Abstract: A medical device system and method for delivering mechanically fused left ventricular cardiac stimulation. A sensor monitors left ventricular acceleration while left ventricular cardiac stimulation is provided at an AV interval. The left ventricular acceleration is used to calculate a mechanical response interval and the mechanical response interval is compared to a desired mechanical response interval. The AV interval is adjusted until the mechanical response interval is equal to the desired mechanical response interval.

Abstract: A method for determining an optimal pacing timing control parameter setting is provided for use in an implantable medical device programmed to deliver a pacing pulse in response to the timing control parameter. The method includes storing a user-selected optimization metric, iteratively adjusting the timing control parameter setting, sensing a first signal that varies in response to left ventricular wall acceleration, measuring the user-selected optimization metric in response to the sensed first signal, and determining an optimal timing control parameter value in response to the measured user-selected optimization metric.

Abstract: An implantable medical device system and associated method are provided for measuring an excitation-physiological response delay. The method includes sensing a first signal responsive to electrical activity in a first cardiac chamber, sensing a second signal responsive to a physiologic response to the electrical activity in the first cardiac chamber; and determining an excitation-physiologic response delay in response to the first signal and the second signal.

Abstract: A method for use in an implantable medical device, comprising: sensing a signal corresponding to ventricular wall acceleration; and determining a metric of atrial function using the ventricular wall acceleration signal. The method includes sensing the ventricular wall acceleration signal during at least during a sensing window corresponding to a ventricular filling phase.