Distinct comorbidity and functional profiles in obstructive versus non-obstructive hypertrophic cardiomyopathy in the prospective TORCH registry

Background Hypertrophic cardiomyopathy (HCM) encompasses a heterogeneous spectrum ranging from non-obstructive (nHCM) to obstructive (oHCM) disease. While left ventricular outflow tract obstruction guides therapeutic decisions, large-scale comparisons of clinical profiles between these subtypes remain limited. We characterize demographic, comorbidity, functional, and echocardiographic differences between nHCM and oHCM within the prospective, multicentre Translational Registry for Cardiomyopathies (TORCH). Methods We analyzed baseline data from 1,320 HCM patients (558 nHCM, 762 oHCM) enrolled in the TORCH and TORCH-Plus registries. Obstruction status was classified using echocardiographic LVOT gradient assessment. Subtypes were compared for demographics, cardiovascular risk factors, NYHA functional class, echocardiographic parameters, and cardiac biomarkers. Results The overall HCM cohort had a mean age of 55.6±14.4 years with 59.6% male patients. oHCM patients were significantly older (58.0±13.4 vs. 52.3±15.0 years, p<0.001) and had a higher BMI (28.5±5.3 vs. 27.6±5.4 kg/m², p=0.003). Notably, oHCM was associated with a significantly higher burden of cardiovascular risk factors, including hypertension (59.7% vs. 50.7%, p=0.001), diabetes (12.2% vs. 6.6%, p=0.001), dyslipidemia (45.7% vs. 31.4%, p<0.001), sleep apnea (10.1% vs. 5.9%, p=0.032), and coronary artery disease (22.0% vs. 13.3%, p<0.001). In contrast, nHCM was associated with a higher rate of atrial fibrillation (27.8% vs. 20.2%, p=0.002). oHCM patients showed worse functional status with more NYHA class II–III symptoms (58.4% vs. 79.0%, p<0.001) and had higher LVEF (59.3±8.2% vs. 54.6±10.8%, p<0.001). Maximum wall thickness (19.0±4.4 vs. 18.5±5.0 mm, p=0.053), diastolic dysfunction (Grade≥1: 62.7% vs. 49.4%, p=0.094), cardiac biomarkers (NT-proBNP, hs-Troponin) and prevalence of depression (11.3% vs. 9.9%, p=0.459) did not differ significantly between subtypes. Conclusion In the TORCH registry, oHCM and nHCM present with distinct clinical profiles. oHCM is associated with older age, higher cardiovascular risk factor burden, and worse functional class, while nHCM shows a higher prevalence of atrial fibrillation. Notably, markers of myocardial hypertrophy, diastolic impairment, and psychological burden appear comparable across the spectrum. These distinct phenotypic profiles underscore the necessity for comorbidity-adjusted, tailored management strategies that integrate systemic risk factor control with emerging targeted therapies.Key findings.