Recent advances in the therapy of hypertrophic obstructive cardiomyopathy

Hypertrophic obstructive cardiomyocpathy (HOCM) is phenotypically heterogeneous autosomal dominant disease with variant penetrance. Its pathophysiology primarily involves asymmetric ventricular hypertrophy, anterior motion of the systolic mitral valve, and left ventricular outflow tract (LVOT) obstruction, manifested with angina pectoris, fatigue, dyspnea, syncope, heart failure and even sudden cardiac death. Over 50% of the large patient population is drug-refractory, although traditional medications such as β-blockers, non-dihydropyridine calcium antagonists and disopyramide are selectively effective in reducing LVOT obstruction. Thus, these patients should be referred for effective septal reduction therapy, such as surgical septal myectomy or alcohol septal ablation (ASA), which is the main invasive treatment for LVOT obstruction. Recently, mavacamten and aficamten, two novel cardiac myosin inhibitors, have been proven remarkably effective in HOCM patients with LVOT gradient ≥ 30 mmHg, and even ≥ 50 mmHg, who are in New York Heart Association functional class II to III, as demonstrated by several phase 2 to 3 trials. Furthermore, percutaneous intramyocardial septal radiofrequency ablation (PIMSRA), pioneered by Liu Liwen and her colleagues, is a promising procedure because of its minimal invasiveness and comparable outcomes in decreasing LVOT obstruction compared to surgical myectomy or ASA.