Asymmetrical hypertrophy of left ventricle: Hypertrophic cardiomyopathy or secondary hypertrophy?

Hypertrophic cardiomyopathy (HCM) is a common genetically transmitted disease, clinically defined by the presence of unexplained left (or right) ventricular hypertrophy. For precise diagnosis of HCM a physician must rule out the secondary causes of left ventricular (LV) hypertrophy, such as aortic stenosis, systemic hypertension or Fabry's disease. We present three cases of asymmetric hypertrophy of LV with subaortic stenosis associated with aortic stenosis in one case and systemic hypertension in two other cases, but the hemodynamic stress caused by these diseases is not sufficient to account for the degree of LV hypertrophy seen in our patients. At the same time, aortic calcinosis and systemic hypertension can mimic the clinical pattern of HCM or can be superimposed on the heart with genetic predisposition to HCM, leading to inadequate hypertrophy of LV and acting as initiating factors that lead to phenotypic expression of genotypic abnormality. The differential diagnosis is very hard and almost impossible in these cases. With this view, only genetic and histological analyses are able to direct a physician to make precise diagnosis without subjective assessment of LV hypertrophy correspondence with aortic stenosis or systemic hypertension. Nevertheless, the management of such conditions does not depend on the type of genetic defect and degree of cardiomyocyte disorientation, but rather on degree of LV outflow tract (LVOT) gradient, LV hypertrophy, aortic stenosis, systemic hypertension and heart failure. For this aim echocardiography is a gold standard diagnostic procedure and is able to distinguish the degrees of parameters mentioned above.