This disclosure relates to an active implantable medical device of the cardiac resynchronizer type. The device includes a pulse generator to produce pacing pulses, at least one detection electrode for detecting atrial and ventricular events, at least one stimulation electrode, a memory storing executable instructions, and a processor configured to execute the instructions. The processor is configured to execute the instructions to apply an atrioventricular delay (AVD) between a sensed or stimulated atrial event and the delivery of a ventricular pacing pulse, quantify a degree of fusion between the delivery of a pacing pulse to a cavity and a spontaneous contraction of another cavity, calculate a fusion rate, and modify the value of the AVD applied to the delivery of said ventricular pacing pulse, as a function of a comparison.

Systems and methods for controlling blood pressure by controlling atrial pressure and atrial stretch are disclosed. In some embodiments, a stimulation circuit may be configured to deliver a stimulation pulse to at least one cardiac chamber of a heart of a patient, and at least one controller may be configured to execute delivery of one or more stimulation patterns of stimulation pulses to the at least one cardiac chamber, wherein at least one of the stimulation pulses stimulates the heart such that an atrial pressure resulting from atrial contraction of an atrium overlaps in time a passive pressure build-up of the atrium, such that an atrial pressure of the atrium resulting from the stimulation is a combination of the atrial pressure resulting from atrial contraction and the passive pressure build-up and is higher than an atrial pressure of the atrium would be without the stimulation, and such that the blood pressure of the patient is reduced.

Baseline BiV pacing is delivered and a corresponding baseline BiV efficacy score is determined. Intrinsic AV conduction is allowed and an intrinsic AV conduction interval is determined. BiV fusion pacing is delivered and a corresponding efficacy score is determined, for each of a plurality of different paced AV delays, each determined based on the intrinsic AV conduction interval and a different negative hysteresis delta. The baseline BiV pacing is selected for delivery during a period of time if the baseline BiV efficacy score is better than all of the efficacy scores. BiV fusion pacing is selected for delivery during the period of time, using one of the plurality of different paced AV delays for which a corresponding efficacy score was determined, if the efficacy score corresponding to at least one of the plurality of different paced AV delays is better than the baseline BiV efficacy score.

A method for identifying reversible cardiac dyssynchrony (RCD) of a patient and treating the RCD measures an event relating to a rapid increase in the rate of pressure increase within the left ventricle. The method calculates a first time delay between the event and a first reference time. If the first time delay is longer than a set fraction of electrical activation of the heart, then the presence of cardiac dyssynchrony in the patient is identified. Pacing is applied to the heart, and a second time delay between the event following pacing and a second reference time following pacing is calculated. If the second time delay is shorter than the first time delay, the method identifies a shortening of a delay to onset of myocardial synergy, OoS, thereby identifying the presence of RCD in the patient. Treatment of the RCD is performed.

Systems and methods involve an intrathoracic cardiac stimulation device operable to provide autonomous cardiac sensing and energy delivery. The cardiac stimulation device includes a housing configured for intrathoracic placement relative to a patient's heart. A fixation arrangement of the housing is configured to affix the housing at an implant location within cardiac tissue or cardiac vasculature. An electrode arrangement supported by the housing is configured to sense cardiac activity and deliver stimulation energy to the cardiac tissue or cardiac vasculature. Energy delivery circuitry in the housing is coupled to the electrode arrangement. Detection circuitry is provided in the housing and coupled to the electrode arrangement. Communications circuitry may optionally be supported by the housing. A controller in the housing coordinates delivery of energy to the cardiac tissue or cardiac vasculature in accordance with an energy delivery protocol appropriate for the implant location.

A biventricular (BiV) implantable cardiac stimulator contains a stimulation control unit, one or more stimulation units, an impedance measurement unit and an impedance evaluation unit. The stimulation control unit is operatively connected to one or more stimulation units to control delivery of stimulation pulses by the one or more stimulation units. The stimulation control unit is configured to assess ventricular contractility based on an impedance signal generated by the impedance evaluation unit and to switch between at least a univentricular left ventricular stimulation mode and a biventricular stimulation mode and to evaluate the ventricular contractility in relation to the respective ventricular stimulation mode.

An implantable system detecting electrical signals of a human or animal heart includes a processor, a memory unit, a first detection unit for atrial activity, a second detection unit for right ventricular activity and a third detection unit for left ventricular activity. The system automatically performs steps at regular intervals including detecting an intrinsic right atrial activity using the first detection unit; detecting an intrinsic right ventricular activity using the second detection unit; determining a time between the intrinsic right atrial activity and the intrinsic right ventricular activity, and storing this time as atrioventricular conduction time. Additionally or alternatively the steps include detecting an intrinsic right ventricular activity using the second detection unit; detecting an intrinsic left ventricular activity using the third detection unit; and determining a time between the intrinsic right ventricular activity and the intrinsic left ventricular activity, and storing this time as interventricular conduction time.

A method includes determining whether electrical activity is indicative of atrial fibrillation, determining whether mechanical activity is indicative of atrial fibrillation, and adjusting a pacing parameter or mode based on whether the electrical activity and the mechanical activity are indicative of atrial fibrillation. The electrical activity may be detected based on a far-field measurement. The method may be performed using a leadless implantable medical device.

Systems and methods for controlling blood pressure by controlling atrial pressure and atrial stretch are disclosed. In some embodiments, a stimulation circuit may be configured to deliver a stimulation pulse to at least one cardiac chamber of a heart of a patient, and at least one controller may be configured to execute delivery of one or more stimulation patterns of stimulation pulses to the at least one cardiac chamber, wherein at least one of the stimulation pulses stimulates the heart such that an atrial pressure resulting from atrial contraction of an atrium overlaps in time a passive pressure build-up of the atrium, such that an atrial pressure of the atrium resulting from the stimulation is a combination of the atrial pressure resulting from atrial contraction and the passive pressure build-up and is higher than an atrial pressure of the atrium would be without the stimulation, and such that the blood pressure of the patient is reduced.

A pacemaker having a motion sensor is configured to select an atrial event sensing vector of a multi-axis motion sensor for sensing atrial systolic events from a motion signal produced by the motion sensor. In some examples, the pacemaker determines a maximum amplitude during a sensing window for each one of multiple vector signals produced by the multi-axis motion sensor. The pacemaker may select the atrial event sensing vector signal from among the vector signals based on the determined maximum amplitudes.