Patent ID: 8155731
Filing Date: 2012-04-10
Classification: A61B

Abstract:
1. A method for use with an implantable medical device for detecting changes in posture in a patient in which the device is implanted, comprising: sensing an electrical cardiac signal within the patient using the device; obtaining atrial paced depolarization integral (PDI) measurements of the cardiac signal affected by one or more of patient posture, patient activity and cardiac ischemia; determining an atrial PDI baseline level corresponding to a first posture of a patient; detecting for a significant transient variation period in atrial PDI measurements during which the peak-to-peak values of the PDI measurements fluctuate between two to three times the peak-to-peak values of the atrial PDI measurements defining the first posture atrial PDI baseline level; detecting for a transient decay period subsequent to a significant transient variation period during which the transient PDI measurements gradually decay to a subsequent baseline atrial PDI corresponding to a second posture of the patient; detecting, using a microprocessor, a significant change in patient posture when the significant transient variation period is detected, the transient decay period is detected and a difference between the initial atrial PDI baseline and the subsequent atrial PDI baseline exceeds a predetermined threshold indicative of a significant posture change; and detecting, using the microprocessor, patient activity without a significant change in posture when the significant transient variation period is detected and the difference between the initial atrial PDI baseline and the subsequent atrial PDI baseline does not exceed the predetermined threshold.