Abstract: Methods and devices for determining optimal Atrial to Ventricular (AV) pacing intervals and Ventricular to Ventricular (VV) delay intervals in order to optimize cardiac output. Impedance, preferably sub-threshold impedance, is measured across the heart at selected cardiac cycle times as a measure of chamber expansion or contraction. One embodiment measures impedance over a long AV interval to obtain the minimum impedance, indicative of maximum ventricular expansion, in order to set the AV interval. Another embodiment measures impedance change over a cycle and varies the AV pace interval in a binary search to converge on the AV interval causing maximum impedance change indicative of maximum ventricular output. Another method varies the right ventricle to left ventricle (VV) interval to converge on an impedance maximum indicative of minimum cardiac volume at end systole. Another embodiment varies the VV interval to maximize impedance change.

Abstract: The present invention provides a method and apparatus for detecting and monitoring obstructive sleep apnea. The apparatus includes an intracardiac impedance sensor to measure intracardiac impedance, a movement sensor to measure an amount of movement of a patient, and a controller operatively coupled to said intracardiac impedance sensor and said movement sensor, said controller adapted to receive at least one of an intracardiac impedance and the amount of movement of the patient and detect obstructive sleep apnea based upon said intracardiac impedance and said movement.

Abstract: An apparatus and method for treating sleep apnea includes a control unit in electrical communication with a lead. The control unit is capable of outputting a sleep apnea interruption pulse to stimulate at least one of a phrenic nerve and a diaphragm. Specifically, an implanted medical device (IMD) such as an ICD or a pacemaker paces the heart and a mode switch algorithm changes the pacing output to stimulate at least one of a phrenic nerve and diaphragm when sleep apnea is detected by the control unit. The method includes determining if the patient is experiencing sleep apnea and outputting a sleep apnea interruption pulse to the at least one of a phrenic nerve and a diaphragm. The control unit may be incorporated with the IMD. In another embodiment, the control unit may be in wireless communication with the IMD and positioned outside a patient's body.

Abstract: Enzymes are immobilized on activated carbon supports at high load levels and with high stability by reacting an activated carbon support with a carbodiimide or an isoxazolium salt to form active organic radicals on the surface of the activated carbon support and thereafter treating the carbon support with an enzyme solution to immobilize the enzyme on the carbon support. The immobilization of enzymes on activated carbon provides immobilized enzymes which are easily handled and which are stabilized against denaturation by hydrogen peroxide.

Abstract: Enzymes are immobilized on activated carbon supports at high load levels and with high stability by a procedure whereby a carbon support is first activated with a water-soluble carbodiimide derivative which forms a highly reactive intermediate with carboxyl and other active organic radicals on the surface of the carbon support; thereafter the complex of the carbon and carbodiimide is treated with an enzyme solution whereby the enzyme displaces the carbodiimide and forms a carbon-enzyme complex wherein the enzyme is immobilized and yet the carbon retains its surface activity. Preferred immobilizing agents are quaternary ammonium forms of aminocarbodiimides or hydrochloric acid salts of water-soluble carbodiimides. The immobilization of the enzymes on activated carbon provides materials which are easily handled and which are stabilized against denaturation by hydrogen peroxide.