Patent ID: 7731658

Claim:
An apparatus for monitoring a patient's blood glucose level, the apparatus comprising: (i) an implantable medical device having a controller; (ii) an implantable heart sounds sensor configured to transmit signals to the controller of the implantable medical device; and (iii) wherein the controller is configured to determine if a patient is hypoglycemic or hyperglycemic based on the signals from the heart sounds sensor, wherein the controller is configured to detect the amplitude of an S2 heart sound from the signals from the heart sounds sensor, determine the time interval between an S1 heart sound and the time of the maximum amplitude of the S2 heart sound (S2 max ), determine the time interval between the S1 heart sound and an end of the S2 heart sound (S2 end ), where the controller stores baseline data derived from a signal from the heart sounds sensor and then compares signals later received from the heart sounds sensor to the baseline data to determine if a patient is hypoglycemic or hyperglycemic; and wherein the controller determines that the patient is hypoglycemic if the amplitude of the S2 heart sound deviates by a predetermined threshold from a baseline, and if both the time interval from S1 to S2 max and from S1 to S2 end lengthens relative to the baseline by a predetermined threshold.