in fig1 with a patient 20 in one form of the present invention the external device 14 is external to the body of patient 20 and in another form of the invention the device 14 may comprise a fully or partially implantable device in both forms of the present invention the device 14 includes a sensor 24 that senses or measures hemodynamic function of the heart of patient 20 more particularly the device 14 generates at least one hemodynamic datum relating to the hemodynamic function and transmits a signal reflecting the hemodynamic datum via a transmitter unit tx unit 22 to programmer 16 the tx unit 22 may comprise circuitry to establish a wireless or hard wired communication link with programmer 16 in addition mutual communication among the device 14 whether disposed outside partially outside or implanted within the patient the programmer 16 and the imd 18 is preferably established intermittently or continuously according to the present invention such mutual communication enhances the process of optimizing the programming of the imd 18 and the resulting hemodynamic function of the patient furthermore such mutual communication enhances the operation of device 14 as more fully described herein the phrase u201c hemodynamic data u201d covers any information that relates to one or more discrete characteristics or metrics of the hemodynamic and or mechanical function of the heart typical hemodynamic data include stroke volume cardiac output and heart rate as well as any of the factors enumerated above in the summary of the invention that vary as a reflect directly or indirect on hemodynamic and or mechanical function of a patient the present invention is intended to encompass all factors that vary as a function of hemodynamic operation.