A battery-powered, hermetically-sealed pulse generator, intended to be implanted beneath the skin of the chest in a surgically-created pocket, and used with pacing leads placed in the right ventricle, in a coronary vein over the left ventricle, and often in the right atrium (triple chamber) to stimulate the heart to beat at a faster rate when it senses bradycardia and provides cardiac resynchronization therapy (CRT) through biventricular electrical stimulation to synchronize right and left ventricular contractions to treat symptoms of heart failure (e.g., easy fatigue) and serious heart-rhythm problems [CRT pacemaker (CRT-P)]; it is not intended for defibrillation therapy.