Abstract: A device is presented for evaluating whether an episode of sleep apnea is occurring in a patient suffering from chronic sleep apnea disorder, for delivery of appropriate therapy. The device includes circuitry adapted to respond to a cardiac signal generated by the heart. Switching circuitry diverts passage of the heart signal through both a high impedance path and a substantially lower impedance path, and a differential amplifier processes the resulting signal pairs to ascertain the difference in magnitude between the two signals of each pair. An analyzer thereof determines changes in the patient's ventilation, from which inordinately reduced patient ventilation is detected to assess possible occurrence of an episode of sleep apnea. If the analyzer denotes change of ventilation between otherwise regular respiratory cycles, an actual episode of sleep apnea is indicated.

Abstract: A device is presented for evaluating whether an episode of sleep apnea is occurring in a patient suffering from chronic sleep apnea disorder, for delivery of appropriate therapy. The device includes circuitry adapted to respond to a cardiac signal generated by the heart. Switching circuitry diverts passage of the heart signal through both a high impedance path and a substantially lower impedance path, and a differential amplifier processes the resulting signal pairs to ascertain the difference in magnitude between the two signals of each pair. An analyzer thereof determines changes in the patient's ventilation, from which inordinately reduced patient ventilation is detected to assess possible occurrence of an episode of sleep apnea. If the analyzer denotes change of ventilation between otherwise regular respiratory cycles, an actual episode of sleep apnea is indicated.

Abstract: An improved method is presented for evaluating the physiological status of a patient diagnosed with congestive heart failure and treating the patient accordingly to alleviate the congestive heart failure. As part of the method, the thoracic or cardiac impedance and ventilation of the particular patient are derived solely from an input consisting of cardiac signals (EKG) generated by electrical energy of the patient's heart as the heart is undergoing its cardiac cycle with a dynamic impedance obtained by subjecting the EKG to alternately high and low input impedances. The derived thoracic impedance and ventilation are used to control the pattern and rate at which stimulating electrical pulses are applied to the patient's vagus nerve by an implanted stimulator, in a manner to deliver therapy to the patient's heart by adjusting the heart rate to a prescribed target rate for alleviating the congestive heart failure.

Abstract: A method is presented for evaluating whether an episode of sleep apnea is occurring in a patient suffering from chronic sleep apnea disorder, for delivery of appropriate therapy. The method, performed by an implantable device, includes sensing the patient's EKG signal and using electrical energy generated by the heart to power subsequent signal processing. This signal is applied as the sole input to a differential signal processing circuit for passage through both a high impedance path and a substantially lower impedance path and amplification of the difference in magnitude between the resulting two signals, to determine changes in the patient's thoracic impedance. Based on such changes, the presence or absence of patient ventilation is detected, to enable an assessment of whether an episode of sleep apnea is occurring. An actual episode of sleep apnea is deemed to have occurred if lack of ventilation exceeds a predetermined interval of time between otherwise regular respiratory cycles.

Abstract: A method and a device are disclosed for evaluating the cardio-circulatory and pulmonary condition of a patient, including determining the patient's thoracic impedance based on information solely derived from the electrical energy generated by the patient's own heart.

Abstract: A method is presented for evaluating whether an episode of sleep apnea is occurring in a patient suffering from chronic sleep apnea disorder, for delivery of appropriate therapy. The method, performed by an implantable device, includes sensing the patient's EKG signal and using electrical energy generated by the heart to power subsequent signal processing. This signal is applied as the sole input to a differential signal processing circuit for passage through both a high impedance path and a substantially lower impedance path and amplification of the difference in magnitude between the resulting two signals, to determine changes in the patient's thoracic impedance. Based on such changes, the presence or absence of patient ventilation is detected, to enable an assessment of whether an episode of sleep apnea is occurring. An actual episode of sleep apnea is deemed to have occurred if lack of ventilation exceeds a predetermined interval of time between otherwise regular respiratory cycles.

Abstract: A method and a device are disclosed for evaluating the cardio-circulatory and pulmonary condition of a patient, including determining the patient's thoracic impedance based on information solely derived from the electrical energy generated by the patient's own heart.

Abstract: An improved method is presented for evaluating the physiological status of a patient diagnosed with congestive heart failure and treating the patient accordingly to alleviate the congestive heart failure. As part of the method, the thoracic or cardiac impedance and ventilation of the particular patient are derived solely from an input consisting of cardiac signals (EKG) generated by electrical energy of the patient's heart as the heart is undergoing its cardiac cycle with a dynamic impedance obtained by subjecting the EKG to alternately high and low input impedances. The derived thoracic impedance and ventilation are used to control the pattern and rate at which stimulating electrical pulses are applied to the patient's vagus nerve by an implanted stimulator, in a manner to deliver therapy to the patient's heart by adjusting the heart rate to a prescribed target rate for alleviating the congestive heart failure.

Abstract: A method and a device are disclosed for evaluating the cardio-circulatory and pulmonary condition of a patient, including determining the patient's thoracic impedance based on information solely derived from the electrical energy generated by the patient's own heart.

Abstract: A method and a device are disclosed for evaluating the cardio-circulatory and pulmonary condition of a patient, including determining the patient's thoracic impedance based on information solely derived from the electrical energy generated by the patient's own heart.