The goal of this observational study is to learn about the occurrence of various arrhythmias ( tachyarrhythmia and bradyarrhythmia ) during or after Percutaneous Intramyocardial Septal Radiofrequency Ablation. The main questions it aims to answer are:

• To investigate the occurrence of various arrhythmias ( tachyarrhythmia and bradyarrhythmia ) during procedure and its relationship with clinical characteristics and procedural parameters
• To analyze the changes of 12-lead electrocardiogram and 24-hour dynamic electrocardiogram before and after Percutaneous Intramyocardial Septal Radiofrequency Ablation and their relationships with clinical characteristics and procedural parameters

Inclusion Criteria:

1. Subject 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. Subject with a peak LVOT gradient≥50 mm Hg
3. Subject volunteers for the Liwen procedure and received the procedure at the Hypertrophic Cardiomyopathy Center of Xijing Hospital.

Exclusion Criteria:

1. Subject with a peak instantaneous Doppler LVOT gradient of <50 mm Hg
2. Subject with an indication for septal reduction therapy and other lesions requiring surgical intervention (e.g., mitral valve repair/replacement and papillary muscle intervention)
3. Subject has end-stage heart failure

Patients who are diagnosed with obstructive HCM and with drug-refractory symptoms underwent Liwen Procedure in Xijing Hospital from 2016 to 2023.