Final answer:
Option a) Systolic anterior motion (SAM) of the mitral valve causes LVOT obstruction in Hypertrophic Cardiomyopathy (HCM).
Step-by-step explanation:
a) Systolic anterior motion (SAM) of the mitral valve causes LVOT obstruction in Hypertrophic Cardiomyopathy (HCM).
In HCM, the hypertrophied ventricular septum creates a narrow left ventricular outflow tract (LVOT). During systole, the hypertrophied septum moves towards the mitral valve leaflets, causing them to be pushed anteriorly and into the LVOT. This can obstruct the flow of blood from the left ventricle into the aorta. This phenomenon is known as systolic anterior motion (SAM) of the mitral valve.
Other factors such as a dilated aorta, enlarged left atrium, or right ventricular hypertrophy do not directly cause LVOT obstruction in HCM.