Background Hypertrophic cardiomyopathy (HCM) is considered a biventricular myopathic process (1), the hallmark of which is diastolic dysfunction. Whilst resting right ventricular (RV) systolic function is reported to be normal in HCM (2), there is a lack of published data regarding RV diastolic function in HCM. Methodology A prospective study was undertaken in a NHS tertiary centre echocardiography department to collect RV diastolic function parameters in patients with HCM and in healthy control subjects when they attended for transthoracic echocardiography (TTE). Inclusion criteria were; confirmed diagnosis of HCM, or normal TTE in a subject with no cardiovascular diagnoses/risk factors. Exclusion criteria were; diagnosis of another condition independently associated with RV diastolic dysfunction [see reference (3)], previous cardiac surgery, previous alcohol septal ablation, congenital abnormality which may affect right heart flow/pressure, or >moderate valvular regurgitation/stenosis. Statistical analyses were performed using SPSS v24 (IBM). P values <0.05 were considered significant. Results There were significant differences in age (51[22] vs 38[18], p<0.0005), gender (male 56% vs 76%, p=0.035), sinus rhythm (100% vs 88%, p=0.012), body mass index (BMI) (24.7±3.2 vs 28.1±4.1, p<0.005) & heart rate (64[15] vs 60 [12], p=0.012) respectively between 50 control & 50 HCM patients. There were no significant differences in blood pressure. As shown in Table 1, RV diastolic function parameters (TV E/A, RV e’ velocity, RV E/e’ & RV isovolumic relaxation time) are significantly impaired in HCM compared to controls, with the exception of TV E-deceleration time. After controlling for baseline differences in age/gender/BMI/heart rate/rhythm, RV e’ (p<0.001) and the surrogate of RV filling pressure RV-E/e’ (p=0.007) remained significantly impaired in HCM whilst TV E/A (p=0.287) and RV IVRT (p=0.404) did not. Conclusions Some RV diastolic function parameters are impaired in HCM compared to healthy controls. Echocardiographically-derived RV filling pressures are significantly elevated in HCM, suggesting that the disease has pulmonary haemodynamic consequences.