A 38-year-old man presents with exertional dyspnoea and presyncope during exercise. Examination reveals a harsh systolic ejection murmur at left lower sternal border that increases with standing and Valsalva manoeuvre and decreases with squatting. LV outflow gradient is 55 mmHg at rest. He is on bisoprolol. What is the current first-line pharmacological agent specifically approved for symptomatic obstructive HCM that targets cardiac myosin?
- A Verapamil
- B Disopyramide
- C Mavacamten ✓
- D Ranolazine
Correct answer: C. Mavacamten
Explanation
Mavacamten is a first-in-class cardiac myosin inhibitor (allosteric inhibitor of myosin ATPase) that reduces dynamic LVOT obstruction in obstructive HCM by reducing excessive myosin cross-bridge formation. The EXPLORER-HCM trial demonstrated significant improvement in LVOT gradient, NYHA class, and exercise capacity. FDA approved in 2022, it is the first disease-specific pharmacotherapy for obstructive HCM. Verapamil and disopyramide are older empirical agents without robust trial data and specific mechanistic targeting. Ranolazine has no approved indication in HCM.
Reference: Harrison's Principles of Internal Medicine, 21st ed.
High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP
Written and medically reviewed by the StethoPrep medical team.