A 45-year-old woman presents with progressive dyspnoea and syncope. Echo shows asymmetric septal hypertrophy (29 mm), systolic anterior motion (SAM) of the mitral valve, and LVOT gradient of 72 mmHg at rest. She is already on metoprolol 200 mg/day with persistent symptoms. According to ACC/AHA 2020 HCM guidelines, the next pharmacological agent approved for LVOT obstruction reduction is:
- A Disopyramide
- B Verapamil
- C Mavacamten (cardiac myosin inhibitor) ✓
- D Spironolactone
Explanation
Mavacamten (brand: Camzyos) is a first-in-class cardiac myosin inhibitor approved by FDA in 2022 for symptomatic obstructive HCM (oHCM). The EXPLORER-HCM trial demonstrated significant reductions in LVOT gradient, symptom burden, and NT-proBNP with mavacamten added to background therapy. It acts by reducing myosin-actin cross-bridge formation, directly addressing the hypercontractility of HCM. Disopyramide (a class Ia antiarrhythmic with negative inotropic properties) is a traditional add-on but lacks FDA approval specifically for oHCM. Verapamil is used in non-obstructive HCM. Spironolactone does not reduce obstruction.
Reference: Harrison's Principles of Internal Medicine, 21st ed.
High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP
Written and medically reviewed by the StethoPrep medical team.