2.2.4. Management

For asymptomatic patients, a conservative approach is preferred. No medication is indicated but periodic follow-up to evaluate the disease evolution is fundamental (39). Left ventricular outflow tract (LVOTO) is defined as rest or provocated LV outflow tract gradient >30 mmHg. In patients with HCM, the symptoms of progressive HF (fatigue, dyspnea) or chest pain in 90% of cases are due to LVOTO. These can be treated first with beta-blockers. Alternatively, if beta-blockers are ineffective or not tolerated, disopyramide when available can be used, or calcium-channel blockers (verapamil and diltiazem). Weight loss must be encouraged. Hypovolemia should be avoided and for this reason vasodilators and diuretics are not indicated [43]. If pharmacological therapy is ineffective or LV outflow gradient is >50 mmHg, invasive treatment can be performed. In this case, usually the first choice to treat LVOTO is ventricular septal myectomy (Morrow procedure) [80]. Second choice is represented by septal alcohol ablation [81].

About 10% of patients with HCM and heart failure symptoms have no LVOTO. In these patients, symptoms are probably sustained by diastolic dysfunction and reduced ventricular filling, even though these alterations could be undetectable with echocardiography [82]. In these patients with no obstruction, if LVEF is >50%, to treat the symptoms, the drugs indicated are ß-blockers, verapamil or diltiazem, low dose loop and thiazide diuretics. If LVEF < + 50% ß-blockers, ACE-i, mineralocorticoid receptor antagonist (MRA), low dose loop and thiazide diuretics can be used [38].

Atrial fibrillation is the most common supraventricular arrhythmia in patients with HCM. It can be responsible for symptoms such as palpitations or dyspnea, and it could worsen the symptoms of heart failure. The treatment is comparable to that used in the general population, but it should be emphasized that patients with HCM are less tolerant to high heart rates and they have a greater thromboembolic risk. In this regard, a more aggressive approach to rhythm control is needed and the introduction of prophylactic anticoagulant therapy without delay is preferable [83].

NSVT is a common finding in routine EKG and is a risk factor for SCD but usually no anti-arrhythmic therapy is required. No evidence exists that sustained monomorphic ventricular tachycardia (VT) that is well tolerated has a worse prognosis compared to NSVT. Patients that do not tolerate VT could be eligible for implantable cardioverter defibrillators (ICDs) therapy and treatment with ß-blockers or amiodarone for secondary prevention (38).

Treatment with mavacamten improved exercise capacity, LVOT obstruction, NYHA functional class, and health status in patients with obstructive hypertrophic cardiomyopathy. The results of this pivotal trial highlight the benefits of disease-specific treatment for this condition. Mavacamten is effective for treatment of symptomatic obstructive hypertrophic cardiomyopathy [84].