Systems and methods for detecting worsening cardiac conditions such as worsening heart failure events are described. A system may include sensor circuits to sense physiological signals and signal processors to generate from the physiological signals first and second signal metrics. The system may include a risk stratifier circuit to produce a cardiac risk indication. The system may use at least the first signal metric to generate a primary detection indication, and use at least the second signal metric and the risk indication to generate a secondary detection indication. The risk indication may be used to modulate the second signal metric. A detector circuit may detect the worsening cardiac event using the primary and secondary detection indications.

This document discusses, among other things, systems and methods to determine an alert state for each of a plurality of patients using received physiologic information, determine an event rate for the plurality of patients for a specific alert state, and adjust a composite HF risk determination for the plurality of patients using the determined event rate.

A medical tool includes a rotation mechanism that further includes a warning feature. The warning feature provides an indication when the rotation mechanism has achieved a number of rotations.

Synchronized stimulation of cardiac tissue can be implemented by implanting two or more rectifier-based AM receivers into different positions within a subject's heart. Each receiver is tuned to a different frequency, and generates an output signal that is capable of stimulating cardiac tissue when a signal at the corresponding tuned frequency arrives at the receiver. An AM transmitter can activate any given one of the receivers by transmitting a signal into the subject's body at the proper frequency. A controller controls the transmitter by commanding the transmitter to transmit pulses of AC at different frequencies at different times, so that when those pulses are received by the correspondingly-tuned receivers, each of the receivers will generate respective output signals that stimulate respective parts of the heart at respective times to promote improved cardiac performance.

A method for treatment of cardiac problems includes performing modulation of a cardiac rhythm of a patient by increasing a number of heart beats the patient during time interval with high pleural pressure relative to the number during low (negative) pleural pressure, wherein an amplitude of the modulation of the cardiac rhythm between these segments is determined by severity of a respiratory effort and lung congestion of the patient.

An example of a system includes an implantable medical device (IMD) for implantation in a patient, where the IMD includes a cardiac pace generator, phrenic nerve stimulation (PS) sensor, a memory, and a controller, and where the controller is operably connected to the cardiac pace generator to generate cardiac paces. The controller is configured to provide a trigger for conducting a PS detection procedure and perform the PS detection procedure in response to the trigger. In performing the PS detection procedure the controller is configured to receive a signal from the sensor, detect PS using the signal from the sensor, and record the PS detection in storage within the IMD.

Systems and methods are described herein for selection of a cardiac cycle, or heartbeat, from a plurality of cardiac cycles monitored over time. The cardiac cycle may be selected using various metrics including a single-cycle metric and a cycle-series metric. Further, the selected cardiac cycle may be used for further cardiac analysis (for example, to generate electrical activation times).

The invention provides methods related to improving heart function.

Systems and methods for treating congestive heart failure with high frequency stimulation are disclosed. A representative method for treating a patient includes applying an electrical signal having a frequency of from about 1 kHz to about 100 kHz to the patient via a treatment system that includes a signal delivery element in electrical communication with the patient's vagus nerve at a portion of the vagus nerve located at or proximate to the anterior interventricular junction of the patient's heart. The method can further include automatically detecting at least one physiological parameter of the patient, automatically determining at least one of an ejection fraction of the patient's heart and a correlate of the ejection fraction based on the detected parameter, and automatically adjusting the applied signal based on the determined ejection fraction.

Systems and methods for managing heart failure are described. The system receives physiological information including a first HS signal corresponding to paced ventricular contractions and a second HS signal corresponding to intrinsic ventricular contractions. The system detects worsening heart failure (WHF) using the received physiological information. A signal analyzer circuit can generate a paced HS metric from the first HS signal and a sensed HS metric from the second HS signal, and determine a concordance indicator between the paced and the sensed HS metrics. In response to the detected WHF, the system can use the concordance indicator to generate a therapy adjustment indicator for adjusting electrostimulation therapy, or a worsening cardiac contractility indicator indicating the detected WHF is attributed to degrading myocardial contractility.