IMPLANTABLE CARDIAC RHYTHM MANAGEMENT DEVICE FOR ASSESSING STATUS OF CHF PATIENTS

摘要

A method and apparatus for providing congestive heart failure therapy status. An electronic device, preferably a cardiac rhythm management device, capable of measuring transthoracic impedance and for sensing a level of physical activity is implanted in a patient. The transthoracic impedance signal is processed to obtain an estimate of the subject's minute ventilation, respiratory rate, tidal volume, inspiratory rate and expiratory rate. From accelerometer measured activity, an estimate is obtained of oxygen uptake, carbon dioxide production and work rate. Ratios of tidal volume to respiratory rate, tidal volume to inspiratory time, tidal volume to expiratory time, heart rate to minute ventilation, respiratory rate to minute ventilation, tidal volume to minute ventilation, minute ventilation to oxygen uptake, minute ventilation to carbon dioxide production, minute ventilation to work rate, heart rate to work rate, oxygen uptake to heart rate and other ratios are meaningful status indicators for assessing the efficacy of particular therapy regimens to CHF patients.