The Cutaneous Heart Sounds Data Collection During CRT Optimization study is an acute, prospective, non-randomized multi-center feasibility clinical trial. The purpose of this clinical trial is to collect data to assist in the testing and finalization of a hemodynamic sensor-based cardiac resynchronization therapy (CRT) optimization scheme.

Inclusion Criteria:

• Subject must have been implanted with a Medtronic market approved CRT-D device (Concerto®, Concerto® II, Maximo® II, Consulta®, Protecta™, or Protecta™ XT) within two years
• Subject must be 18 years of age or older
• Subject or his/her legally authorized representative has signed and dated the study specific informed consent form ("Consent Form")
• Subject is willing and able to comply with protocol requirements

Exclusion Criteria:

• Subject with atrial tachyarrhythmia or frequent atrial or ventricular ectopy
• Subject is post mitral or aortic valve repair or replacement
• Subject is participating in other research studies that many confound the results of this study
• Subject is pregnant or in fertile age without secure birth control
• Subject has dementia
• Subject is unwilling to comply with protocol requirements
• Subject has a device and lead system with fractured leads
• Subject cannot undergo an echocardiograph procedure, or is contraindicated to undergo such a procedure

Subjects with an implanted Medtronic market approved CRT-D device.