Left atrial function in hypertrophic cardiomyopathy

Hypertrophic cardiomyopathy (HCM) is a primary cardiomyopathy due to mutation of the genes that code for the sarcomeric proteins of the cardiac muscle cell resulting in an often asymmetric (predominantly septal) left ventricular (LV) hypertrophy that is unconsciously accompanied by left ventricular ejection obstruction. All valvular systemic arterial or systemic diseases that can lead to increased left ventricular mass are excluded from the scope of HCM. HCM is familial in most cases (90%) but sporadic forms exist (10%). The penetrance of the mutation and the expression of hypertrophy is highly variable and age dependent. Its incidence is estimated to be between 0.02 and 0.2% in the general population. The prevalence is estimated at 1/500 in the adult population making this disease the leading hereditary heart disease. This prevalence is underestimated due to the large number of asymptomatic subjects. Cardiac ultrasound is the test of choice for the diagnosis of HCM.