An echocardiographic study of left ventricular torsion in patients with latent obstructive hypertrophic cardiomyopathy

Objective To explore the changes of left ventricular torsion function in patients with latent obstructive hypertrophic cardiomyopathy(HCM), and provide quantitative informations for clinical evaluation of cardiac function. Methods A total of 49 consecutive patients with HCM without left ventricular outflow tract obstruction at rest were enrolled.All subjects underwent exercise stress echocardiography. After exercise left ventricular outflow tract pressure gradient(LVOT-PG)≥30 mmHg was positive for exercise stress test (latent obstruction), while LVOT-PG<30 mmHg was negative for exercise stress test (non-obstruction). An ultrasound system obtained two-dimensional ultrasound images of resting and moving peaks. The global longitudinal strain (GLS), global circumferential strain (GCS), global radial strain (GRS) of the left ventricle 16 segments and left ventricular rotation, twist were analysis using off-line EchoPAC software. The differences of the above parameters were compared between the two groups. Results There were no significant differences in GLS, GRS, GCS and Rotation-B between the two groups in resting and peak period of exercise (all P>0.05), GRS in both groups were significantly increased compared with that before exercise (all P 0.05). Conclusions Left ventricular torsion function is significantly changed in rest and after exercise in latent obstructive HCM patients, providing valuable quantitative information for clinical comprehensive evaluation of cardiac function. Key words: Echocardiography, stress; Latent left ventricular outflow tract obstruction; Cardiomyopathy, hypertrophic; Two-dimensional strain; Left ventricular twist