CRT is a type of treatment to help the heart beat at a normal rhythm and is for heart failure patients whose left and right heart chambers do not beat in unison. A CRT device, or biventricular pacemaker, has three leads. One lead goes to each of the heart's ventricles. The third goes to the right atrium, in the heart's upper chambers. These leads watch for abnormal heart rhythms and send an electrical signal to correct them and make the heart chambers work together.