An intracardiac ventricular pacemaker includes a pulse generator for delivering ventricular pacing pulses, an impedance sensing circuit, and a control circuit in communication with the pulse generator and the impedance sensing circuit. The pacemaker is configured to produce an intraventricular impedance signal, detect an atrial systolic event using the intraventricular impedance signal, set an atrioventricular pacing interval in response to detecting the atrial systolic event, and deliver a ventricular pacing pulse in response to the atrioventricular pacing interval expiring.

Techniques for switching an implantable medical device (IMD) from a first mode to a second mode in relation to signals obtained from internal sensors are described. The internal sensors may include a temperature sensor and a biosensor. In some examples, processing circuitry of the IMD may make a first preliminary determination that the IMD is implanted based on a first signal from the temperature sensor. In response to the first preliminary determination being that the IMD is implanted, the processing circuitry may make a second preliminary determination that the IMD is implanted based on a second signal from the biosensor. The processing circuitry may switch the IMD from a first mode to a second mode based on both the first preliminary determination and the second preliminary determination being that the IMD is implanted.

Systems and methods for monitoring and treating patients with heart failure (HF) are discussed. The system may sense cardiac signals, and receives information about patient physiological or functional conditions. A stimulation parameter table that includes recommended values of atrioventricular delay (AVD) or other timing parameters maybe created at a multitude of patient physiological or functional conditions. The system may periodically reassess patient physiological or functional conditions. A therapy programmer circuit may dynamically switch between left ventricular-only pacing and biventricular pacing, or switch between single site pacing and multisite pacing based on the patient condition. The therapy programmer circuit may adjust AVD and other timing parameters using the cardiac signal input and the stored stimulation parameter table. A HF therapy may be delivered according to the determined stimulation site, stimulation mode, and the stimulation timing.

Devices, systems and methods provide forms of asymptomatic diaphragmatic stimulation (ADS) therapy that affect pressures within the intrathoracic cavity, including: 1) dual-pulse ADS therapy, during which a first ADS pulse is delivered during a diastolic phase of a cardiac cycle and a second ADS pulse is delivered during a systolic phase, 2) paired-pulse ADS therapy, during which a first ADS pulse is delivered, closely followed by a second ADS pulse, with the second ADS pulse functioning to extend or enhance a phase of a transient, partial contraction of the diaphragm, and 3) multiple-pulse ADS therapy, during which a stream of ADS pulses is delivered, wherein the time between pulses is based on heart rate. Devices, systems and methods also monitor electromyography (EMG) activity of the diaphragm relative to baseline activity to assess the health of a diaphragm subject to ADS therapy and to adjust ADS therapy parameters or sensing parameters.

An implantable medical device for stimulating a human/animal heart, comprising a housing, a processor, a memory unit, a stimulation unit configured to stimulate the His bundle, and a detection unit configured to detect an electrical signal at the His bundle. The device performs: a) stimulating the His bundle with a stimulation pulse delivered by the stimulation unit; b) measuring an electric signal at the His bundle with the detection unit upon termination of a first period of time starting upon delivering of the stimulation pulse, wherein the first period of time is from 35 ms to 500 ms; c) measuring an impedance of the same heart with the detection unit upon termination of a second period of time starting upon delivering of the stimulation pulse, wherein the second period of time is equal to or longer than the first period of time and is from 50 ms to 500 ms.

Systems and methods for monitoring and treating patients with heart failure (HF) are discussed. The system may sense cardiac signals, and receives information about patient physiological or functional conditions. A stimulation parameter table that includes recommended values of atrioventricular delay (AVD) or other timing parameters may be created at a multitude of patient physiological or functional conditions. The system may periodically reassess patient physiological or functional conditions. A therapy programmer circuit may dynamically switch between left ventricular-only pacing and biventricular pacing, or switch between single site pacing and multisite pacing based on the patient condition. The therapy programmer circuit may adjust AVD and other timing parameters using the cardiac signal input and the stored stimulation parameter table. A HF therapy may be delivered according to the determined stimulation site, stimulation mode, and the stimulation timing.

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.

Systems and methods for controlling blood pressure via electrical stimulation of the heart are disclosed. Embodiments may include at least two different stimulation patterns, each configured to reduce blood pressure to a different degree, and may alternate between stimulation patterns based on the need of a patient, for example, alternating between day and night or between periods of strenuous and light activity. Some embodiments may take advantage of a slow baroreflex response that occurs after treatment is stopped, suspending treatment for extended periods, and then resuming treatment before blood pressure levels reach pretreatment values. Embodiments may control blood pressure by controlling atrial pressure and atrial stretch.

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.

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.