Patent ID: 7389143

Claim:
An implantable medical device, comprising: a controller; one or more sensing/pacing channels, wherein the controller is programmed to control the delivery of pacing pulses in accordance with an atrial-triggered mode such that a ventricular pace is delivered upon expiration of an escape interval designated as the AV delay interval; a minute ventilation sensor interfaced to the controller; an activity level sensor interfaced to the controller for measuring a parameter related to a patient's level of physical activity; wherein the controller is programmed to construct a historical record of activity level versus minute ventilation, referred to as a minute ventilation response profile; wherein the controller is further programmed to monitor a patient's cardiopulmonary functional status by computing a minute ventilation response slope from the minute ventilation response profile, defined as the ratio of an incremental change in minute ventilation to an incremental change in measured activity level, and compare the minute ventilation response slope to a specified limit value; and, wherein the controller is further programmed to decrease the AV delay interval upon detecting that the patient's minute ventilation response slope has worsened to a specified extent.