Sensor Optimization of Cardiac Resynchronization Therapy Response

Inclusion Criteria:

- Subject must be undergoing implant of a new or replacement/upgrade Medtronic CRT-P or
CRT-D device for approved indications.

- Subject is implanted or will be implanted with an right ventricular (RV) lead that
supports bipolar pacing and sensing (e.g. a bipolar pace/sense lead or a true bipolar
defibrillation leads)

- Subject (or subject's legally authorized representative) must be willing to give
informed consent

- Subjects must be at least 18 years of age

Exclusion Criteria:

- Subject has congenital heart disease

- Subject has a tachyarrhythmia (atrial and/or ventricular) at the time of enrollment
and a cardioversion will not be attempted prior to the research procedure

- Subject has unstable coronary artery disease

- Subject cannot undergo transvenous catheterization

- Subject has a mechanical tricuspid or aortic valve prosthesis or history of
significant structural tricuspid or aortic valvular disease

- Subject requires dual chamber cardiac pacing or single chamber (ventricular) pacing
at rest for rate control

- Subject has a recent echocardiogram (within prior 6 months) which revealed the
presence of an LV thrombus

- Subject is pregnant

- Subject is enrolled in a concurrent study that may confound the results of this study
without documented pre-approval from Medtronic study manager