Atotal artificial heart (tah) is an electrically powered pump that circulates blood into the pulmonary artery and the aorta, thus replacing the functions of both the right and left ventricles. what makes it different from an lvad?

TAH can take over the functions of the two lower heart chambers, while LVAD can take over the left chamber only

Explanation:

LVAD is a ventricular assist device used to help the circulation in the body of people who have problems with the left heart chamber. This device assumes the functions of only this camera, helping the patient to overcome possible problems that the malfunction of this camera may cause.  On the other hand, an artificial heart is an implantable device that replaces the two lower chambers of the heart, called ventricles.

the last statement is correct i.e.

when your heart is not pumping enough blood around your body because your heart is severely failing, you may need an artificial heart. an artificial heart is a mechanical device, about the size of an orange, that is connected to your heart or implanted in your chest to or replace a failing heart.