An example system includes memory configured to store a plurality of lead impedances (LeadZs) and processing circuitry communicatively coupled to the memory. The processing circuitry is configured to determine a first sensed LeadZ, and determine a second sensed LeadZ. The processing circuitry is configured to determine a first difference between the first sensed LeadZ and the second sensed LeadZ, and determine a parameter based at least in part on the first difference. The first sensed LeadZ and the second sensed LeadZ are sensed during a same first cardiac cycle or adjacent cardiac cycles of a heart that is receiving pacing.

This document discusses, among other things, systems and methods to generate a first pacing waveform during a first pacing period and a second pacing waveform during a second pacing period, to alternate first and second pacing periods to provide pacing-based hypertension therapy to a heart of a patient to reduce patient blood pressure, to receive information indicative of patient metabolic demand, and to determine an adjusted pacing-based hypertension therapy parameter using the received information indicative of patient metabolic demand, wherein the first pacing waveform has a first atrioventricular (AV) delay and the second pacing waveform has a second AV delay longer than the first AV delay.

Various aspects of the present disclosure are directed toward apparatuses, systems, and methods for supporting components of an implantable medical device. The apparatuses, systems, and methods may include a first electrode and a second electrode and a scaffold assembly configured to support the first electrode and the second electrode.

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.

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.

Methods and devices herein are provided for managing atrial (A) pacing in connection with premature atrial contracts (PAC). The methods and devices obtain an atrial pace-on-PAC (APAC) interval and cardiac activity (CA) signals. The methods and devices are configured to: i) during a first cardiac beat; following a ventricular paced (VP) or ventricular sensed (VS) event, activate a timer for a post ventricular-atrial refractory period (PVARP) interval; and determine whether a first atrial refractory (AR) event occurs during the PVARP interval; ii) during a second cardiac beat; in response to the detecting that the first AR event occurred, initiate an APAC interval; during the APAC interval for the second cardiac beat, determine whether a second AR event occurs; and update a count of APAC events when the second AR event occurs; and iii) repeat i) and ii) for multiple cardiac beats, to track the count of APAC events.

Systems and methods for multi-site cardiac stimulation are disclosed. The system includes an electrostimulation circuit to deliver electrostimulation to one or more candidate sites of at least one heart chamber. The system may sense a physiological signal including during electrostimulation of the heart, use the physiological signal to determine a first stimulation vector for electrostimulation at a first left ventricular (LV) site and a second stimulation vector for electrostimulation at a different second LV site, and determine a therapy mode including a first chronological order and a first timing offset between stimulations delivered according to the first and second stimulation vectors. The electrostimulation circuit may deliver electrostimulation to the heart in accordance with the first and second stimulation vectors and the therapy mode.

A medical electrical lead and methods of implanting medical electrical leads in lumens. Leads in accordance with the invention employ preformed biases to stabilize the lead within a lumen or lumen and to provide feedback to lead implanters.

A medical device senses cardiac electrical signals including T-waves attendant to ventricular myocardial repolarizations and detects a T-wave template condition associated with non-pathological changes in T-wave morphology. The device generates a T-wave template from T-waves sensed by the sensing circuit during the T-wave template condition. After generating the T-wave template, the device acquires a T-wave signal from the cardiac electrical signal and compares the acquired T-wave signal to the T-wave template. The device detects a pathological event in response to the acquired T-wave signal not matching the T-wave template.

An extra-cardiovascular medical device is configured to select a capacitor configuration from a capacitor array and deliver a low voltage, pacing pulse by discharging the selected capacitor configuration across an extra-cardiovascular pacing electrode vector. In some examples, the medical device is configured to determine the capacitor configuration based on a measured impedance of the extra-cardiovascular pacing electrode vector.