Methods and systems that use implanted posture sensor to monitor pulmonary edema

A method to monitor pulmonary edema of a patient, comprising:

• (a) detecting, using an implanted posture sensor, when a posture of the patient changes from a first predetermined posture to a second predetermined posture;
• (b) determining, based on an impedance signal, an amount of time it takes the impedance signal to achieve a steady state after the posture of the patient changes from the first predetermined posture to the second predetermined posture,
• where the impedance signal is obtained using implanted electrodes and is indicative of at least one of left atrial pressure or intra-thoracic fluid volume of the patient, and
• where the amount of time it takes the impedance signal to achieve a steady state, after the posture of the patient changes from the first predetermined posture to the second predetermined posture, is indicative of a degree of pulmonary edema;
• and
• (c) monitoring the pulmonary edema of the patient based on the determined amount of time it takes the impedance signal to achieve the steady state after the posture of the patient changes from the first predetermined posture to the second predetermined posture.