Abstract
OBJECTIVES: Hypertrophic cardiomyopathy (HCM) frequently leads to myocardial ischemia and cardiac dysfunction. Even genotype-positive/phenotype-negative (G(+)/P(-)) individuals, carriers of pathogenic sarcomere gene mutations without left ventricular hypertrophy, remain at risk of progression to clinical HCM. This study aims to evaluate myocardial perfusion and contractile function in familial HCM patients and their first-degree relatives using myocardial contrast echocardiography (MCE) and velocity vector imaging (VVI), in order to identify early myocardial dysfunction and at-risk individuals within families. METHODS: Thirty-five genetically confirmed HCM patients with left ventricular hypertrophy were assigned to a G(+)/P(+) group. A total of 30 first-degree relatives carrying sarcomere mutations but without echocardiographic evidence of left ventricular hypertrophy were assigned to a G(+)/P(-) group. A total of 38 age- and sex-matched gene-negative healthy family members served as controls. All participants underwent MCE and VVI assessments. Myocardial perfusion parameters, including peak intensity (PI), time to peak concentration (TP), and the ratio of declining intensity and declining time (dI/dT), as well as strain parameters including global longitudinal strain (GLS), global radial strain (GRS), and global circumferential strain (GCS) were recorded and analyzed for differences and correlations. RESULTS: Compared to both the G(+)/P(-) and normal control groups, the G(+)/P(+) group had significantly lower PI, dI/dT, GLS, and GRS, along with significantly increased TP (all P<0.05). GLS and GRS were positively correlated with PI (r=0.629 and r=0.613, respectively; both P<0.01) and negatively correlated with TP (r=-0.597 and r=-0.571, respectively; both P<0.01). Compared to the normal control group, the G(+)/P(-) group showed a significant reduction in GLS (P<0.05), but no significant differences in GRS, GCS, PI, TP, or dI/dT (all P>0.05). CONCLUSIONS: Myocardial contractile dysfunction in HCM patients is closely related to impaired perfusion. Even in the absence of wall hypertrophy, sarcomere mutation carriers show early signs of subclinical left ventricular dysfunction. MCE and VVI can quantitatively assess myocardial perfusion and function, offering valuable tools for early detection and risk stratification in HCM patients and their relatives.