REPLACE: Implantable Cardiac Pulse Generator Replacement Registry

Inclusion Criteria: * Is able to give informed consent * Is identified for generator replacement without system modification or generator replacement including planned system modification, regardless of generator manufacturer * Is clinically stable to tolerate the surgical procedure * Age 18 years or greater * Is geographically stable and able to return to the investigational site for follow-up care through the six-month visit Exclusion Criteria: * Inability or unwillingness to give informed consent * Current system infection requiring generator explantation or lead extraction * Generator replacement requiring planned lead extraction * Participating in another cardiovascular investigational drug or device registry * A life expectancy of less than six months * Expected to receive a heart transplant within 6 months * All vulnerable subjects as defined by the FDA Office of Human Research Protection or the local IRB providing oversight