Abstract
According to the last WHO/ISFC classification of cardiomyopathies,HCM is defined as'hypertrophy of the left/ right ventricle,which is usually asymmetric and involves the interventricular septum'.This hypertrophy may affect any region of the myocardium,however,most aften it is the ventricular septum,either lone or together with the anterior or posterior free wall.If the hypertrophy involves the basal(subaortic)part of the septum,this bulges into the outflow tract,leading to its narrowing - obstructive HCM.The characteristic histological features of HCM are hypertrophy of the heart muscle, its abnormal architecture(disarray), interstitial fibrosis,and presence of thick-walled small intramyocardial arteries.The value of endomyocardial biopsy for diagnosis of HCM is controversial; on one side,the most characteristic histological feature 'the disarray' is not entirely specific for HCM,on the other side, the samples obtained from the superficial layers of interventricular septum may not involve the disarray