Cardiac Resynchronisation Therapy (CRT) Device A CRT device, also known as a biventricular pacemaker, is surgically implanted in the chest, just beneath the skin below the collar bone. It functions to treat delay in contractions between the heart’s left and right lower chambers or ventricles in heart failure patients. In a normal heart, the ventricles pump at the same time. However, when a person has heart failure, it is common that the right and left ventricles do not pump together. The device generates small electrical impulses to the heart, which makes the left and right ventricles pump together.