Final answer:
The hump or break seen on the M-mode of the mitral valve between the E and F points is known as the B notch. This helps in assessing the function of the mitral valve during the cardiac cycle.
Step-by-step explanation:
The hump or break occasionally seen on the M-mode of the mitral valve between the E and F points is designated as the B notch. Understanding the movements of the mitral valve is crucial for assessing cardiac function, and the M-mode echocardiogram is a tool used for this purpose. It displays the motion of structures within the heart as a one-dimensional graph that can help diagnose various cardiac conditions. In the context of ventricular diastole, it's important to note that when the pressure in the ventricles falls below the pressure in the pulmonary trunk and aorta during ventricular relaxation, the semilunar valves close, resulting in the characteristic dicrotic notch on blood pressure tracings. This phase of diastole with no change in volume is termed the isovolumic or isovolumetric ventricular relaxation phase, which is distinct from the activity visualized on the mitral valve as the B notch.