 3.32 {2.28 to 4.84) per 100 person years. There was no association between genetic variables and ICD discharge rate. There was an 80% reduction in ICD discharge rate in people who underwent ICD insertion exclusively for family history of sudden cardiac death or for syncope who had no pathogenic or likely pathogenic mutation, however this change was not statistically significant (table 2). Conclusion There is no strong association between genetic characteristics and ICD discharge rates among people with hypertrophic cardiomyopathy with an existing ICD indication. There is a nonsignificant trend towards fewer ICD discharges among people who underwent ICD insertion for family history alone or for a history of syncope and did not have a pathologic variant.Table 1 Table 2

Abstract Background Congenital Heart Disease (CHD) is associated with development of atrial fibrillation (AF) at an early age. With increased survival of this cohort into adulthood, the prevalence of concurrent CHD and AF is expected to increase over the next several decades. Little is known about the utility of clinical risk factors or prediction models in determining bleeding or stroke rates in adults with CHD and AF. Purpose This study aims to measure the performance of the CHADSVASC and HASBLED scores in a cohort of people with CHD. The association between traditional stroke and bleeding risk factors, as well as CHD-specific factors, will be quantified. Methods Patients age 18 or older attending one of three centers in the USA were included in this study if they had a history of AF on ECG, holter monitor or device interrogation, in addition to a diagnosis of Tetralogy of Fallot (TOF), Double Outlet Right Ventricle (DORV), or Pulmonary Atresia with Intact Ventricular Septum (PA-IVS). Outcomes were major bleeding event, and stroke rate. Analysis was conducted using cox univariable regression controlling for current age. Receiver operator curve and c-statistics were produced for the CHADSVASC and HASBLED scores respectively. Results 326 people were included in this study, of whom 161 (49.5%) had TOF secondary to Pulmonic Stenosis, 126 (38.8%) had TOF secondary to Pulmonary Atresia, 25 (7.7%) had DORV, and 155 (47.7%) had PA-IVS. 227 people used warfarin (79.4%), 28 (9.8%) used apixaban, 9 (3.1%) used Rivaroxaban, 3 (1%) used Edoxaban, and 5 (1.7%) used Enoxaparin for a period of at least 30 days during the study. 13 (4.5%) people didn’t receive anticoagulation during the study. 26 people had a stroke (8.8%) while 85 people (28.6%) had a major bleeding event. Only the CHADSVASC score was significantly associated with stroke rates (HR 2.103, 95% CI 1.555 to 2.844, p<0.001). Clinical variables, such as subtype of CHD, prior conduit placement or unifocalization were not associated with stroke or major bleeding events. C-statistic for the CHADSVASC score in predicting stroke events was 0.755 (Figure 1). C-statistic for the HASBLED score in predicting major bleeding was 0.442 (Figure 2). Conclusions Among people with CHD and AF, the CHADSVASC score can robustly predict stroke events. Other clinical variables are less valuable in predicting either bleeding or strokes. The HASBLED score likely doesn’t have a role in predicting major bleeding episodes in this cohort.