Abstract: In some examples, a method for controlling delivery of cardiac therapy and cardiac sensing by a medical device system including electrodes for delivering the cardiac therapy may include storing, in a memory of the medical device system, a respective value for each of a plurality of cardiac therapy and/or sensing parameters and, in association with each of a plurality of heart position states, a respective modification of at least one of the cardiac therapy and/or sensing parameters. Such a method also may include determining a current one of the plurality of heart position states of the patient, modifying the at least one cardiac therapy and/or sensing parameter value according to the modification associated with the current heart position state, and controlling the delivery of the cardiac therapy and/or cardiac sensing according to the modified at least one cardiac therapy and/or sensing parameter value.