Velocity vector imaging echocardiography and N- terminal pro- brain natriuretic peptide study of people with preclinical hypertrophic cardiomyopathy

Background: To investigate whether familial hypertrophic cardiomyopathy (HCM) gene mutation carriers without overt left ventricular hypertrophy have subclinical changes in left ventricular function.Methods: We studied Eighteen HCM families with pathogenic mutations, 45 patients with overt HCM (gene positive/phenotype positive (G+/P+)), 40 patients without myocardial hypertrophy (gene positive/phenotype negative G+/P-)), and 48 genotype-negative related healthy controls. Conventional echocardiography and velocity vector imaging (VVI) were performed, and blood levels of N- terminal pro- brain natriuretic peptide (NT- pro- BNP) were analyzed.Results: Although the global longitudinal, circumferential and radial strain was similar between the G+/P- group and the control group, the longitudinal strain of basal inferoseptum and basal anteroseptum was lower in G+/P- patients than in controls, while the basal and middle inferolateral longitudinal strains were significantly higher. Compared with the controls, G+/P+ patients had significantly lower global and segmental longitudinal and radial strains. There were no significant differences between the normal control and G+/P+ groups for global and segmental circumferential strains. The middle of the left ventricle (LV) was clockwise in G+/P+ patients (opposite to normal).The rotation angle of the mid LV rotation in the G+/P+ group were significantly higher than those in the G+/P- subjects and controls. The NT-proBNP levels were higher in G+/P+ patients than in G+/P- people and controls.Conclusions: Sarcomere gene mutation carriers without overt left ventricular hypertrophy have subclinical segmental systolic dysfunction. Velocity vector imaging is feasible for differentiating HCM, G+/P- patients from controls.