Genotype-Related Clinical Characteristics and Myocardial Fibrosis and Their Association with Prognosis in Hypertrophic Cardiomyopathy

Background: The spectrum of genetic variants and their clinical significance of Hypertrophic cardiomyopathy (HCM) have been poorly studied in Asian patients. The objectives of this study were to assess the spectrum of genetic variants and genotype–phenotype relationships within a Korean HCM population. Methods: Eighty-nine consecutive unrelated HCM patients were included. All patients underwent genotypic analysis for 23 HCM-associated genes. Clinical parameters including echocardiographic and cardiac magnetic resonance (CMR) parameters were evaluated. A composite of major adverse cardiac and cerebrovascular events was assessed. Results: Genetic variants were detected in 55 of 89 subjects. Pathogenic variants or likely pathogenic variants were identified in 27 of HCM patients in MYBPC3, TNNI3, MYH7, and MYL7. Variants of uncertain significance were identified in 28 patients. There were significant differences in the presence of non-sustained ventricular tachycardia (p = 0.030) and myocardial fibrosis on CMR (p = 0.029) in the detected compared to the not-detected groups. Event-free survival was superior in the not-detected group (p = 0.006). Conclusion: Genetic variants in patients with HCM are relatively common and are associated with adverse clinical events and myocardial fibrosis on CMR. Genotypic analysis may add important information to clinical variables in the assessment of long-term risk for HCM patients.