Obstructive Hypertrophic Cardiomyopathy Management

Pathophysiology and Diagnosis

Obstructive hypertrophic cardiomyopathy (HOCM) is a genetic disorder characterized by thickened heart muscle that creates dynamic left ventricular outflow tract (LVOT) obstruction, leading to symptoms of exertional dyspnea, chest pain, palpitations, and reduced functional capacity, as described by the American College of Cardiology 1
Dynamic LVOT obstruction worsens with exercise or Valsalva maneuver, and is associated with impaired diastolic relaxation and compliance, as well as mitral regurgitation secondary to systolic anterior motion, according to the American College of Cardiology 1

The American College of Cardiology recommends mavacamten as second-line therapy for adults with symptomatic NYHA class II-III obstructive HCM who remain symptomatic despite maximally tolerated first-line therapy with beta-blockers or nondihydropyridine calcium channel blockers, with a Class 1 recommendation 2, 3, 4
First-line treatment consists of beta-blockers (titrated to resting heart rate <60-65 bpm) or nondihydropyridine calcium channel blockers (verapamil or diltiazem up to 480 mg/day), as recommended by the American College of Cardiology 2, 3
Mavacamten improves LVOT gradients, symptoms, and functional capacity in 30-60% of patients with obstructive HCM, with specific improvements including LVOT gradient reduction, functional capacity, symptom relief, and quality of life, according to the American Heart Association 2, 3, 4

Mavacamten must be interrupted if LVEF falls below 50% at any visit, with a risk profile that includes LVEF reduction <50% in 5.7% of patients, as recommended by the American College of Cardiology 2, 3
Pregnancy is an absolute contraindication due to teratogenic effects, with requirements including mandatory negative pregnancy test before initiation in women of childbearing potential and effective contraception until 4 months after the last dose, as recommended by the American College of Cardiology 2, 3, 4