A system to measure intracardiac impedance includes implantable electrodes and a medical device. The electrodes sense electrical signals of a heart of a subject. The medical device includes a cardiac signal sensing circuit coupled to the implantable electrodes, an impedance measurement circuit coupled to the same or different implantable electrodes, and a controller circuit coupled to the cardiac signal sensing circuit and the impedance measurement circuit. The cardiac signal sensing circuit provides a sensed cardiac signal. The impedance measurement circuit senses intracardiac impedance between the electrodes to obtain an intracardiac impedance signal. The controller circuit determines cardiac cycles of the subject using the sensed cardiac signal, and detects tachyarrhythmia using cardiac-cycle to cardiac-cycle changes in a plurality of intracardiac impedance parameters obtained from the intracardiac impedance signal.

A controller detects a cyclic cardiac event of the patient based on a signal obtained from one or more electrodes configured for placement on or near a diaphragm, and delivers an electrical stimulation therapy to a diaphragm of the patient through the one or more electrodes. The delivery of electrical stimulation therapy is timed to the detection of the cyclic cardiac event, and the electrical stimulation therapy is defined by stimulation parameters. The controller monitors a pressure associated with the intrathoracic cavity of the patient based on a signal provided by a pressure measurement source configured to provide a signal indicative of a pressure within an intrathoracic cavity, to determine whether an adjustment of one or more of the stimulation parameters is warranted.

Systems, methods, and interfaces are described herein for noninvasively determining an optimal coronary sinus branch to cannulate for a medical electrical lead. One exemplary method involves applying an electrode apparatus having a plurality of electrodes to a torso of a patient. One of a right ventricular (RV) lead is introduced to a right ventricle or a right atrial (RA) lead is introduced to a right atrium. Noninvasively ultrasonic energy is introduced to a target tissue selected from a set of target tissues. In response to delivering ultrasonic energy to the cardiac tissue, a processing unit receives a torso-surface potential signal from each of a plurality of electrodes distributed on a torso of a patient for the target tissue. Signals are sensed from one of the RA lead and the RV lead in response to delivering ultrasonic energy. For at least a subset of the plurality of electrodes, calculating, with the processing unit, a torso-surface activation time based on the signal sensed from the electrode. Determining whether the tissue site or the another tissue site provides optimal cardiac resynchronization.

Systems, methods, and interfaces are described herein for noninvasively determining an optimal coronary sinus branch to cannulate for a medical electrical lead. One exemplary method involves applying an electrode apparatus having a plurality of electrodes to a torso of a patient. One of a right ventricular (RV) lead is introduced to a right ventricle or a right atrial (RA) lead is introduced to a right atrium. Noninvasively ultrasonic energy is introduced to a target tissue selected from a set of target tissues. In response to delivering ultrasonic energy to the cardiac tissue, a processing unit receives a torso-surface potential signal from each of a plurality of electrodes distributed on a torso of a patient for the target tissue. Signals are sensed from one of the RA lead and the RV lead in response to delivering ultrasonic energy. For at least a subset of the plurality of electrodes, calculating, with the processing unit, a torso-surface activation time based on the signal sensed from the electrode. Determining whether the tissue site or the another tissue site provides optimal cardiac resynchronization.

Modular, miniaturized cardiovascular sensors, systems, methods, and wearable devices for the non-obtrusive evaluation, monitoring, and high-fidelity mapping of cardiac mechanical and electromechanical forces and central arterial blood pressure are presented herein. The sensor manufacturing process is also presented. Using accelerometers, the sensors register body-surface (preferably torso-surface) movements and vibrations generated by cardiac forces. The sensors may contain single-use or reusable components, which may be exchanged to fit different body sizes, shapes, and anatomical locations; they may be incorporated into clothing, bands, straps, and other wearable arrangements. The invention presents a practical, noninvasive solution for electromechanical mapping of the heart, which is useful for a wide range of healthcare applications, including the remote monitoring of heart failure status and the guidance of cardiac resynchronization therapy. Exercise and cardiovascular fitness tracking applications are also presented.

Techniques and systems for monitoring cardiac arrhythmias and delivering electrical stimulation therapy using a subcutaneous device (e.g. subcutaneous implantable (SD)) and a leadless pacing device (LPD) are described. In one or more embodiments, a computer-implemented method includes sensing a first electrical signal from a heart of a patient through a SD. The first signal is stored into memory and serves as a baseline rhythm for a patient. Subsequently, a second signal is sensed from the heart through the SD. A cardiac condition can be detected within the sensed second electrical signal through the SD. A determination is made as to whether cardiac resynchronization therapy (CRT) is appropriate to treat the detected cardiac condition. A determination can then be made as to the timing of pacing pulse delivery to cardiac tissue through a leadless pacing device (LPD). The LPD receives communication from the SD requesting the LPD to deliver CRT to the heart. The SD senses and extracts data from a third electrical signal from the heart of the patient to determine whether the pacing by LPD provided efficacious resynchronization or whether the delivery and timing of the LPD pulse should be modified.

Systems and methods are provided for delivering neurostimulation therapies to patients for treating chronic heart failure. A neural fulcrum zone is identified and ongoing neurostimulation therapy is delivered within the neural fulcrum zone. The implanted stimulation device includes a physiological sensor for recording the patient's response to the neurostimulation therapy on an ambulatory basis over extended periods of time.

An example of a system for pacing through multiple electrodes in a ventricle includes a sensing circuit to sense cardiac signal(s), a pacing output circuit to deliver pacing pulses, a heart sound sensor to sense a heart sound signal, and a control circuit to control the delivery of the pacing pulses. The control circuit includes a heart sound detector to detect heart sounds using the heart sound signal, an electrical event detector to detect cardiac electrical events using the cardiac signal(s), a measurement module to measure an optimization parameter using the detected heart sounds, and an optimization module to approximately optimize one or more pacing parameters using the measured optimization parameter. The one or more pacing parameters include an electrode configuration parameter specifying one or more electrodes selected from the multiple electrodes in the ventricle for delivering ventricular pacing pulses to that ventricle.

Systems and methods for detecting an arrhythmic event and storing physiological information associated with the detected arrhythmic event are described. A system may include a first detector to detect an arrhythmic event from a physiological signal sensed from a subject, and generate a confidence indicator indicating a confidence level of the detection of the arrhythmic event. If the confidence indicator indicates a relatively high confidence of arrhythmia detection, the system may provide the detected arrhythmic event to a first process for storing the detected arrhythmic event or generating an alert. If the confidence indicator indicates a relatively low confidence of arrhythmia detection, the system may provide the detected arrhythmic event to at least a second process including confirming or rejecting the detected arrhythmic event.

An apparatus comprises a cardiac signal sensing circuit configured for coupling electrically to a plurality of electrodes and to sense intrinsic cardiac activation at three or more locations within a subject's body using the electrodes; a stimulus circuit configured for coupling to the plurality of electrodes; a signal processing circuit electrically coupled to the cardiac signal sensing circuit and configured to determine a baseline intrinsic activation vector according to the sensed intrinsic cardiac activation; and a control circuit electrically coupled to the cardiac signal sensing circuit and stimulus circuit and configured to: initiate delivery of electrical pacing therapy using initial pacing parameters determined according to the baseline intrinsic activation vector; initiate sensing of a paced activation vector; and adjust one or more pacing therapy parameters according to the paced activation vector.