Abstract: Methods and systems to modulate timing intervals for pacing therapy are described. For each cardiac cycle, one or both of an atrioventricular (A-V) timing interval and an atrial (A-A) timing interval are modulated to oppose beat-to-beat ventricular (V-V) timing variability. Pacing therapy is delivered using the modulated timing intervals.

Abstract: This document discusses, among other things, a system including an implantable medical device. The implantable medical device includes a control circuit and a motion sensing device. The motion sensing device is coupled to the control circuit, and the motion sensing device is configured to transmit signals to the control circuit. The control circuit is configured to identify one or more steps of a patient using the motion sensing device signal.

Abstract: An implantable cardiac device is configured and programmed to assess a patient's cardiopulmonary function by evaluating the patient's minute ventilation response. Such evaluation may be performed by computing a minute ventilation response slope, defined as the ratio of an incremental change in minute ventilation to an incremental change in measured activity level. The minute ventilation response slope may then be compared with a normal range to assess the patient's functional status.

Abstract: A cardiac pacing system controls the progression of a cardiac disorder such as heart failure by delivering cardiac pacing to create or augment regional stress in the heart. The cardiac pacing is delivered intermittently, such as on a periodic basis, according to a cardiac stress augmentation pacing sequence that includes alternating pacing and non-pacing periods. One or more physiological signals are monitored for closed-loop control of the cardiac pacing using baseline characteristics of the cardiac disorder, acute cardiac stress created by the cardiac pacing, and/or risk associated with the cardiac pacing.

Abstract: The invention relates to cardiac rhythm management systems, and more particularly, to rate adaptive cardiac pacing systems and methods. In an embodiment, the invention includes a method for providing rate-adaptive cardiac pacing therapy from an implantable medical device, the method including sensing a pulmonary function of a patient; determining a rate of change in the pulmonary function; sensing a cardiac function of the patient; determining a rate of change in the cardiac function; and calculating a target pacing rate based on an existing pacing rate, the rate of change in the pulmonary function, and the rate of change in the cardiac function.

Abstract: Adaptive rate pacing for improving heart rate kinetics in heart failure patients involves determining onset and sustaining of patient activity. The patient's heart rate response to the sustained activity is evaluated during a time window defined between onset of the activity and a steady-state exercise level. If the patient's heart rate response to the sustained activity is determined to be slow, a pacing therapy is delivered at a rate greater than the patient's intrinsic heart rate based on a profile of the patient's heart rate response to varying workloads. If determined not to be slow, the pacing therapy is withheld. Monitoring-only configurations provide for acquisition and organization of physiological data for heart failure patients. These data can be acquired on a per-patient basis and used to assess the HF status of the patient.

Abstract: 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.

Abstract: A method for automatically determining the ventilatory (or “anaerobic”) threshold breakpoint for adaptive rate pacing without the need for directly measuring anaerobic threshold or ventilatory threshold comprises: (a) positioning a first sensing electrode in the heart or superior vena cava of a patient carrying an implanted pacemaker, the first sensing electrode connected to the implanted pacemaker; (b) positioning a second sensing electrode in the thoracic region of the patient and spaced apart from the first sensing electrode; (c) determining the chest wall impedance of the patient between the first sensing electrode and the second sensing electrode; (d) measuring the ventilation (e.g., the minute ventilation) of the subject from the chest wall impedance during submaximal exercise by the patient; and then (e) determining the ventilatory threshold breakpoint of the patient from the measured ventilation.

Abstract: 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 and tidal volume. From accelerometer measured activity, an estimate is obtained of oxygen uptake and carbon dioxide production. Ratios of tidal volume to respiratory rate, tidal volume to inspiratory time, minute ventilation to carbon dioxide production and oxygen uptake to heart rate are meaningftil status indicators for assessing the efficacy of particular therapy regimens to CHF patients.

Abstract: Exertion levels of a patient are measured by monitoring signals from adaptive-rate sensors such as an accelerometer and or a minute ventilation sensor; sensor data is collected for conversion into metabolic equivalent measurements. The data obtained can be used to evaluate patient physical activity levels and can be used to assess the patient's condition and change pacing therapy or other treatments accordingly. An automatic adjustment of the adaptive-rate pacing therapy may be based on the activity levels detected by the metabolic equivalent measurements made by the pacemaker.