Hypertrophic cardiomyopathy: diagnosis and assessment of symptoms

The diagnosis of hypertrophic cardiomyopathy (HCM) in adults is based on the presence of left ventricular wall thickness greater than 15 mm using any imaging modality on at least one myocardial segment and not explained solely by abnormal cardiac loading conditions; a 13 mm threshold should be applied for familial screening in first-degree relatives. Diagnosis in children, in the elderly, in hypertensive individuals, and in elite athletes may be challenging. Initial evaluation should include a family pedigree, evaluation of signs and symptoms, electrocardiogram, and 48 h Holter electrocardiogram monitoring, exercise testing, imaging, and biochemistry. The presence of an intraventricular left ventricular obstruction, present in two-thirds of the patients at rest, during Valsalva or exercise, should be systematically evaluated using echocardiography. Cardiovascular magnetic resonance imaging with late gadolinium enhancement should always be considered, particularly to assess apical hypertrophy, left ventricular aneurysms, and fibrosis. This systematic approach is recommended to assist in the detection of HCM not caused by mutations in cardiac sarcomere protein genes (up to 10% of patients). Genetic tests should be performed and interpreted after a careful and complete clinical evaluation and genetic counselling. HCM is characterized by symptoms of dyspnoea, fatigue, chest pain, palpitations, and syncope, which are highly variable. Functional limitation may be difficult to evaluate and often necessitates cardiopulmonary exercise testing.