A biometric monitoring device is used to determine a user's heart rate by using a heartbeat waveform sensor and a motion detecting sensor. In some embodiments, the device collects collecting concurrent output data from the heartbeat waveform sensor and output data from the motion detecting sensor, detects a periodic component of the output data from the motion detecting sensor, and uses the periodic component of the output data from the motion detecting sensor to remove a corresponding periodic component from the output data from the heartbeat waveform sensor. From this result, the device may determine and present the user's heart rate.

Wearable heart rate monitor

Systems and methods for monitoring, diagnosing, and/or treating a patient are provided. One or more individual medical procedures may be utilized to monitor, diagnose and/or treat the patient. Two or more of the individual medical procedures or may be used in combination to provide more comprehensive patient monitoring, diagnosis and/or therapy. One or more functions of two or more individual medical procedures may be used in combination to enhance patient monitoring, diagnosis and/or therapy. The medical procedures may be coordinated. Coordinated medical procedures may involve cooperative operation of two or more of the individual processes. Coordinated medical procedures may also involve cooperative operation of one or more functions of two or more of the individual processes.

Patient monitoring, diagnosis, and/or therapy systems and methods

A cardiac rhythm management (CRM) device detects transthoracic impedance, extracts ventilation or other information, and adjusts a delivery rate of the CRM therapy accordingly. A four-phase sequence of alternating direction current pulse stimuli is periodically delivered to a patient's thorax. A transthoracic impedance signal is extracted using a weighted demodulation. Signal processing extracts ventilation information and removes cardiac stroke information using an adaptive lowpass filter. The adaptive filter cutoff frequency is based on the patient's heart rate; a higher cutoff frequency is provided for higher heart rates. Peak/valley detection indicates tidal volume, which is integrated to extract minute ventilation (MV). Short and long term averages are formed and compared to establish a MV indicated rate. Rate adjustment ignores MV information when a noise-measurement exceeds a threshold. An interference avoidance circuit delays delivery of the stimuli when telemetry pulses or other interfering signals are detected.

Rate adaptive cardiac rhythm management device using transthoracic impedance

The present inventions, in one aspect, are directed to portable biometric monitoring device including a housing having a physical size and shape that is adapted to couple to the user's body, at least one band to secure the monitoring device to the user, a physiological sensor, disposed in the housing, to generate data which is representative of a physiological condition of the user data. The physiological sensor may include a light source to generate and output light having at least a first wavelength, and a photodetector to detect scattered light (e.g., from the user). A light pipe is disposed in the housing and optically coupled to the light source directs/transmits light therefrom along a predetermined path to an outer surface of the housing. Processing circuitry calculates a heart rate of the user using data which is representative of the scattered light.

Portable biometric monitoring devices and methods of operating same

The present inventions, in one aspect, are directed to a portable activity monitoring device comprising a housing having a physical size and shape that is adapted to couple to the user's body, a plurality of sensors (for example, motion sensor and altitude sensor) disposed in the housing. The monitoring device may further include processing circuitry, disposed in the housing and electrically coupled to the plurality of sensor, to calculate the activity points corresponding to the physical activity of the user using the sensor data, wherein the activity points correlate to an amount and intensity of the physical activity of the user, and output the data which is representative of the activity points. The monitoring device may also include a display, coupled to the processing circuitry, may output the data which is representative of the activity points to the user.

Portable monitoring devices and methods of operating same

A rate adaptive cardiac rhythm management device in which the pacing rate is adjusted in accordance with changes in the patient's minute ventilation. An adaptive four-pole elliptic digital filter, preferably implemented in software, functions to attenuate any signal components due to cardiac activity and motion from the minute ventilation signal over the range of breathing frequencies encountered in going from a sedentary state to active exercise. The pacemaker incorporates a microprocessor-based controller that is programmed to compute from peak-to-peak excursions of the sensed parameter the instantaneous tidal volume. Likewise, it computes, using a zero-crossing technique, the breathing interval. Knowing the breathing interval and the instantaneous tidal volume, it is possible to compute minute ventilation over a predetermined time interval and it is that factor that is employed in developing the ultimate control signal used to vary the stimulating rate between a lower rate limit and an upper rate limit.

Rate adaptive cardiac rhythm management device control algorithm using trans-thoracic ventilation

An endocardial lead having first and second spaced apart electrodes resides in a patient's heart. The first electrode is a sensing electrode and the second electrode is a carrier signal driving electrode. The lead has a conductor coupling a source of alternating current carrier signals of a predetermined frequency to the second electrode. A third electrode is in electrical contact with body tissues. A cardiac pacer apparatus includes a pacer can which functions as a fourth electrode and has a plastic top wherein the third electrode is located. Said third electrode acts in cooperation with the first electrode to form a pair of sensing electrodes. The sensing electrode pair is further coupled to a sense amplifier for receiving an amplifying modulated electrical signals developed across the sensing electrode pair. A demodulator and filters circuit for demodulating the modulated carrier signal and recovering the modulating signal therefrom is connected to the output of the sense amplifier. The modulating signal is proportional to instantaneous stroke volume of the patient's heart and the demodulator and filters circuit develops a control signal therefrom called a stroke volume signal. The control signal is applied to the pulse generator so as to control the rate of stimulating pulses.

Variable rate cardiac pacer

A cardiac pacemaker signal processing circuit adapted to obtain an evoked ECG signal. The circuit senses the electrical signals of the ring and tip electrodes in the unipolar mode from the bipolar lead after the electrical pacing stimulus has been applied to contract the ventricle of the heart. The residual oppositely polarized potentials at the ring and tip electrode, as well as the sensed evoked ECG signals, are added together to cancel out the opposing residual potentials, but to add the common polarized ECG signal. Thus, a high quality evoked ECG signal is obtained, free of the residual potentials, and subsequently utilized by R-wave detection circuits for sensing the QRS complex. The circuit includes compensating signal processing circuits to provide time domain signal processing weighting functions to match exponential time delay of the tip and ring electrodes, and includes amplitude adjusting compensation as well. Thus, the absolute amplitudes of the opposite polarized residual potentials will be adjusted to be equal, are summed, and canceled or nulled at the appropriate time in the time domain. Both biphasic and tripbasic pace pulse techniques are not required, the pace pulse amplitude can be reduced to extend the battery life of the pacemaker. Further, the post pace re-charging cycle is only interrupted and undertaken-passively to, again, reduce current drain on the battery. Classic R-wave detection circuits are adaptable to the signal processing circuit of the present invention.

Electrode charge-neutral sensing of evoked ECG

A rate adaptive cardiac pacemaker incorporating a switched capacitor filter whose cut-off frequency is varied as a function of heart rate allows respiration-related signals appearing in the intracardiac impedance waveform to be separated from signals relating to systolic events over a frequency range of interest, allowing either or both of the respiration-related signal component or the systolic event component to be used in adjusting the pacing rate.

Rate adaptive cardiac pacer incorporating switched capacitor filter with cutoff frequency determined by heart rate

A variable rate cardiac pacer apparatus is responsive to the physical activity of the patient. A source of alternating current carrier signals of a predetermined frequency is coupled to the pacer housing. At least one sensing electrode is coupled to the carrier signals. The sensing electrode and the pacer housing are structured and arranged to operate as a pair of interface sensing electrodes. A sense amplifier apparatus is coupled to the sensing electrodes for receiving and amplifying modulated electrical signals developed across the sensing electrodes. A demodulator circuit apparatus is structured and arranged to receive the amplified modulated carrier signal which is proportional to the impedance field around the sensing electrode. The frequency of the demodulated signal is proportional to the patient's rate of movement. A signal processing apparatus receives the demodulated signal and provides a processed signal proportional to impedance changes sensed at the interface. A rate control apparatus determines the rate at which the heart stimulating pulse will be generated in response to the processed signal.

John A. Hauck

Papers

Rate adaptive cardiac rhythm management device control algorithm using trans-thoracic ventilation

Variable rate cardiac pacer

Electrode charge-neutral sensing of evoked ECG

Rate adaptive cardiac pacer incorporating switched capacitor filter with cutoff frequency determined by heart rate

Rate responsive pacemaker apparatus having an electrode interface sensor