Treatment in hypertrophic cardiomyopathy (HCM) targets the dynamic outflow obstruction that narrows the outflow tract during systole and causes symptoms. Two further problems need their own management: atrial fibrillation with its stroke risk, and the late stage when the ventricle fails. Whether a patient also needs an implantable cardioverter defibrillator is decided by arrhythmic risk rather than by the gradient.
When there is no obstruction
Without obstruction, management is often surveillance, with beta-blockers used to reduce risk though the evidence is not entirely uniform.
Medicines for obstruction
A resting gradient of 30 mmHg is already clinically significant, but the threshold for treating the outflow tract is higher: guidance considers it in symptomatic patients whose peak gradient reaches 50 mmHg or more. Beta-blockers are first line. Verapamil or diltiazem can be used second line, with cautious titration from a small dose, and disopyramide is added in some patients. These medicines lower heart rate and contractility and thereby shrink the dynamic gradient — acting on haemodynamics, not on the diseased protein.
Myosin inhibitors are newer and act directly on the sarcomere’s myosin, modifying actin–myosin interaction; they can reduce hypertrophy and substantially lower the outflow gradient, with very good outcomes reported in studies, as daily lifelong therapy. Mavacamten, a cardiac myosin inhibitor, is considered for patients who remain symptomatic despite beta-blocker therapy.
Septal reduction
Septal reduction is the next step when severe symptoms or unexplained recurrent syncope persist despite medical therapy. Surgical myectomy removes part of the septum through open surgery, while alcohol septal ablation infarcts the segment percutaneously through its septal perforator. Either procedure should be performed by an experienced multidisciplinary team.
Atrial fibrillation
Atrial fibrillation is common in HCM and is a major source of stroke. A rhythm-control strategy is preferred, especially before the left atrium remodels and dilates. Oral anticoagulation is indicated for every patient with HCM and atrial fibrillation unless contraindicated, regardless of the CHA2DS2-VASc score, the usual estimate of stroke risk in atrial fibrillation.
Advanced disease
When the ventricle eventually dilates and systolic function falls — the burned-out stage — management follows heart failure pathways, and heart transplantation is considered in patients who meet eligibility criteria.
Thick walls are not always HCM, though: infiltration by amyloid produces a similar picture from a different cause and is treated on different principles.