Objective to investigate the left ventricular (LV) systolic function by speckle tracking echocardiography before and after percutaneous intramyocardial septal radiofrequency ablation for hypertrophic obstructive cardiomyopathy (HOCM).

Percutaneous intramyocardial septal radiofrequency ablation (named Liwen Procedure) is a safe and effective treatment approach for HOCM and results in sustained improvement in exercise capacity and persistent in reducing left ventricle outflow tract (LVOT) gradient. However, the systolic function of the myocardial after Liwen procedure in HOCM patients is not well exploration and research. Strain evaluation using speckle tracking echocardiography is an excellent tool for assessing regional and global LV functions.

In this study, the investigators aimed to characterize regional and global strain using speckle tracking echocardiography to assess LV radial, circumferential and longitudinal systolic myocardial function in patients with HOCM before and after Liwen procedure.

Inclusion Criteria:

1. Patients with symptoms that limit daily activities (New York Heart Association functional class >II, exercise-induced syncope) despite adequate medical treatment or when medical treatment is not tolerated
2. Patients with a peak LVOT gradient≥50 mm Hg

Exclusion Criteria:

1. Those with a peak instantaneous Doppler LVOT gradient of <50 mm Hg
2. Those with an indication for septal reduction therapy and other lesions requiring surgical intervention (e.g., mitral valve repair/replacement and papillary muscle intervention)
3. Those with end-stage heart failure；and those the echocardialology image quality is not clear enough for strain analysis.