A 42-year-old woman with hypertrophic obstructive cardiomyopathy (HOCM) has resting LVOT gradient 68 mmHg, exertional syncope and NYHA class III symptoms despite maximally tolerated beta-blocker. Septal wall thickness is 22 mm. Which therapy specifically reduces LVOT obstruction by targeting myosin ATPase and was approved in 2022 for HOCM?

• A Disopyramide
• B Mavacamten (cardiac myosin inhibitor) ✓
• C Alcohol septal ablation
• D Surgical myectomy (Morrow procedure)

Explanation

Mavacamten (Camzyos) is a first-in-class cardiac myosin inhibitor that reduces excessive actin-myosin cross-bridge formation, thereby decreasing LVOT obstruction and improving symptoms in obstructive HCM. It was FDA-approved in April 2022 based on the EXPLORER-HCM trial, which demonstrated significant reductions in LVOT gradient, improvement in NYHA class, and peak VO₂. It is indicated for symptomatic obstructive HCM despite conventional therapy (beta-blockers, calcium channel blockers). Disopyramide is a non-approved off-label option. Surgical myectomy or alcohol ablation are invasive options for drug-refractory or severely obstructed patients.

Reference: Harrison's Principles of Internal Medicine, 21st ed.

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Written and medically reviewed by the StethoPrep medical team.