Abstract 4148101: Prevalence and Characteristics of Hypertrophic Cardiomyopathy Phenotype in Patients with Cardiac Sarcoidosis

Introduction: Hypertrophic cardiomyopathy (HCM) and cardiac sarcoidosis (CS) are distinct cardiomyopathies that can lead to heart failure and arrhythmias. Both diseases are under-diagnosed in the general population and often misdiagnosed due to overlapping phenotype. Research Question: This study aimed to investigate the co-occurrence of HCM and CS, define the expected prevalence, and outline their co-existent phenotypes. Goals: To define the prevalence and characteristics of coexistent HCM and CS. Methods: We calculated the expected population prevalence of CS and of HCM. We identified consecutive cases of patients with a CS diagnosis at OHSU and included those meeting CS criteria based on the Heart Rhythm Society (HRS) 2014 guidelines. These patients were then screened for HCM phenotype which was determined by the presence of left ventricular wall thickness greater than or equal to 15 mm that is otherwise unexplained, left ventricular outflow tract obstruction (LVOTO), pathogenic or likely pathogenic genetic variant and findings on cardiac magnetic resonance imaging (CMR). The diagnosis of CS and HCM were based on comprehensive detailed evaluation by expert multidisciplinary team with histological confirmation frequently employed. Results: Among the 46 patients meeting HRS criteria, 7 (15%) were identified with concomitant HCM phenotype. Based on published literature, the expected prevalence of HCM is 0.2%-0.4% and assuming independence between CS and HCM, we should have had 1 or no patients with HCM in our cohort. Notably, patients with the HCM-CS phenotype were predominantly male compared to the CS cohort (85.7% vs. 48.7%), had higher left ventricular (LV) ejection fraction (63.9%±3.8% vs 49.7±15.0%), and higher LV wall thickness (18.7±4.7 mm vs 10.7±2.3 mm). Among the HCM-CS patients, LV hypertrophy was asymmetric in 71.4%, and 71.4% had LV outflow tract obstruction. Characteristics of the two populations are shown in Table. Conclusions: Our data suggest a potential overlap between HCM and CS beyond the expected prevalence. Larger and more detailed pathologic studies will elucidate whether CS can have HCM phenotype versus the presence of common pathobiological processes linking the two entities.