An implantable system includes a first leadless pacemaker (LP1) implanted in or on a first chamber of a heart and a second leadless pacemaker (LP2) implanted in or on a second chamber of the heart. The LP1 is configured to time delivery of one or more pacing pulses delivered to the first chamber of the heart based on timing of cardiac activity associated with the second chamber of the heart detected by the LP1 itself. The LP1 is also configured to transmit implant-to-implant (i2i) messages to the LP2. The LP2 is configured to time delivery of one or more pacing pulses delivered to the second chamber of the heart based on timing of cardiac activity associated with the second chamber of the heart as determined based on one or more i2i messages received by the LP2 from the LP1.

An implantable system includes a first leadless pacemaker (LP1) implanted in or on a first chamber of a heart and a second leadless pacemaker (LP2) implanted in or on a second chamber of the heart. The LP1 is configured to time delivery of one or more pacing pulses delivered to the first chamber of the heart based on timing of cardiac activity associated with the second chamber of the heart detected by the LP1 itself. The LP1 is also configured to transmit implant-to-implant (i2i) messages to the LP2. The LP2 is configured to time delivery of one or more pacing pulses delivered to the second chamber of the heart based on timing of cardiac activity associated with the second chamber of the heart as determined based on one or more i2i messages received by the LP2 from the LP1.

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.

An implantable medical system includes at least four electrodes forming a dipole emitter and a dipole receiver which is distinct from the dipole emitter. The system is configured to recover physiological mechanical information by way of the two dipoles, by analyzing a received and processed electrical signal, wherein the amplitude has been modulated in accordance with the electrical properties of the propagation medium between the dipole emitter and the dipole receiver. Thus, a parameter which is representative of a pre-ejection period may be extracted from the attenuation of the voltage between the dipole emitter and the dipole receiver by taking an electrocardiogram or an electrogram into account.

A medical device system and method estimate a time from a first voltage of a power source of a medical device to a second voltage of the power source. The medical device includes a sensor coupled to the power source for generating a physiological signal. The medical device system determines a current drain from the power source required for generating the physiological signal and/or processing the physiological signal for detecting events from the physiological signal. A processor of the medical device system is configured to estimate the time from the first voltage of the power source until the second voltage based on at least the determined current drain.

Arterial diastolic pressure of a patient can be estimated using ventricular pressure information of a heart of the patient and heart sound information of the heart of the patient, such as a timing of at least one of a first heart sound (S1) or a second heat sound (S2), in certain examples, adjusted by a respective correction factor.

In some examples, a medical device system includes an electrode. The medical device system may include impedance measurement circuitry coupled to the electrode, the impedance measurement circuitry may be configured to generate an impedance signal indicating impedance proximate to the electrode. The medical device system may include processing circuitry that may be configured to identify a first component of the impedance signal. The first component of the impedance signal may be correlated to a cardiac event. The processing circuitry may be configured to determine that the cardiac event occurred based on the identification of the first component of the impedance signal.

The present invention relates to a system of multiple implantable medical devices for an impedance measurement comprising a first implantable medical device, at least a second implantable medical device distinct from the first implantable medical device and; an analysis module comprising at least one amplifier and one envelope detector, one of the first implantable medical device or the second implantable medical device being a subcutaneous implantable cardioverter defibrillator or a subcutaneous loop recorder, and the other of the first implantable medical device or the second implantable medical device being an implantable endocardial device.

Systems, methods, and devices for delivering stimulating energy with a lead having a directional defibrillation electrode are disclosed. The lead includes a directional defibrillation electrode configured for implantation on or near the inner surface of a rib or the inner surface of the innermost intercostal muscle and having an electrically active portion configured to emanate stimulating energy from an exposed portion of the directional defibrillation electrode toward the pericardium and the heart. The lead also has an electrically insulating portion around at least part of the circumference of the lead. The electrically insulating portion is configured to insulate surrounding muscle and/or tissue from the stimulating energy when the lead is implanted in the patient.

Provided is an accurate, fast and long-term stable fused CRAP. The electrode includes a positioning anchor, a silicone catheter, a sensor compartment and a connecting wire. The method monitors physiological information such as blood PPG, blood oxygen saturation, temperature and impedance of blood in the right ventricular cavity, and monitors blood temperature information, which is also a slowly changing metabolic rate, to provide cross-comparison with blood oxygen saturation information, improving monitoring accuracy of blood oxygen saturation. The rapidly changing right ventricular apical impedance information is monitored to improve rapid response ability of CRAP. The LEDs driving current is dynamically adjusted by monitoring the internal temperature of the PPG sensor and the impedance change of the attached biological tissue, which indirectly reflects thickness change of the attached biological tissue, thereby delaying the failure time of the PPG sensor.