Phenotypes and clinical outcomes of hypertrophic cardiomyopathy from a large cohort in Turkiye

Abstract Background Hypertrophic cardiomyopathy (HCM) is an inherited myocardial disorder characterized by left ventricular hypertrophy that cannot be fully explained by loading conditions. Over the past three decades, numerous studies have assessed the prevalence of HCM in the general population using echocardiography and cardiac magnetic resonance imaging (CMR), as well as clinical diagnoses derived from electronic health records and billing databases. Purpose This study aimed to assess the distribution, clinical characteristics, and diagnostic approaches in a regional cohort of patients with HCM. Methods We retrospectively analyzed patients diagnosed with HCM at a tertiary cardiomyopathy clinic between October 2021 and November 2024. Patients were classified into obstructive, latent obstructive, non-obstructive, or apical phenotypes based on clinical and imaging findings. Comprehensive demographic, clinical, and imaging data were collected for detailed analysis, providing valuable insights into the phenotypic diversity of HCM. Results The cohort included 701 patients with a median age of 53 years of whom 68% were male. The phenotypic distribution comprised 9.3% apical, 38.1% non-obstructive, 32.5% resting obstructive, and 20.1% latent obstructive HCM. ICD implantation was more common in obstructive phenotypes, particularly in the latent obstructive group. Although LGE was more frequently observed in apical HCM, post-hoc analysis showed no significant difference in prevalence across subgroups. In contrast, LGE extent was significantly greater in the apical group. Genetic testing, performed in 32% of patients, revealed a 44% positivity rate, with MYBPC3 and MYH7 being the most commonly detected mutations. The overall mortality rate was 2.8%, with heart failure identified as the leading cause of death. Conclusion In this large regional cohort of HCM patients, obstructive and non-obstructive phenotypes were predominant, with a notable burden of genetic mutations and a low overall mortality rate primarily driven by heart failure. These findings emphasize the clinical heterogeneity of HCM and highlight the importance of comprehensive diagnostic evaluation.Hypertrophic cardiomyopathy phenotypes Genetic test outcomes