Vascular Endothelial Function and Cardiac Resynchronization Response in Patients With Heart Failure

During standard of care device implantation procedure, a small piece of fat tissue will be removed from the device pocket inside the chest

Non-invasive testing for blood vessel function. Specially designed finger probes placed on the middle finger of each hand. Pulsatile volume changes of the distal digit inducing pressure alterations in the finger cuff will be sensed by pressure transducers and recorded. Endothelial function will be measured via a reactive hyperemia (RH)-PAT index (RHI)